[show abstract][hide abstract] ABSTRACT: Primaquine is the only available drug that clears mature Plasmodium falciparum gametocytes in infected human hosts, thereby preventing transmission of malaria to mosquitoes. However, concerns about dose-dependent haemolysis in people with glucose-6-phosphate dehydrogenase (G6PD) deficiencies have limited its use. We assessed the dose-response association of single-dose primaquine for gametocyte clearance and for safety in P falciparum malaria.
We undertook this randomised, double-blind, placebo-controlled trial with four parallel groups in Jinja district, eastern Uganda. We randomly allocated Ugandan children aged 1-10 years with uncomplicated falciparum malaria and normal G6PD enzyme function to receive artemether-lumefantrine, combined with either placebo or with 0·1 mg/kg, 0·4 mg/kg, or 0·75 mg/kg (WHO reference dose) primaquine base. Randomisation was done with computer-generated four-digit treatment assignment codes allocated to random dose groups in block sizes of 16. Study staff who provided care or assessed outcomes and the participants remained masked to the intervention group after assignment. The primary efficacy endpoint was the non-inferiority of the mean duration of gametocyte carriage in the test doses compared with the reference group of 0·75 mg primaquine per kg, with a non-inferiority margin of 2·5 days. The primary safety endpoint was the superiority of the arithmetic mean maximum decrease in haemoglobin concentration from enrolment to day 28 of follow-up in the primaquine treatment groups compared with placebo, with use of significance testing of pairwise comparisons with a cutoff of p=0·05. The trial is registered with ClinicalTrials.gov, number NCT01365598.
We randomly allocated 468 participants to receive artemether-lumefantrine combined with placebo (119 children) or with 0·1 mg/kg (116), 0·4 mg/kg (116), or 0·75 mg/kg (117) primaquine base. The mean duration of gametocyte carriage was 6·6 days (95% CI 5·3-7·8) in the 0·75 mg/kg reference group, 6·3 days (5·1-7·5) in the 0·4 mg/kg primaquine group (p=0·74), 8·0 days (6·6-9·4) in the 0·1 mg/kg primaquine group (p=0·14), and 12·4 days (9·9-15·0) in the placebo group (p<0·0001). No children showed evidence of treatment-related haemolysis, and the mean maximum decrease in haemoglobin concentration was not associated with the dose of primaquine received-it did not differ significantly compared with placebo (10·7 g/L, SD 11·1) in the 0·1 mg/kg (11·4 g/L, 9·4; p=0·61), 0·4 mg/kg (11·3 g/L, 10·0; p=0·67), or 0·75 mg/kg (12·7 g/L, 8·2; p=0·11) primaquine groups.
We conclude that 0·4 mg/kg primaquine has similar gametocytocidal efficacy to the reference 0·75 mg/kg primaquine dose, but a dose of 0·1 mg/kg was inconclusive for non-inferiority. Our findings call for the prioritisation of further trials into the efficacy and safety of doses of primaquine between 0·1 mg/kg and 0·4 mg/kg (including the dose of 0·25 mg/kg recently recommended by WHO), in view of the potential for widespread use of the drug to block malaria transmission.
Wellcome Trust and the Bill & Melinda Gates Foundation.
The Lancet Infectious Diseases 11/2013; · 19.97 Impact Factor
[show abstract][hide abstract] ABSTRACT: Indoor residual spraying (IRS) with insecticide is now recommended for malaria control in high-transmission settings. However, concerns about insecticide resistance have increased. We conducted a cross-sectional household survey in high-transmission northern Uganda in two districts previously sprayed with pyrethroids before documentation of pyrethroid resistance and at least one round of carbamates and one contiguous district that was not sprayed. Parasitemia prevalence among children < 5 years of age was lower in the two IRS districts compared with the non-sprayed district: 37.0% and 16.7% versus 49.8%, P < 0.001. Anemia prevalence was also significantly lower in the two IRS districts: 38.8% and 36.8% versus 53.0%, P < 0.001. Multivariable Poisson regression models indicated that a child living in a sprayed district had a 45% and 32% lower risk of parasitemia and anemia, respectively, than a child in a non-sprayed district (P < 0.001). Carefully managed IRS can significantly reduce malaria burden in high-transmission settings.
