Intermittent preventive treatment of malaria provides substantial protection against malaria in children already protected by an insecticide-treated bednet in Mali: a randomised, double-blind, placebo-controlled trial.

Abstract

Previous studies have shown that in areas of seasonal malaria transmission, intermittent preventive treatment of malaria in children (IPTc), targeting the transmission season, reduces the incidence of clinical malaria. However, these studies were conducted in communities with low coverage with insecticide-treated nets (ITNs). Whether IPTc provides additional protection to children sleeping under an ITN has not been established.
To assess whether IPTc provides additional protection to children sleeping under an ITN, we conducted a randomised, double-blind, placebo-controlled trial of IPTc with sulphadoxine pyrimethamine (SP) plus amodiaquine (AQ) in three localities in Kati, Mali. After screening, eligible children aged 3-59 mo were given a long-lasting insecticide-treated net (LLIN) and randomised to receive three rounds of active drugs or placebos. Treatments were administered under observation at monthly intervals during the high malaria transmission season in August, September, and October 2008. Adverse events were monitored immediately after the administration of each course of IPTc and throughout the follow-up period. The primary endpoint was clinical episodes of malaria recorded through passive surveillance by study clinicians available at all times during the follow-up. Cross-sectional surveys were conducted in 150 randomly selected children weekly and in all children at the end of the malaria transmission season to assess usage of ITNs and the impact of IPTc on the prevalence of malaria, anaemia, and malnutrition. Cox regression was used to compare incidence rates between intervention and control arms. The effects of IPTc on the prevalence of malaria infection and anaemia were estimated using logistic regression. 3,065 children were screened and 3,017 (1,508 in the control and 1,509 in the intervention arm) were enrolled in the study. 1,485 children (98.5%) in the control arm and 1,481 (98.1%) in the intervention arm completed follow-up. During the intervention period, the proportion of children reported to have slept under an ITN was 99.7% in the control and 99.3% in intervention arm (p = 0.45). A total of 672 episodes of clinical malaria defined as fever or a history of fever and the presence of at least 5,000 asexual forms of Plasmodium falciparum per microlitre (incidence rate of 1.90; 95% confidence interval [CI] 1.76-2.05 episodes per person year) were observed in the control arm versus 126 (incidence rate of 0.34; 95% CI 0.29-0.41 episodes per person year) in the intervention arm, indicating a protective effect (PE) of 82% (95% CI 78%-85%) (p<0.001) on the primary endpoint. There were 15 episodes of severe malaria in children in the control arm compared to two in children in the intervention group giving a PE of 87% (95% CI 42%-99%) (p = 0.001). IPTc reduced the prevalence of malaria infection by 85% (95% CI 73%-92%) (p<0.001) during the intervention period and by 46% (95% CI 31%-68%) (p<0.001) at the end of the intervention period. The prevalence of moderate anaemia (haemoglobin [Hb] <8 g/dl) was reduced by 47% (95% CI 15%-67%) (p<0.007) at the end of intervention period. The frequencies of adverse events were similar between the two arms. There was no drug-related serious adverse event.
IPTc given during the malaria transmission season provided substantial protection against clinical episodes of malaria, malaria infection, and anaemia in children using an LLIN. SP+AQ was safe and well tolerated. These findings indicate that IPTc could make a valuable contribution to malaria control in areas of seasonal malaria transmission alongside other interventions.
ClinicalTrials.gov NCT00738946. Please see later in the article for the Editors' Summary.

Full text

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Intermittent Preventive Treatment of Malaria Provides
Substantial Protection against Malaria in Children
Already Protected by an Insecticide-Treated Bednet in
Mali: A Randomised, Double-Blind, Placebo-Controlled
Trial
Alassane Dicko1*, Abdoulbaki I. Diallo1, Intimbeye Tembine1, Yahia Dicko1, Niawanlou Dara1, Youssoufa
Sidibe1, Gaoussou Santara1, Halimatou Diawara1, Toumani Conare ´2, Abdoulaye Djimde1, Daniel
Chandramohan3, Simon Cousens3, Paul J. Milligan3, Diadier A. Diallo3, Ogobara K. Doumbo1, Brian
Greenwood3
1Malaria Research and Training Centre, Faculty of Medicine Pharmacy and Dentistry, University of Bamako, Bamako, Mali, 2Centre de Sante ´ de Re ´fe ´rence de Kati, Kati,
Mali, 3London School of Hygiene & Tropical Medicine, London, United Kingdom
Abstract
Background: Previous studies have shown that in areas of seasonal malaria transmission, intermittent preventive treatment
of malaria in children (IPTc), targeting the transmission season, reduces the incidence of clinical malaria. However, these
studies were conducted in communities with low coverage with insecticide-treated nets (ITNs). Whether IPTc provides
additional protection to children sleeping under an ITN has not been established.
Methods and Findings: To assess whether IPTc provides additional protection to children sleeping under an ITN, we
conducted a randomised, double-blind, placebo-controlled trial of IPTc with sulphadoxine pyrimethamine (SP) plus
amodiaquine (AQ) in three localities in Kati, Mali. After screening, eligible children aged 3–59 mo were given a long-lasting
insecticide-treated net (LLIN) and randomised to receive three rounds of active drugs or placebos. Treatments were
administered under observation at monthly intervals during the high malaria transmission season in August, September,
and October 2008. Adverse events were monitored immediately after the administration of each course of IPTc and
throughout the follow-up period. The primary endpoint was clinical episodes of malaria recorded through passive
surveillance by study clinicians available at all times during the follow-up. Cross-sectional surveys were conducted in 150
randomly selected children weekly and in all children at the end of the malaria transmission season to assess usage of ITNs
and the impact of IPTc on the prevalence of malaria, anaemia, and malnutrition. Cox regression was used to compare
incidence rates between intervention and control arms. The effects of IPTc on the prevalence of malaria infection and
anaemia were estimated using logistic regression. 3,065 children were screened and 3,017 (1,508 in the control and 1,509 in
the intervention arm) were enrolled in the study. 1,485 children (98.5%) in the control arm and 1,481 (98.1%) in the
intervention arm completed follow-up. During the intervention period, the proportion of children reported to have slept
under an ITN was 99.7% in the control and 99.3% in intervention arm (p=0.45). A total of 672 episodes of clinical malaria
defined as fever or a history of fever and the presence of at least 5,000 asexual forms of Plasmodium falciparum per
microlitre (incidence rate of 1.90; 95% confidence interval [CI] 1.76–2.05 episodes per person year) were observed in the
control arm versus 126 (incidence rate of 0.34; 95% CI 0.29–0.41 episodes per person year) in the intervention arm,
indicating a protective effect (PE) of 82% (95% CI 78%–85%) (p,0.001) on the primary endpoint. There were 15 episodes of
severe malaria in children in the control arm compared to two in children in the intervention group giving a PE of 87% (95%
CI 42%–99%) (p=0.001). IPTc reduced the prevalence of malaria infection by 85% (95% CI 73%–92%) (p,0.001) during the
intervention period and by 46% (95% CI 31%–68%) (p,0.001) at the end of the intervention period. The prevalence of
moderate anaemia (haemoglobin [Hb] ,8 g/dl) was reduced by 47% (95% CI 15%–67%) (p,0.007) at the end of
intervention period. The frequencies of adverse events were similar between the two arms. There was no drug-related
serious adverse event.
Conclusions: IPTc given during the malaria transmission season provided substantial protection against clinical episodes of
malaria, malaria infection, and anaemia in children using an LLIN. SP+AQ was safe and well tolerated. These findings indicate
that IPTc could make a valuable contribution to malaria control in areas of seasonal malaria transmission alongside other
interventions.
Trial Registration: ClinicalTrials.gov NCT00738946
Please see later in the article for the Editors’ Summary.
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Citation: Dicko A, Diallo AI, Tembine I, Dicko Y, Dara N, et al. (2011) Intermittent Preventive Treatment of Malaria Provides Substantial Protection against Malaria
in Children Already Protected by an Insecticide-Treated Bednet in Mali: A Randomised, Double-Blind, Placebo-Controlled Trial. PLoS Med 8(2): e1000407.
doi:10.1371/journal.pmed.1000407
Academic Editor: Stephen John Rogerson, University of Melbourne, Australia
Received June 22, 2010; Accepted December 16, 2010; Published February 1, 2011
Copyright: ? 2011 Dicko et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by a grant to the London School of Hygiene & Tropical Medicine from the Bill & Melinda Gates Foundation (grant number
41783). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Abbreviations: AQ, amodiaquine; AS, artesunate; CI, confidence interval; EIR, entomological inoculation rate; Hb, haemoglobin; IPT, intermittent preventive
treatment; IPTc, intermittent preventive treatment of malaria in children; IPTi, intermittent preventive treatment of malaria in infants; ITN, insecticide-treated net;
LLIN, long-lasting insecticide-treated net; PE, protective effect; RDT, rapid diagnostic test; SP, sulphadoxine pyrimethamine
* E-mail: adicko@icermali.org
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Introduction
An estimated 863 million people live in sub-Saharan Africa of
whom 16.2% are under 5 y of age [1]. About 300 million people
live in areas where malaria transmission is highly seasonal. Malaria
remains a major cause of morbidity and mortality and is estimated
to cause 881,000 deaths globally per year and sub-Saharan Africa
is disproportionately affected, suffering 91% of global malaria
deaths with 88% occurring in children under 5 y of age [2]. Thus,
in the absence of a vaccine, simple and effective control strategies
are urgently needed to reduce the malaria burden in sub-Saharan
Africa. Vector control, using insecticide-treated bednets (ITNs),
insecticide-treated curtains, or indoor residual spraying (IRS), can
reduce mortality and morbidity from malaria substantially [3], but
in high transmission settings, these interventions provide only
partial protection and additional control measures are needed.
Intermittent preventive treatment (IPT) is a new approach in
the prevention of malaria in infants and older children. Several
randomised controlled trials have demonstrated that IPT of
malaria in infants (IPTi) with sulphadoxine pyrimethamine (SP)
given during routine vaccinations at approximately 2, 3, and 9 mo
of age, reduces the incidence of clinical malaria by 22% to 59%
[4], and this strategy has been shown to be safe and cost effective.
However, in many regions of Africa, the main burden of malaria
falls not on infants but on older children [5]. In parts of Africa,
such as much of the Sahel and sub-Sahel, where malaria
transmission is very seasonal, the incidence of severe malaria
currently peaks at 2 to 3 y of age. As the overall incidence of
malaria decreases in Africa in response to enhanced control efforts,
an effect already being seen in some countries, it can be
anticipated that the mean age of cases of malaria will increase
further. For these reasons, trials have been undertaken in areas of
seasonal malaria transmission to determine whether IPT in
children (IPTc) could be used as an effective malaria control tool
in older children. In Mali, a 69% reduction in the incidence of
clinical malaria was seen in children 0–5 y old when two doses of
SP were given 8 wk apart during the malaria transmission season
[6]. In Senegal, SP plus a single dose of artesunate (AS),
administered on three occasions at monthly intervals during the
peak malaria season, reduced the incidence of clinical malaria by
86% [7]. A subsequent trial of different drug regimens showed that
IPT with SP and amodiaquine (AQ) was even more effective than
SP+AS, providing approximately 95% protection [8]. A further
study, conducted in an area of Ghana with more prolonged
transmission, found that AS+AQ monthly was more effective than
AS+AQ or SP alone given every 2 mo, suggesting that for drugs
such as SP and AQ, monthly administration is needed to achieve
effective IPTc [9]. Bednet coverage among young children was
low at each of the sites where these trials were conducted and use
of ITNs was very uncommon. Use of ITNs is now a favoured
approach to the control of malaria in most parts of Africa and
major efforts are being made to scale up their use. With
international support, ITN coverage is increasing in many malaria
endemic countries in sub-Saharan Africa [10] and it is expected
that almost universal coverage with ITNs in high risk groups, as
called for in the Global Malaria Action Plan [11], will be achieved
in many malaria endemic countries. Thus, following on the initial
encouraging results obtained with IPTc, an issue that needs to be
addressed urgently is whether IPTc can provide significant added
benefit to the protection against malaria provided by ITNs to
warrant its use as a malaria control tool in areas with seasonal
transmission of malaria and a high use of ITNs. It was initially
planned to address this question simultaneously in each of the
three countries Mali, Burkina Faso, and Ghana, using a similar
design and methods. However, the site in Ghana had to be
abandoned because of delays in obtaining regulatory approval for
the use of SP+AQ, the drug combination chosen for the study on
the basis of the results of previous trials and knowledge of the
sensitivity of Plasmodium falciparum to these drugs in the proposed
study areas. Very similar protocols were used for the studies
conducted in Burkina Faso and Mali.
Methods
The protocol of the trial (Text S1), protocol amendment (Text
S5), and CONSORT checklist (Text S2) are available as
supporting information.
Objectives
The primary objective of the study was to determine the degree
to which IPTc given during the malaria transmission season
reduces the incidence of clinical malaria in children who sleep
under a long-lasting insecticide-treated net (LLIN). Secondary
objectives were determination of the impact of this strategy on
severe malaria, all cause hospital admissions, anaemia, nutrition
(wasting, stunting, and being underweight), malaria infection, and
molecular markers of resistance to SP and AQ.
Study Sites
The study was conducted in two rural villages, Djoliba and Siby,
and the small town of Ouelessebougou situated in the district of
Kati in the savannah region of Mali. Djoliba and Siby are located
40 and 30 km south west of the capital city Bamako, respectively,
and Ouelessebougou is located 80 km south of Bamako. In Djoliba
and Siby, community health centres are staffed with a physician
and nurses. In Ouelessebougou, the community health centre is
staffed by an assistant physician and nurses, but located less than
100 m from a district health centre staffed by four physicians and
six nurses. A research team composed of physicians and medical
residents was established in each of the three sites to follow up and
provide health care to the study participants.
Malaria transmission in the study area is highly seasonal and
80%–90% of malaria cases occur between August and November.
The entomological inoculation rate (EIR) was 9.4 and 6.6 infective
bites per person per season, respectively, in Siby and in
Ouelessebougou, two localities far from any river and 37.3
infective bites per person per season in Djoliba located on the bank
of the Niger River (Text S3). The coverage of ITNs at baseline was
33.4% (312/935) in Siby, 84.7% (563/665) in Djoliba, and 89.8%
(2,207/2,458) in Ouelessebougou.
Study Design and Participants
The study was designed as an individually randomised, placebo-
controlled trial of IPTc with SP+AQ in children who received a
LLIN. Children aged 3–59 mo were enumerated and given a
census identification number including a house number to
facilitate their identification at screening, enrolment, and follow-
up. Recruitment was started in Djoliba followed by Siby. In these
communities all available children in the target age group who
were not selected for the baseline survey of drug resistance were
screened and enrolled if they met the inclusion criteria. In the
larger community of Ouelessebougou, children were screened for
enrolment on a first-come first-served basis until the required
sample size was met. Children were eligible to join the study if they
were aged 3–59 mo at the time of enrolment and permanent
residents of the study area with no intention of leaving during the
study period. Exclusion criteria were the presence of a severe,
chronic illness, such as severe malnutrition or AIDS, and a history
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of a significant adverse reaction to SP or AQ. Cases of an acute
illness, such as malaria, were not excluded. Such cases were
treated appropriately and the child randomised and retained in the
trial.
Ethics
The study protocol was reviewed and approved by the Ethical
Committee of the Faculty of Medicine, Pharmacy and Dentistry,
University of Bamako, Mali and by the Ethics Committee of the
London School of Hygiene and Tropical Medicine. Community
consent was obtained at meetings with leaders, heads of families,
and other community members of each locality prior to the start of
the study. Individual, written, informed consent was obtained from
a parent or guardian of each child prior to screening and
enrolment. A Data and Safety Monitoring Board (DSMB) was
established and monitored the trial with the support of a local
medical safety monitor. Current good clinical practices (cGCP)
monitoring of the trial was performed by PharmaClin (http://
www.pharmaclin.com).