The American journal of tropical medicine and hygiene 03/2013; · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background. Despite its primary use in children, pharmacokinetic/pharmacodynamic (PK/PD) data on dihydroartemisinin-piperaquine (DP) in young children is lacking.Methods. We conducted a prospective PK/PD study of piperaquine in 107 young children in Uganda. Samples were collected up to 28 days after 218 treatments for malaria occurring over 5 months of follow-up. Malaria follow-up was conducted actively to day 28 and passively to day 63.Results. Median day-7 capillary piperaquine concentration was 41.9 ng/mL. Low piperaquine concentrations were associated with the risk of recurrent malaria up to 42 days, primarily in those receiving trimethoprim-sulfamethoxazole (TS) prophylaxis. In children not taking TS, piperaquine concentrations were only modestly associated with the risk of recurrent malaria. However, for children on TS, associations were strong and evident for all sampling days. Day 7 concentrations ≤27.3 ng/mL were highly predictive of the risk for recurrent malaria. Notably, of 132 cases of recurrent malaria, 119 had detectable piperaquine concentrations at the time of presentation with recurrent malaria.Conclusions. These piperaquine PK/PD data represent the first in children <2 years of age. Piperaquine exposure on day 7 correlates with risk of recurrent malaria after DP treatment in children on TS prophylaxis. Interestingly, despite strong associations, infants remain at risk for malaria even in the presence of residual levels of piperaquine.
The Journal of Infectious Diseases 02/2013; · 5.85 Impact Factor
[show abstract][hide abstract] ABSTRACT: Artemisinin-based combination therapies (ACTs) and trimethoprim-sulfamethoxazole (TS) prophylaxis are important tools for malaria control, but there are concerns about their effect on gametocytes, the stage of the parasite responsible for transmission. We conducted a longitudinal clinical trial in a cohort of HIV-infected and uninfected children living in an area of high malaria transmission intensity in Uganda. Study participants were randomized to artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) for all treatments of uncomplicated malaria (N = 4,380) as well as TS prophylaxis for different durations. The risks of gametocytemia detected by microscopy in the 28 days after antimalarial therapy were compared using multivariate analyses. The risk of gametocyte detection was significantly higher in patients treated with DP compared with AL (adjusted relative risk = 1.85, P < 0.001) and among children prescribed TS prophylaxis (adjusted relative risk = 1.76, P < 0.001). The risk of gametocytemia and its potential for increasing transmission should be considered when evaluating different ACTs and TS prophylaxis for malaria control.
The American journal of tropical medicine and hygiene 02/2013; · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: In sub-Saharan Africa, malnutrition and malaria remain major causes of morbidity and mortality in young children. There are conflicting data as to whether malnutrition is associated with an increased or decreased risk of malaria. In addition, data are limited on the potential interaction between HIV infection and the association between malnutrition and the risk of malaria.
A cohort of 100 HIV-unexposed, 203 HIV-exposed (HIV negative children born to HIV-infected mothers) and 48 HIV-infected children aged 6 weeks to 1 year were recruited from an area of high malaria transmission intensity in rural Uganda and followed until the age of 2.5 years. All children were provided with insecticide-treated bed nets at enrolment and daily trimethoprim-sulphamethoxazole prophylaxis (TS) was prescribed for HIV-exposed breastfeeding and HIV-infected children. Monthly routine assessments, including measurement of height and weight, were conducted at the study clinic. Nutritional outcomes including stunting (low height-for-age) and underweight (low weight-for-age), classified as mild (mean z-scores between -1 and -2 during follow-up) and moderate-severe (mean z-scores < -2 during follow-up) were considered. Malaria was diagnosed when a child presented with fever and a positive blood smear. The incidence of malaria was compared using negative binomial regression controlling for potential confounders with measures of association expressed as an incidence rate ratio (IRR).