Interventions
Every child who was screened was provided with a LLIN
(Permanet, Vestergaard Frandsen) that was marked with the
child’s identification number regardless of whether or not the child
was enrolled. Instructions were given to the parent or guardian on
how to use the net and the importance of using the net regularly
was emphasized. Monitoring of utilisation of ITNs by study
participants was made in 150 randomly selected children each
week and in all study children during the cross-sectional survey
conducted at the end of the malaria transmission season.
Eligible children were treated with a course of SP+AQ or
matching placebos on three occasions at monthly intervals during
the malaria transmission season, starting in August 2008. SP and
AQ were manufactured by Kinapharma Limited and quality
control checks on the drugs for solubility and content were
performed at the London School of Tropical Medicine and
Hygiene, prior to their use in the trial. Tablets met internal
standards for drug solubility and content. Doses of SP and AQ were
based on weight with children stratified into one of the three weight
categories (5–9 kg, 10–18 kg, and $19 kg). SP was given at a dose
of 175/8.75 mg to children 5–9 kg, 350/17.5 mg to children 10–
18 kg, and 550/26.25 mg to those who weighed $19 kg. The
corresponding doses for AQ were 70 mg, 140 mg, and 220 mg,
respectively. AQ was given over 3 d. Drugs were prepackaged to
facilitate administration and putin envelopes with colour codes, one
for each weight group. Within each weight stratum, children were
individually randomised using a computer-generated random
number sequence and blocks of varying length. Treatment
allocations were provided within sealed, opaque envelopes.
Drugs were given under direct observation at a research clinic
by study staff. Children were observed for 30 min after drug
administration. If vomiting occurred during this 30-min period,
drugs were readministered. If vomiting occurred on a second
occasion, this was noted but the drugs were not given again. Such
children were not excluded from the trial and they were eligible to
receive drugs on the subsequent 2 d and during subsequent
monthly IPT rounds. If a child missed the day set for treatment, a
home visit was made to enquire why the child had not been
brought for treatment and the reason was recorded. If the family
wished to continue with treatment but was unable to attend on the
specified day, then treatment was reoffered within an interval of
7 d of the designated date. Children with an acute malaria episode
were treated with artemether-lumefantrine (AL) and did not
receive IPT with SP+AQ if the treatment for acute malaria was
received within 7 d of the scheduled date of IPT. Such children
were eligible for treatment in future treatment rounds
Outcomes
The primary endpoint of the study was the incidence of clinical
malaria; this was defined as the presence of fever (axillary
temperature $37.5uC) or a history of fever in the past 24 h and
the presence of P. falciparum asexual parasitaemia at a density
greater or equal to 5,000 parasites per microlitre. Secondary
endpoints were: (i) the incidence of clinical malaria defined as the
presence of fever or a history of fever in the past 24 h and the
presence of P. falciparum asexual parasitaemia at any density; (ii)
incidence of severe malaria defined according to the WHO criteria
[12]; (iii) malaria infection defined as the presence of asexual
parasitaemia; (iv) mild, moderate, or severe anaemia defined as an
haemoglobin (Hb) concentration ,11 g/dl, ,8 g/dl, and ,5 g/
dl, respectively; (v) hospital admission defined as a stay of at least
24 h in hospital for treatment; (vi) anthropometric indicators
including wasting, stunting, and being underweight as defined by
WHO [13]; and (vii) safety and tolerability measured by the
occurrence of nonserious and serious adverse events.
Passive surveillance for clinical malaria started at the time of the
administration of the first dose of IPTc in August 2008 and
continued until the end of the malaria transmission season in
November/December 2008, 6–7 wk after the last round of IPTc.
Parents were encouraged to bring their child to a study health
centre, where medical staff were available 24 h a day and 7 d a
week,ifthechildbecameunwell.Afingerprickbloodsamplewasbe
obtained from all study children with fever (an axillary temperature
of37.5uCorhigher)ora historyoffeverwithintheprevious24 h for
preparation of a blood film, measurement of Hb concentration, and
for a rapid diagnostic test (RDT) OPTIMAL_IT (Diamed AG) for
malaria. Children who had a positive RDT for malaria were treated
immediately with AL. Severe cases were admitted to the health
centre or referred to the paediatric ward of the Gabriel Toure ´
Hospital in Bamako. Causes of death were assessed within a month
of death using a modified version of the INDEPTH post mortem
questionnaire (http://www.indepth-network.org/index.php?option
=com_ content&task=view&id=96&Itemid=184).
Use of a LLIN was assessed by asking if a child had slept under
an LLIN the previous night and the presence of the net was
checked by field staff. During these home visits, the axillary
temperature of each child was taken and a blood film obtained
regardless of whether or not the child had fever. A RDT was
performed if a child had measured fever or a history of fever
within the previous 24 h and if this was positive, treatment with
AL was given according to national guidelines. At the end of the
malaria transmission season, a cross-sectional survey was under-
taken at which every child was examined, their height and weight
recorded, and a finger prick blood sample obtained for
determination of Hb concentration, preparation of blood films,
and collection of a filter paper sample for subsequent molecular
studies. Safety and tolerability of SP and AQ were monitored
passively during the study period in all the children and actively in
a subset at the time of the administration of IPT (days 0, 1, and 2)
and 1 d after the last dose of treatment (day 3) at each round.
Assessment of Molecular Markers of Drug Resistance
Monitoringof thefrequency of molecular markers ofresistanceto
sulphadoxine, pyrimethamine, and AQ was performed in two cross-
sectional surveys, the first at baseline in August 2008 and the second
during the survey undertaken at the end of malaria transmission
season. The baseline survey was conducted in 256 children
randomly selected from the screening list. These children were
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not enrolled in the placebo control trial. Participants enrolled in the
placebocontroltrialweresurveyedabout6 wkafterthe thirdcourse
of IPTc, at the end of malaria transmission season, to assess whether
administration of IPT with SP+AQ had lead to an increase in
molecularmarkersofresistancetothesedrugs.Thickand thinblood
smears and blood blotted onto filter papers were collected during
both surveys for molecular analysis as described below.
Laboratory Methods
Thick blood films were air dried, stained with Giemsa, and
examined for malaria parasites by two well-trained technicians.
100 high power fields were counted before a film was declared
negative. Parasite density was determined by counting the number
of parasites present per white blood cell (WBC) on a thick smear
and assuming a WBC count of 8,000 per ml. In the case of a
discrepancy (positive/negative or a difference in parasite density
greater than 30%), a third reading was done. The median parasite
density of two or three readings was used. An external quality
control of slide reading performed by the Malaria Diagnosis
Centre of Excellence (MDCoE) of the Walter Reed/Kenya
Medical Research Institute, in Kisumu, Kenya, showed an overall
concordance of more than 90% on parasite detection and 100%
on species identification (Text S4). Hb concentrations were
measured using a haemoglobin analyzer (Hemocue HB 301) on
blood obtained by finger prick.
Filter paper samples from children with a mono-infection of P.
falciparum on blood smears were analysed by nested PCR for
mutations at codons 51, 59, and 108 of the dhfr gene, 437 and 540
of the dhps gene, 76 of mutations in the P. falciparum chloroquine
transporter gene (pfcrt), and 86 of the P. falciparum multidrug
resistance gene one (pfmdr1) according to published methods [14–
16]. Cases of mixed infection (wild type and mutant) were
categorized as mutant.
Sample Size
Calculation of sample size was based on the assumptions that
the clinical attack rate measured by passive surveillance would be
1.0–2.0 attacks per child per year in unprotected children aged 3–
59 mo living in the study areas and that sleeping under an LLIN
would reduce this attack rate by half to 0.5 to 1.0 clinical episode
per child per year. Assuming that children experienced an average
of 0.5 clinical episodes per child per year of sufficient severity to
present to a health facility, to detect a 20% reduction in this
incidence (i.e., from 0.5 to 0.4 attacks per child per year) in
children who receive IPTc, the smallest reduction that would be
likely to make IPTc a worthwhile investment, and allowing for a
20% loss to follow-up, we estimated that approximately 2,000
children (1,000 in each arm) were required for a study with 90%
power at the two-sided 5% level of significance [17]. After the site
in Ghana was dropped, the sample size was increased to 1,500
participants per arm, after an amendment was made to the
protocol (Text S5), which would have 80% power to detect a two-
thirds reduction in the incidence of severe malaria, assuming an
incidence of 2% in children in the control arm. The study was not
powered to detect a smaller reduction in the incidence of severe
malaria but the analysis plan included provision for combination
of the results of this trial with those of a parallel study conducted in
Burkina Faso to provide sufficient size to allow detection of a
smaller impact of IPTc on this end point.
Data Management and Analysis
Data were collected on standardized forms, double-entered, and
verified using MS Access and then exported to Stata (StataCorp)
for additional cleaning and analysis. A data analysis plan was
written and submitted to the DSMB prior to analysis. The final,
cleaned database was locked and a copy sent to the DSMB. An
intention-to-treat analysis was performed. Incidence rates of
clinical malaria, severe malaria, and hospital admissions were
calculated by dividing the number of episodes by the total child
days at risk. Children were not considered at risk for 21 d after
each type of a malaria episode and these days were not included in
the calculation of the child days at risk. The incidence rates in the
two treatment groups were compared using Cox regression to
estimate the incidence rate ratio, with adjustment for age, gender,
and locality, and using a robust standard error to allow for the lack
of independence among repeated episodes in the same child. The
protective effect (PE) of IPTc was computed as 1 minus the
incidence rate ratio. Time to first episode of clinical malaria in the
two arms was examined using Kaplan-Meier plots and compared
using log rank test. Anthropometric data at enrollment and at the
end of season cross-sectional survey were converted into weight-
for-age, height-for-age, and weight-for-height z-scores using
WHO’s anthropometric software (www.who.int/childgrowth/
software/en). Underweight, stunting, and wasting were defined
as z-scores of ,22 for the relevant indicator [13]. Changes in
weight and height between the two groups were compared using
Student’s t test. Frequencies of single mutations as well as the triple
mutant (dhfr 51+59+108) and quadruple mutant (triple mutant +
dhps 437) genotypes were determined and compared between
treatment arms and between the beginning and end of the study.
Proportions of children with binary outcomes were compared
between the two groups using Pearson’s Chi square test or
generalized linear models adjusted for age, gender, and locality.
Results
Trial Profile and Baseline Data
The trial profile is summarised in Figure 1. A total of 3,065
children were screened of whom 3,017 (1,509 in the IPTc arm and
1,508 in the placebo arm) (98%) were enrolled. Reasons for
exclusion are shown in Figure 1. The proportion of children who
completed the follow-up to day 42 after the last round of IPTc was
similar in the control and in the intervention arms (98.5% and
98.1%, respectively). The reasons for withdrawal were withdrawal
of consent (n=29), migration to another location (n=15), a history
of allergy to study drugs (n=4 with two cases confirmed), and
death (n=3). There were no significant differences between
intervention and control groups with regard to their age and
gender distribution, nor in the prevalence of fever, wasting, or
stunting at the time of enrolment (Table 1).
LLIN Usage
Usage of LLINs was assessed for 590 children in the control
group and for 591 children in the intervention group during
weekly home visits, undertaken without prior warning, during the
course of the intervention period. Usage of an LLIN was high in
each of the three study localities and similar between the two
groups (99.7% in the control group versus 99.3% in the
intervention arm; p=0.45).
The Impact of IPTc on Malaria
Among children with fever or history of fever who had an RDT
positive result, 8.8% (112/1,277) turned out to have negative
parasitaemia after microscopical diagnosis of malaria. The impact
of IPTc on episodes of malaria detected through passive
surveillance is presented in Table 2. The incidence of episodes
of uncomplicated malaria (fever or a history of fever in the last
24 h and asexual parasitaemia $5,000/ml) was much lower
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among children in the IPTc arm than among those in the control
arm (0.34 episodes per child/year versus 1.9 episodes per child/
year). The PE against malaria adjusted for age, gender, and
location was 82% (95% confidence interval [CI] 78%–85%)
(p,0.001). An analysis of time to the first episode of clinical
malaria, defined as above, also indicated a strong protective effect
Figure 1. Trial profile.
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of IPTc (p,0.001) (Figure 2). The incidence of malaria defined as
fever or a history of fever in the last 24 h and positive asexual
parasitaemia of any density was also much lower in children in the
IPTc arm compared to those in the control arm (0.41 episodes per
child/year versus 2.4 episodes per child/year), giving a protective
efficacy of 83% (95% CI 80%–86%) (p,0.001). Only 17 cases of
severe malaria occurred during the follow-up period, 15 in the
control group, and two in the intervention group (Table 2), giving
a protective efficacy of 87% (95% CI 42%–99%) (p=0.001). The
two cases of severe malaria in the intervention arm, one of whom
died, occurred more than 3 wk after the third course of IPT.
Incidence rates and the PE of IPTc against clinical malaria by
locality and age category are presented in Table 3. Although the
incidence of clinical malaria varied substantially between the three
study localities, the PE of IPTc was similar in all three areas
regardless of the definition of clinical malaria used. PE was higher
in the lower age groups (3–11 mo and 12–23 mo) compared to the
older age groups ($24 mo) when the definition of clinical malaria
that incorporated the presence of parasitaemia $5,000/ml or any
parasitaemia was used (test for effect modification p#0.001 and
p=0.003, respectively).
The percentage of children with malaria infection detected at
weekly active surveillance visits was 13.2% (74/563) in the control
group compared to 1.9% (11/575) in the intervention group,
giving a protective efficacy of 85%, (95% CI 73%–92%)
(p,0.001). At the end of the transmission season, 13.2% (188/
1,423) of children in the control group were parasitaemic
compared to 7.2% (101/1,405) in the intervention group, giving
a protective efficacy of 46% (95% CI 31%–68%) (p,0.001).
The Impact of IPTc on Anaemia
At the end of the malaria transmission season, the proportion of
the children with anaemia (Hb ,11 g/dl), was significantly higher
in the control group compared to the intervention group (61.1%
[875/1,433] versus 53.9% [766/1,422]) (PE=12%; 95% CI 3%–
20%) (p,0.001). The relative difference was larger for moderate
anaemia (Hb ,8 g/dl) with a prevalence of 3.5% (50/1,433)
Table 1. Baseline characteristics of enrolled children at the
time of administration of the first dose of IPTc.
CharacteristicsIPTc Placebo
Percent (n/N) Percent (n/N)
Age (mo)
3–11 18.2 (274/1,509)18.5 (278/1,508)
12–23 22.5 (339/1,509)20.5 (309/1,508)
24–35 20.5 (310/1,509) 22.0 (332/1,508)
36–4720.0 (302/1,509) 19.4 (293/1,508)
48–5918.8 (284/1,509)19.6 (296/1,508)
Gender
Male 47.7 (720/1,509)50.1 (755/1,508)
Female 52.3 (789/1,509)49.9 (753/1,508)
Weight (kg)
5–934.8 (525/1,509)34.7 (523/1,508)
10–863.1 (952/1,509)63.2 (953/1,508)
$19 2.1 (32/1,509)2.1 (32/1,508)
Nutritional factors
Underweight16.1 (238/1,480)15.1 (223/1,477)
Wasting11.0 (163/1,480)12.5 (185/1,477)
Stunting22.7 (336/1,480) 23.8 (352/1,477)
Fever 7.2 (105/1,460) 7.6 (111/1,464)
doi:10.1371/journal.pmed.1000407.t001
Figure 2. Time to first episode of clinical malaria defined as fever (temperature $ $37.56C) or history of fever in the last 24 h and
parasitaemia $ $5,000/m ml in the intervention and control arms. Kaplan-Meier survival estimates with pointwise 95% confidence bands.