The overall incidence of malaria was 3.64 cases per person year. Mild stunting (IRR = 1.24, 95% CI 1.06-1.46, p = 0.008) and moderate-severe stunting (IRR = 1.24, 95% CI 1.03-1.48, p = 0.02) were associated with a similarly increased incidence of malaria compared to non-stunted children. Being mildly underweight (IRR = 1.09, 95% CI 0.95-1.25, p = 0.24) and moderate-severe underweight (IRR = 1.12, 95% CI 0.86-1.46, p = 0.39) were not associated with a significant difference in the incidence of malaria compared to children who were not underweight. There were no significant interactions between HIV-infected, HIV-exposed children taking TS and the associations between malnutrition and the incidence of malaria.
Stunting, indicative of chronic malnutrition, was associated with an increased incidence of malaria among a cohort of HIV-infected and -uninfected young children living in an area of high malaria transmission intensity. However, caution should be made when making causal inferences given the observational study design and inability to disentangle the temporal relationship between malnutrition and the incidence of malaria.
[show abstract][hide abstract] ABSTRACT: We measured virologic suppression among 34 nevirapine (NVP)-exposed HIV-infected children with median age of 8.6 months (range: 3.2-19.9) initiating NVP-based antiretroviral therapy (ART) in rural Uganda. In Kaplan-Meier analysis, the cumulative probability of virologic suppression, defined as having two consecutive HIV-1 RNA <400 copies ml(-1) by 18 months was 56%. In multivariate Cox proportional hazard modeling, the following pre-ART measurements were independently associated with an increased probability of viral suppression: increasing age [hazard ratio (HR) =1.28 per 1 month increase in age, p = 0.002], lower viral load (HR = 3.54 for HIV RNA > 7 50 000 copies ml(-1), p = 0.03) and high CD4% (HR = 6.0 for CD4% > 25, p = 0.003). These results lend additional support to the 2010 World Health Organization recommendations that protease inhibitors be used to treat NVP-exposed children, but that NVP-based ART should be initiated before the decline of CD4% to optimize outcomes in NVP-exposed children when protease inhibitors are not available.
Journal of Tropical Pediatrics 09/2011; 58(3):194-9. · 1.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: The relationship between malnutrition and malaria in young children is under debate, and no studies evaluating the association between malnutrition and response to artemisinin-based combination therapies (ACTs) have been published. We evaluated the association between malnutrition and response to antimalarial therapy in Ugandan children treated with ACTs for repeated episodes of malaria. Children aged 4 to 12 months diagnosed with uncomplicated malaria were randomized to dihydroartemisinin-piperaquine (DP) or artemether-lumefantrine (AL) and followed for up to 2 years. All HIV-exposed and HIV-infected children received trimethoprim-sulfamethoxazole prophylaxis (TS). The primary exposure variables included height-for-age and weight-for-age z scores. Outcomes included parasite clearance at days 2 and 3 and risk of recurrent parasitemia after 42 days of follow-up. Two hundred ninety-two children were randomized to DP or AL, resulting in 2,013 malaria treatments. Fewer than 1% of patients had a positive blood smear by day 3 (DP, 0.2%; AL, 0.6% [P = 0.18]). There was no significant association between height-for-age or weight-for-age z scores and a positive blood smear 2 days following treatment. For children treated with DP but not on TS, decreasing height-for-age z scores of <-1 were associated with a higher risk of recurrent parasitemia than a height-for-age z score of >0 (hazard ratio [HR] for height-for-age z score of <-1 and ≥-2 = 2.89 [P = 0.039]; HR for height-for-age z score of <-2 = 3.18 [P = 0.022]). DP and AL are effective antimalarial therapies in chronically malnourished children in a high-transmission setting. However, children with mild to moderate chronic malnutrition not taking TS are at higher risk for recurrent parasitemia and may be considered a target for chemoprevention.
Antimicrobial Agents and Chemotherapy 03/2011; 55(6):2629-35. · 4.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the protective efficacy of co-trimoxazole prophylaxis against malaria in HIV exposed children (uninfected children born to HIV infected mothers) in Africa.