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versus 1.9% (27/1,422) in the control and intervention groups,
respectively (PE=47%; 95% CI 15%–67%) (p=0.007). No cases
of severe anaemia (Hb ,5 g/dl) were observed in either treatment
group at the time of the postintervention survey. However, during
the follow-up period, a total of eight cases of severe anaemia
occurred, two in the intervention arm and six in the control arm.
The two participants in the intervention group who developed
severe anaemia had not received a complete course of IPT at the
time that they developed their severe anaemia.
The Impact of IPTc on Nutritional Indicators
The impact of IPTc on nutritional indicators is presented in
Table 4. The proportions of children with wasting, stunting, and
being underweight at the end of the malaria transmission season
were similar between the control and intervention arms However,
weight gain during the intervention period was 97 g (95% CI
37 g–157 g) more among children in the intervention arm
compared to that recorded among children in the control arm.
Changes in height were similar between the two arms with an
increase of 2.3 cm (95% CI 2.2 cm–2.5 cm) in children in the
intervention arm compared to an increase of 2.4 cm (95% CI
2.2 cm–2.5 cm) in children in the control arm.
The Impact of IPTc on Molecular Markers of Antimalarial
Drug Resistance
The frequencies of molecular markers associated with resistance
to SP and AQ in the two groups at baseline and postintervention
are presented in Table 5. The frequencies of individual and
multiple dhfr and dhps mutations in the placebo group were similar
in pre- and postintervention periods. The frequencies of all
individual dhfr and dhps and of the triple dhfr (51, 59, 108) and
quadruple dhfr (51, 59, 108) + dhps 437 mutations were higher in
the intervention than in the control group at the end of the
surveillance period and, for the dhfr 59, dhps 437, triple and
quadruple mutations, differences between groups were statistically
significant. Frequencies of the pfcrt 76 and pfmdr1 86 did not
change significantly over time and were similar postintervention in
the intervention and control groups.
The Impact of IPTc on Hospital Admissions and Death
Hospital admissions and deaths that occurred during the study
period are listed in Table 6. 19 hospital admissions of at least 24 h
were recorded; nine of these were recorded in children in the
control arm and ten in children in the intervention arm. The
incidence rates of hospital admissions per child/year were 0.0225
episodes in the control group versus 0.0251 in the intervention
arm (p=0.81). There were five deaths, two in the control arm and
three in the intervention arm. Two of the five deaths were due to
malaria (one in each group). Both occurred during hospitalisation
while the remaining three deaths occurred at home. On the basis
of the results of a verbal autopsy, these deaths were thought to be
due to poisoning by traditional medicines, meningitis and
anaemia, and secondary bleeding following a circumcision,
respectively.
Safety and Tolerability
There was no serious adverse event related to the study drugs.
The frequencies of adverse events following the administration of
IPTc with SP+AQ or placebo, using active surveillance are
summarized in Table 7. The frequencies of adverse events were
similar between the control and intervention arms. However,
there was a tendency toward a higher frequency of vomiting and
of loss of appetite in the intervention arm compared to the
control arm (4.0% versus 1.9%, p=0.06 for vomiting and 1.9%
versus 0.8%, p=0.08 for loss of appetite). Proportions of children
with skin rash and itching on at least at one occasion were similar
between the two arms. Four participants in the intervention arm
were withdrawn from the study because of reactions to study drug
versus none in the control arm. Two of these children had a
documented skin rash at physical examination (one after the first
dose of IPT and the other after the second dose of IPT) and these
were assessed as being related to study drugs. Both were
moderate in intensity, did not involve bullous eruptions, and
resolved within 2 d. The parent of the third participant reported
itching. Physical examination was normal but the child was
withdrawn from the study on precautionary grounds. The fourth
participant had an acute respiratory infection at the time of
Table 2. Impact of IPTc on episodes of clinical malaria in children in Mali.
OutcomesIPTcPlacebo
Unadjusted
IRRs
(95% CI)p-Value
Adjustedc
IRRs
(95% CI)
PE
(95% CI)
p-Value
n
Episodes
Years at
Riska
Incidence Rate
(95% CI)b
n
Episodes
Years at
Risk
Incidence Rate
(95% CI)b
Fever or
history
of fever
and any
asexual
parasitaemia
149362.150.41
(0.35–0.48)
832 345.64 2.40 (2.25–2.58)0.17
(0.14–0.20)
,0.0010.17
(0.14–0.20)
83
(80–86)
,0.001
Fever or
history
of fever and
parasitaemia
$5,000
126369.410.34
(0.29–0.41)
672 354.141.90
(1.76–2.05)
0.18
(0.15–0.22)
,0.001 0.18
(0.15–0.22)
82
(78–85)
,0.001
Severe
malaria
2 399.100.005
(0.0006–0.0181)
15400.870.037
(0.0209–0.0617)
0.13
(0.01–0.58)
0.001—87
(42– 99)
0.001
aChildren were not considered at risk for 21 d after each type of a malaria episode.
bIncidence rate/child/year. Note the incidence relate refers to only the 3-mo surveillance period and is not an annual rate.
cAdjusted for age, gender, and location. 95% CI constructed using a robust standard error.
IRR, incidence rate ratio.
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administration of the first dose of IPT. No adverse event was
recorded at the time of routine surveillance but the parents
requested withdrawal of their child from the study at the time of
the second round of IPTc.
Discussion
This study has shown that three doses of IPTc with SP+Q given
at monthly intervals during the peak transmission season reduced
the incidence of uncomplicated and severe malaria by 80% in
children 3–59 mo of age who slept under an ITN in three localities
in Mali despite the difference in ITN use at baseline. This level of
protective efficacy is similar to that reported in a previous trial
conducted in an area of Senegal with a coverage of ITNs of less
than 1% [7], suggesting that the relative efficacy of IPTc is not
reduced by the use of an ITN at the time of the intervention. Two
studies have shown that in pregnant women, IPT adds little benefit
to the protection afforded by an ITN, at least in multigravidae
[18,19]. This finding is not the case for IPTc in children, as the
strategy remained highly efficacious even when deployed in a
community with a high usage of ITNs.
Despite the large difference in background incidence of malaria
in the three sites, suggesting high variability in transmission
intensity, the protectiveefficacy of IPTc against clinicalmalaria was
high and similar between the three sites. This suggests that similar
efficacies of IPTc against clinical malaria can be expected in areas
with different transmission intensities and baseline ITN coverage.
Surprisingly, Siby and Ouelessebougou, which had a low EIR (less
than ten infective bites per person/season), had a higher malaria
attack rate than Djoliba, which had a higher EIR (37 infective bites
per person/season). High malaria infection and attack rates have
been reported previously in the context of a low EIR (3.5 infective
bitesper person/season)inMali [20],and similarmalariaincidence
rates were found in children aged 0–5 y in two areas despite a more
than 10-fold difference in EIR [21]. However, these apparently
anomalous results could have also been due to imprecision in the
determination of the EIR, which can vary markedly with time and
space or to a difference in the efficiency of transmission. Early
detection and treatment of malaria cases is known to reduce
hospital admission and deaths due to malaria [22,23]. Early
detection and prompt treatment was available in our carefully
controlled study and the protective effect of IPTc on severe malaria
or death might be more marked than we observed if IPTc was
deployed in a community that did not have such ready access to
health care. Parasite prevalence, as assessed by weekly surveys
during the intervention period was reduced by 85% in children
who received IPTc, but this difference dropped to 46% at the end
of the intervention period suggesting that the prophylactic effect
of the last dose of SP+AQ had begun to decline 6 wk after
administration, as has been found in studies of IPTi [24].
Table 3. Effect of area of residence and age on the protective efficacy of IPTc against clinical episodes of malaria.
Outcomes According
to Area of Residence
and Age Category
IPTc Placebo
Unadjusted RR
(95% CI)
p-Value
Adjusted RR
(95% CI)
PE (95%
CI)p-Value
Episodes
(Years
at Risk) Incidence Ratea
Episodes
(Years
at Risk) Incidence Ratea
Clinical malaria defined as fever or history of fever in the last 24 h and asexual parasitaemia $ $5,000/m ml
Locality
Djoliba11 (73.77)0.15 (0.08–0.27) 74 (73.49)1.00 (0.80–1.26) 0.13 (0.10–0.18)
,0.0010.15 (0.08–0.28)85 (72–92) ,0.001
Siby70 (93.32) 0.75 (0.59–0.94)308 (90.57)3.40 (3.04–3.80) 0.13 (0.07–0.24)
,0.0010.22 (0.17–0.29)78 (71–83) ,0.001
Ouelessebougou 45 (202.55)0.22 (0.17–0.30)292 (190.20)1.53 (1.37–1.72) 0.21 (0.16–0.26)
,0.0010.14 (0.10–0.20)86 (80–90) ,0.001
Age (mo)
3–116 (68.64)0.09 (0.04–0.19)52 (66.60) 0.78 (0.59–1.02) 0.11 (0.05–0.26)
,0.0010.13 (0.05–0.29)87 (71–95) ,0.001
12–2312 (83.00)0.14 (0.08–0.25) 134 (72.40)1.85 (1.56–2.19) 0.08 (0.04–0.14)
,0.001 0.07 (0.04–0.13)93 (87–96) ,0.001
24–3538 (76.63)0.50 (0.36–0.68) 173 (77.96)2.22 (1.91–2.58)0.22 (0.15–0.33)
,0.0010.23 (0.15–0.34)77 (66–85) ,0.001
36–47 36 (72.51) 0.50 (0.36–0.69)153 (67.84)2.26 (1.92–2.64)0.22 (0.15–0.31)
,0.0010.21 (0.15–0.31) 79 (69–85) ,0.001
48–59 34 (66.91)0.51 (0.36–0.71) 156 (66.43)2.34 (2.00–2.74)0.21 (0.14–0.32)
,0.0010.22 (0.15–0.32) 78 (68–85) ,0.001
Clinical malaria defined fever or history of fever in the last 24 h and asexual parasitaemia regardless of the density
Locality
Djoliba12 (72.05)0.17 (0.09–0.29) 90 (73.40) 1.22 (1.0–1.50)0.13 (0.10–0.18)
,0.0010.14 (0.10–0.18) 86 (82 –90) ,0.001
Siby 83 (90.86)0.91 (0.74–1.13) 372 (86.41)4.30 (3.88–4.76)0.13 (0.07–0.24)
,0.0010.14 (0.07–0.26) 86 (74 –93) ,0.001
Ouelessebougou54 (199.25)0.27 (0.21–0.35)370 (185.82)1.99 (1.80–2.20)0.21 (0.16–0.26)
,0.0010.21 (0.16–0.26) 79 (74–84) ,0.001
Age (mo)
3–11 10 (68.15)0.15 (0.08–0.27)72 (65.96)1.09 (0.86–1.38)0.13 (0.07–0.26)
,0.0010.14 (0.07–0.27)86 (73–93) ,0.001
12–2315 (81.60)0.18 (0.11–0.30) 153 (71.07)2.15 (1.83–2.52)0.08 (0.05–0.14)
,0.0010.08 (0.05–0.14) 92 (86–95) ,0.001
24–35 47 (75.18)0.62 (0.47–0.83) 206 (76.20)2.70 (2.36–3.10)0.23 (0.17–0.31)
,0.0010.23 (0.16–0.33) 77 (67–84) ,0.001
36–47 39 (70.23)0.55 (0.40–0.76) 200 (65.44)3.06 (2.66–3.51)0.18 (0.13–0.25)
,0.0010.18 (0.13–0.25) 82 (75–87) ,0.001
48–59 38 (65.04)0.58 (0.42–0.80) 194 (63.98)3.03 (2.63–3.49)0.19 (0.13–0.27)
,0.0010.19 (0.13–0.28) 81 (72–87) ,0.001
aIncidence rate expressed as number of episodes/child/year. Note that this is based on the 3-mo surveillance period and does not correspond to an annual rate.
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We observed a 47% reduction in the proportion of children
with moderately severe anaemia (Hb ,8 g/dl) as a result of
administration of IPTc. This impact on anaemia is consistent
with the reduction of 45% in incidence of anaemia observed
when AS+AQ was given at monthly intervals over 6 mo in
Ghana, although in the Ghanaian study there was no difference
in the proportion of children with anaemia at the end of the 6-mo
intervention [9]. We did not detect any difference between the
intervention and control arms in wasting, stunting, or under
weight. This finding is consistent with a previous study in Senegal
[25], which did not find evidence of an impact of IPTc on
wasting, stunting, or being under weight at the end of the
transmission season but only on triceps and subscapular skinfold,
indicators that were not assessed in our study. However, in line
with the Senegalese study, we found an increase in weight gain in
the IPTc arm compared to the control arm during the course of
the intervention period. More marked effects on nutritional
measurements were found during a parallel study conducted
in Burkina Faso [26], perhaps because the force of infection
was higher in the Burkina Faso than in the Mali study areas
and malaria, thus, a more important contributor to impairment
of weight gain in the Burkina Faso than in the Mali study
areas.
SP+AQ was chosen as the drug combination for use in the trial
on the basis of the results of previous studies that had shown this to
be an effective combination for IPTc. This drug combination was
generally well tolerated and no serious adverse event attributable
to the study drugs was reported. The proportions of children with
mild-to-moderate adverse events using active surveillance were not
significantly different between the two arms, although there was a
trend towards a higher frequency of vomiting and loss of appetite
in the intervention group. In the parallel study in Burkina using
the same drugs, a higher frequency of vomiting was found in the
intervention arm [26]. However, even in the placebo group the
frequency of vomiting was higher than in this study, suggesting a
difference in the way in which minor side effects were solicited in
the two study areas. Cisse et al. [7] reported a modest increase in
vomiting in children who took SP+AS compared to those who
took placebo in Senegal, while Kweku et al. [9] found no
difference in incidence of these adverse events between IPTc
intervention and control arms when using SP or AQ. Four
withdrawals in the intervention arm were reported to be due to
reactions to study drugs. In two cases, the presence of a skin rash
was confirmed, another child had itching, and the final withdrawal
followed the occurrence of an acute respiratory tract infection at
the time of administration of the first round of IPTc. It is possible
that this event was considered by the parents as a reaction to the
study drugs. The safety of SP and AQ has been a concern in
relation to their use for IPTc [27–30]. However, there is a growing
body of evidence from studies in the last few years [4,6,7,9,26,30]
that these drugs are safe when used for IPT in pregnant women,
infants, or children, and no safety concerns have arisen following
the use of SP+AQ for IPTc on a large scale in Senegal.
The efficacy of IPTc against clinical malaria has now been
demonstrated in a number of studies, including the current trial
and a parallel one conducted in Burkina Faso [26]. Is the evidence
now strong enough to support the introduction of IPTc into
countries with seasonal malaria transmission? Evidence from
studies of IPT in infants [31,32] suggests that prophylaxis is the key
protective mechanism of IPT and that long-acting drugs are
needed for effective IPTc. Currently, the SP+AQ combination
Table 4. Effect of IPTc on nutritional indicators in children at
the end of the malaria transmission season.
Nutritional
IndicatorsPlacebo IPTc Adjusted Analysis
Percent nPercent nOR (95% CI)a
p-
Value
Wasting5.6 1,3644.31,360 0.75 (0.53–1.07)0.12
Stunting25.2 1,36524.6 1,361 0.96 (0.81–1.15)0.69
Underweight12.81,36510.9 1,361 0.84 (0.66–1.06)0.15
aAdjusted for age, sex, and locality.
doi:10.1371/journal.pmed.1000407.t004
Table 5. Frequencies of molecular markers of resistance to SP and AQ at baseline and at the end of the intervention period in
intervention and control arms.