Non-blinded randomised control trial
Tororo district, rural Uganda, an area of high malaria transmission intensity
203 breastfeeding HIV exposed infants enrolled between 6 weeks and 9 months of age
Co-trimoxazole prophylaxis from enrollment until cessation of breast feeding and confirmation of negative HIV status. All children who remained HIV uninfected (n = 185) were then randomised to stop co-trimoxazole prophylaxis immediately or continue co-trimoxazole until 2 years old.
Incidence of malaria, calculated as the number of antimalarial treatments per person year.
The incidence of malaria and prevalence of genotypic mutations associated with antifolate resistance were high throughout the study. Among the 98 infants randomised to continue co-trimoxazole, 299 malaria cases occurred in 92.28 person years (incidence 3.24 cases/person year). Among the 87 infants randomised to stop co-trimoxazole, 400 malaria cases occurred in 71.81 person years (5.57 cases/person year). Co-trimoxazole prophylaxis yielded a 39% reduction in malaria incidence, after adjustment for age at randomisation (incidence rate ratio 0.61 (95% CI 0.46 to 0.81), P = 0.001). There were no significant differences in the incidence of complicated malaria, diarrhoea, pneumonia, hospitalisations, or deaths between the two treatment arms.
Co-trimoxazole prophylaxis was moderately protective against malaria in HIV exposed infants when continued beyond the period of HIV exposure despite the high prevalence of Plasmodium genotypes associated with antifolate resistance. Trial registration Clinical Trials NCT00527800.
[show abstract][hide abstract] ABSTRACT: Artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are highly efficacious antimalarial therapies in Africa. However, there are limited data regarding the tolerability of these drugs in young children. We used data from a randomized control trial in rural Uganda to compare the risk of early vomiting (within one hour of dosing) for children 6-24 months of age randomized to receive DP (n = 240) or AL (n = 228) for treatment of uncomplicated malaria. Overall, DP was associated with a higher risk of early vomiting than AL (15.1% versus 7.1%; P = 0.007). The increased risk of early vomiting with DP was only present among breastfeeding children (relative risk [RR] = 3.35, P = 0.001) compared with children who were not breastfeeding (RR = 1.03, P = 0.94). Age less than 18 months was a risk factor for early vomiting independent of treatment (RR = 3.27, P = 0.02). Our findings indicate that AL may be better tolerated than DP among young breastfeeding children treated for uncomplicated malaria.
The American journal of tropical medicine and hygiene 10/2010; 83(4):873-5. · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Early cessation of breastfeeding increases morbidity and mortality of children born to HIV-infected mothers in resource-limited settings. However, data on whether breastfeeding reduces the risk of malaria in HIV-exposed and HIV-infected children is limited.
We prospectively followed 99 HIV-unexposed children, 202 HIV-exposed children, and 45 HIV-infected children in a high malaria transmission area in Uganda. All children were given insecticide-treated bednets. HIV-exposed and HIV-infected children were given trimethoprim-sulfamethoxazole prophylaxis. Malaria diagnosis was based on fever and a positive blood smear. Date of breastfeeding cessation was determined through monthly questionnaires. Associations between breastfeeding and the risk of malaria were modeled through binomial generalized estimating equations using multivariate analysis adjusting for repeated measures, age, and location of residence. Analyses were stratified according to mothers' and children's HIV status.
Breastfeeding was associated with a significantly lower risk of malaria in 6-15 months old HIV-exposed children (relative risk [RR] = 0.62; P = 0.008) and 6-15 months old HIV-infected children (RR = 0.31; P = 0.002). However, breastfeeding was not protective against malaria for >15-24 months old HIV-unexposed (RR = 1.14; P = 0.21) or >15-24 months old HIV-infected children (RR = 1.11; P = 0.75).
HIV-infected mothers should be counseled about the importance of breastfeeding and trimethoprim-sulfamethoxazole prophylaxis to protect their young children and themselves against malaria.
[show abstract][hide abstract] ABSTRACT: Artemisinin-based combination therapies are now widely recommended as first-line treatment for uncomplicated malaria. However, which therapies are optimal is a matter of debate. We aimed to compare the short- and longer-term efficacy of 2 leading therapies in a cohort of young Ugandan children.