Molecular MarkersBaselinePostintervention
Baseline Versus Overall
Postintervention p-Value
IPTcPlacebo
n
Percent
Mutant
n
Percent
Mutant
n
Percent
Mutant
p-Value
DHFR 5148 62.5 78 75.6148 66.2 0.144 0.35
DHFR 5948 60.4 7876.914859.5 0.009 0.50
DHFR 108 4178.076 78.9139 71.20.2170.58
DHPS 43747 38.383 67.5165 43.6
,0.0010.09
DHPS 540 450 82 7.31653.6 0.2050.82
Triple DHFR mutations 41 58.57669.7 139 54.0 0.0240.90
Quadruple mutants
(triple DHFR + DHPS
437)
4122.07553.3139 28.1
, 0.0010.07
Pfcrt-76 4680.4 7984.8 15675.00.0850.25
Pfmdr1-864645.6 7636.8 15634.6 0.739.0.19
n= number of participants with parasitaemia at blood smear tested.
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meets this requirement in West Africa where both of these drugs
are still reasonably effective as has been shown to be the case in the
study area (Text S6). Studies conducted in Senegal and in Ghana
[8,30] have compared different drug combination and regimens
and shown that currently SP+AQ at monthly intervals is the
best combination. However, the continuing efficacy of SP cannot
be guaranteed and alternative regimens for IPTc will be required
in the future, which might include the long-acting drug
piperaquine.
Unlike the case of IPT in pregnant women and infants, IPT in
children has no established delivery system, raising concerns as to
whether it could be implemented as a control measure. However,
studies conducted in Ghana and The Gambia have shown that
high coverage with IPTc can be obtained using community health
workers [30,33], and this appears the most promising way of
delivering this intervention.
Another concern over the widespread deployment of IPTc is
that this will enhance the spread of drug resistance. Therefore, we
studied the presence of molecular markers associated with
resistance before and after the intervention in children in the
intervention or control group. The dhfr 59 and dhps 437 mutations
associated with pyrimethamine and sulphadoxine resistance,
respectively, were found significantly more frequently at the end
of the malaria transmission season in parasites obtained from
children in the intervention group than in those obtained from
children in the control group, and this led to higher frequencies of
the triple dhfr mutants and the quadruple mutant (triple dhfr + dhps
437) associated with significant resistance to SP in children who
had received IPTc. This increase in the frequency of these
mutations is consistent with a previous report in Senegal [7]. As in
Senegal, the number of children in the intervention group carrying
a resistant parasite was less than in children in the control group
because of the substantial reduction in the overall prevalence of
Table 7. Proportions of children with adverse events on at
least one occasion during three rounds of IPTc treatment
using the active surveillance.
Adverse Events IPTcPlaceboORs (95% CI)p-Value
Percent (n/N) Percent (n/N)
Fever10.1 (69/686) 9.9 (66/669)1.02 (0.72–1.46)0.91
Vomiting4.0 (19/475)1.9 (9/473)2.1 (0.96–4.80)0.06
Drowsiness 0.1 (1/686) 0 (0/669)——
Itching1.0 (7/686) 0.6 (4/667)1.7 (0.50–5.86) 0.39
Diarrhoea6.7 (46/686)4.6 (31/669) 1.48 (0.92–2.36) 0.10
Skin rash0.3 (2/686) 0.8 (5/668) 0.39 (0.7–2.0)0.26
Coughing 8.2 (56/686)6.0 (40/631)1.40 (0.92–2.13)0.12
Loss of appetite1.9 (13/686) 0.8 (5/668)2.56 (0.90–7.22) 0.08
Jaundice 0 (0/686)0.1 (1/667)——
doi:10.1371/journal.pmed.1000407.t007
Table 6. Hospital admissions and deaths by treatment arms.
NumberingTreatment ArmDate Cause Outcome
Hospital admission
1 Placebo 11/8/2008 Severe malaria Recovered
2 Placebo10/25/2008 Severe anaemiaRecovered
3 Placebo9/27/2008Severe malariaRecovered
4 Placebo11/9/2008 Severe malariaRecovered
5 Placebo12/7/2008Severe malaria Recovered
6 Placebo 9/18/2008 Severe malariaRecovered
7 Placebo9/16/2008Severe malariaDeath
8 Placebo 9/18/2008Severe malariaRecovered
9 Placebo11/16/2008Severe malariaRecovered
10 IPTc11/23/2008Gastro-enteritisRecovered
11 IPTc11/5/2008 Severe malariaDeath
12 IPTc12/2/2008Respiratory infection Recovered
13 IPTc 10/11/2008Gastro-enteritis Recovered
14IPTc 8/13/2008Severe anaemiaRecovered
15IPTc 9/21/2008Asthma Recovered
16IPTc 12/3/2008 Severe malariaRecovered
17 IPTc11/11/2008Respiratory infectionRecovered
18IPTc11/4/2008 Febrile convulsionsRecovered
19IPTc9/19/2008Respiratory infectionRecovered
Deaths out of hospitala
1Placebo11/08/08Intoxication to traditional medicines—
2IPTc 09/11/08Meningitis—
3 IPTc09/17/08 Anaemia secondary to circumcision—
aDoes not include death occurred following hospital admissions listed above.
doi:10.1371/journal.pmed.1000407.t006
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parasitaemia. Although IPTc may have contributed to the increase
in frequency of some of resistant markers in this and other studies,
the true impact on the resistance of SP and AQ remains to be
established. Despite a prevalence of quadruple mutants of about
37%, the SP+AQ combination was highly effective in clearing
parasitaemia from children resident in the study area with
asymptomatic parasitaemia (Text S6).
As is the case with any successful malaria intervention,
administration of IPTc to children during several, successive
malaria transmission seasons could interfere with the development
of naturally acquired immunity, raising concerns that there would
be an increased period of risk (rebound malaria) during the period
immediately after the intervention was stopped if exposure levels
remained high. The risk of malaria for children in this trial in the
year after the intervention was stopped has been studied and the
results are currently being analysed. However, several years of
administration would be needed to define the degree to which
acquisition of natural immunity would be impaired. It is very
unlikely that this would outbalance the substantial gains made
during the period when the drug was given.
Our study has several strengths. First, the double-blind,
randomised controlled design prevented a number of biases in the
selection assignment of the participants to the two arms as well as in
assessing the outcomes. A second strength is that this is the largest
IPTc efficacy trial done so far, providing a more precise estimation
of the outcomes measured. Third, the trial was conducted in three
localities with different malaria incidence rates, allowing the efficacy
of this strategy under different levels of malaria transmission to be
assessed. The design would have been stronger if a factorial design
hadbeenused to assesstheindividualand combined impactofIPTc
andITN,butsuchatrialwouldbeunethicalastheefficacyofITNis
already established [3] and use of ITNs is policy in Mali. Other
potential limitations of the study include the duration of evaluation,
which focused only on about 15 wk of follow-up during the malaria
transmission season. However, it is well established that the in the
Sahel region of Mali, 85%–90% of clinical malaria cases occur
during the period of August to November, and efficacy of this
strategy remained high in a previous, smaller study when efficacy
was computed over 12 mo period [6,34].
In summary, IPTc given during the malaria transmission
season, provided substantial additional protection against clinical
malaria, infection with malaria, and anaemia to that provided by
ITNs. IPTc with SP+AQ was safe and well tolerated. As the
international community moves towards the target of malaria
elimination, new malaria control tools will be needed [11]. IPT in
children targeting the transmission season appears to be one of the
strongest available tools to achieve this goal. Our findings support
the need for an early review of whether IPTc can now be
recommended as a component of malaria control in areas with
seasonal malaria transmission.
Supporting Information
Text S1
and ITNs on morbidity from malaria in African children.
Found at: doi:10.1371/journal.pmed.1000407.s001 (0.19 MB
PDF)
Study protocol: A trial of the combined impact of IPT
Text S2
Found at: doi:10.1371/journal.pmed.1000407.s002 (0.22 MB
DOC)
CONSORT checklist.
Text S3
Found at: doi:10.1371/journal.pmed.1000407.s003 (0.45 MB
PDF)
Entomological investigations.
Text S4
diagnosis.
Found at: doi:10.1371/journal.pmed.1000407.s004 (0.10 MB
PDF)
External quality assurance of malaria microscopic
Text S5
Found at: doi:10.1371/journal.pmed.1000407.s005 (0.11 MB
PDF)
In vivo efficacy of the SP+AQ combination used for
IPTc in the study area.
Found at: doi:10.1371/journal.pmed.1000407.s006 (0.51 MB
PDF)
Protocol amendment.
Text S6
Acknowledgments
We are very grateful to the study participants, the populations, the
members of community health associations, and the staff of the health
centres of Djoliba, Siby, and Ouelessebougou for their cooperation
throughout the study. Special thanks to Amit Bhasin, Manuela Claite, the
Mali Service Center headed by Sean Cantella for proving administrative
and financial services support to the project. Our specials thanks go also to
the members of the Data and Safety Monitoring Board, (Geoffrey Targett
[chair], Jim Todd, Daniel Ansong, Fousseni Dao, and Tatiana Keita and
Helena Gatakaa) to the local Medical Monitor, Aminata Diallo, and to the
Malian Ministry of the Health for their support and advice. We are grateful
to the Malaria Diagnosis Centre of Excellence of Kisumu for the external
quality control of slide reading, Sekou F. Traore ´ and his team for the
determination of the entomological data collection and analysis, and to
Harparkash Kaur for performing analysis for the quality control of the
study drugs and for determination of insecticide concentration on the
samples of bednets. We thank KINAPHARMA Limited who manufac-
tured the trial drugs and the World Swim against Malaria for help in
obtaining and distributing LLINs.
Author Contributions
ICMJE criteria for authorship read and met: A Dicko, AI Diallo, I
Tembine, Y Dicko, N Dara, Y Sidibe, G Santara, H Diawara, T Conare ´,
A Djimde, D Chandramohan, S Cousens, PJ Milligan, DA Diallo, OK
Doumbo, B Greenwood. Agree with the manuscript’s results and
conclusions: A Dicko, AI Diallo, I Tembine, Y Dicko, N Dara, Y Sidibe,
G Santara, H Diawara, T Conare ´, A Djimde, D Chandramohan, S
Cousens, PJ Milligan, DA Diallo, OK Doumbo, B Greenwood. Designed
the experiments/the study: A Dicko, T Conare ´, D Chandramohan, S
Cousens, PJ Milligan, DA Diallo, OK Doumbo, B Greenwood. Analyzed
the data: A Dicko, PJ Milligan, DA Diallo. Collected data/did experiments
for the study: A Dicko, AI Diallo, I Tembine, Y Dicko, N Dara, Y Sidibe,
G Santara, H Diawara, A Djimde. Enrolled patients: A Dicko, I Tembine,
Y Dicko, Y Sidibe, G Santara. Wrote the first draft of the paper: A Dicko.
Contributed to the writing of the paper: A Dicko, AI Diallo, I Tembine, Y
Dicko, N Dara, Y Sidibe, G Santara, H Diawara, T Conare ´, A Djimde, D
Chandramohan, S Cousens, PJ Milligan, DA Diallo, OK Doumbo, B
Greenwood. Oversaw the overall implementation of the trial: DA Diallo.
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Editors’ Summary
Background. Malaria accounts for one in five of all
childhood deaths in Africa and of the one million annual
malarial deaths world-wide, over 75% occur in African
children ,5 years old infected with Plasmodium falciparum.
Malaria also causes severe morbidity in children, such as
anemia,lowbirth-weight,
problems, which compromise the health and development
of millions of children living in malaria endemic areas. As
much of the impact of malaria on African children can be
effectively prevented, significant efforts have been made in
recent years to improve malaria control, such as the
implementation of intermittent preventive treatment (IPT)
of malaria.
IPT involves administration of antimalarial drugs at defined
time intervals to individuals, regardless of whether they are
known to be infected with malaria, to prevent morbidity and
mortality. IPT was initially recommended for pregnant
women and recently this strategy was extended to include
infants (IPTi). Now, there is also intermittent preventive
treatment of malaria in children (IPTc), which is designed to
protect against seasonal malaria transmission including
those above one year of age.
epilepsy, andneurological
Why Was This Study Done? Large clinical trials have
shown that IPTc involving the administration of two to three
doses of an antimalarial drug (sulphadoxine pyrimethamine
[SP] and artesunate [AS] or amodiaquine [AQ]) during the
high malaria transmission season effectively reduces the
incidence of malaria. However, these studies were conducted
in countries where the use of insecticide-treated bednets—
an intervention that provides at least 50% protection against
morbidity from malaria and is the main tool used for malaria
control in most of sub-Saharan Africa—was relatively low.
Therefore, it is unclear whether IPTc will be as effective in
children who sleep under insecticide-treated bednets as has
been previously shown in communities where insecticide-
treated bednet usage is low. So to determine the answer to
this important question, the researchers conducted a
randomized, placebo controlled trial of IPTc with SP+AQ
(chosen because of the effectiveness of this combination in a
pilot study) in children who slept under an insecticide-
treated bednet in an area of seasonal malaria transmission in
Mali.
What Did the Researchers Do and Find? The researchers
enrolled 3,017 eligible children aged 3–59 months into a
randomized double-blind, placebo-controlled trial during the
2008 malaria transmission season in Mali. All children were
given a long-lasting insecticide-treated bednet at the start of
the study with instructions to their family on the correct use
of the net. Children were then randomized into two arms—
1,509 were allocated to the intervention group and 1,508 to
the control group—to receive three courses of IPTc with SP
plus AQ or placebos given at monthly intervals during the
peak malaria transmission season. The researchers monitored
the incidence of malaria throughout the malaria season and
also monitored the use of long-lasting insecticide-treated
bednets throughoutthestudy
researchers conducted a cross-sectional survey in 150
randomly selected children every week and in every child
enrolled in the trial 6 weeks after the last course of IPTc, to
measure their temperature, height and weight, and blood
hemoglobin and parasite level.
The number of children who slept under their long-lasting
insecticide-treated bednet was similar in both arms. During
the intervention period, the researchers observed a total of
672 episodes of clinical malaria (defined as fever or a history
of fever and the presence of at least 5,000 asexual forms of
Plasmodium falciparum per microliter) in the control arm
versus 126 episodes in the intervention arm, which is an
incidence rate of 1.90 episodes per person year in the control
arm versus 0.34 in the interventions arm—giving a
protective efficacy of 87%. IPTc reduced the prevalence of
malaria infection during the intervention period by 85% and
by 46% at the end of the intervention period. The prevalence
of moderate anemia was also reduced (by 47%) at the end of
intervention period. The frequencies of adverse events were
similar between the two arms and there were no drug-
related serious adverse events.
period. Inaddition,
What Do These Findings Mean? The results of this study
show that in peak malarial transmission season in Mali, IPTc
provides substantial additional protection against episodes
of clinical malaria and severe malaria in children sleeping
under long-lasting insecticide-treated bednets. In addition,
intermittent preventive treatment of malaria with SP plus AQ
appears to be safe and well tolerated for use in children.
Additional Information. Please access these websites via
the online version of this summary at http://dx.doi.org/10.
1371/journal.pmed.1000407.
N This topic is further discussed in two PLoS Medicine
research articles by Konate ´ et al. and Bojang et al., and a
PLoS Medicine Perspective by Beeson
N Roll Back Malaria has information about malaria in children,
including intervention strategies and an information sheet
on insecticide-treated bednets
N UNICEF also provides comprehensive information about
malaria in children
N The Intermittent Preventive Treatment in Infants Consor-
tium (ipti) provides information on intermittent preventive
treatment in infants
Efficacy of IPTc and High ITN Use in Mali
PLoS Medicine | www.plosmedicine.org 14February 2011 | Volume 8 | Issue 2 | e1000407