A total of 351 children aged 6 weeks to 12 months were enrolled and followed up for up to 1 year. Children who were at least 4 months of age, weighted at least 5 kg, and had been diagnosed as having their first episode of uncomplicated malaria were randomized to receive artemether-lumefantrine or dihydroartemisinin-piperaquine. The same treatment was given for all subsequent episodes of uncomplicated malaria. Recrudescent and new infections were distinguished by polymerase chain reaction genotyping. Outcomes included the risk of recurrent malaria after individual treatments and the incidence of malaria treatments for individual children after randomization.
A total of 113 children were randomized to artemether-lumefantrine and 119 to dihydroartemisinin-piperaquine, resulting in 320 and 351 treatments for uncomplicated falciparum malaria, respectively. Artemether-lumefantrine was associated with a higher risk of recurrent malaria after 28 days (35% vs 11%; P = .001]). When the duration of follow-up was extended, differences in the risk of recurrent malaria decreased such that the overall incidence of malaria treatments was similar for children randomized to artemether-lumefantrine, compared with those randomized to dihydroartemisinin-piperaquine (4.82 vs 4.61 treatments per person-year; P = .63). The risk of recurrent malaria due to recrudescent parasites was similarly low in both treatment arms.
Artemether-lumefantrine and dihydroartemisinin-piperaquine were both efficacious and had similar long-term effects on the risk of recurrent malaria. Clinical trials registration. NCT00527800.
[show abstract][hide abstract] ABSTRACT: Artemisinin combination therapy has become the standard of care for uncomplicated malaria in most of Africa. However, there is limited data on the safety and tolerability of these drugs, especially in young children and patients co-infected with HIV.
A longitudinal, randomized controlled trial was conducted in a cohort of HIV-infected and uninfected children aged 4-22 months in Tororo, Uganda. Participants were randomized to treatment with artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) upon diagnosis of their first episode of uncomplicated malaria and received the same regimen for all subsequent episodes. Participants were actively monitored for adverse events for 28 days and then passively for up to 63 days after treatment. This study was registered in ClinicalTrials.gov (registration # NCT00527800).
A total of 122 children were randomized to AL and 124 to DP, resulting in 412 and 425 treatments, respectively. Most adverse events were rare, with only cough, diarrhoea, vomiting, and anaemia occurring in more than 1% of treatments. There were no differences in the risk of these events between treatment groups. Younger age was associated with an increased risk of diarrhoea in both the AL and DP treatment arms. Retreatment for malaria within 17-28 days was associated with an increased risk of vomiting in the DP treatment arm (HR = 6.47, 95% CI 2.31-18.1, p < 0.001). There was no increase in the risk of diarrhoea or vomiting for children who were HIV-infected or on concomitant therapy with antiretrovirals or trimethoprim-sulphamethoxazole prophylaxis.
Both AL and DP were safe and well tolerated for the treatment of uncomplicated malaria in young HIV-infected and uninfected children.
ClinicalTrials.gov: NCT00527800; http://clinicaltrials.gov/ct2/show/NCT00527800.
[show abstract][hide abstract] ABSTRACT: HIV infection increases the risk of placental malaria, which is associated with poor maternal and infant outcomes. Recommendations in Uganda are for HIV-infected pregnant women to receive daily trimethoprim-sulphamethoxazole (TS) and HIV-uninfected women to receive intermittent sulphadoxine-pyrimethamine (SP). TS decreases the risk of malaria in HIV-infected adults and children but has not been evaluated among pregnant women.
This was a cross sectional study comparing the prevalence of placental malaria between HIV-infected women prescribed TS and HIV-uninfected women prescribed intermittent preventive therapy with sulphadoxine-pyrimethamine (IPT-SP) in a high malaria transmission area in Uganda. Placental blood was evaluated for malaria using smear and PCR.
Placentas were obtained from 150 HIV-infected women on TS and 336 HIV-uninfected women on IPT-SP. The proportion of HIV-infected and HIV-uninfected women with placental malaria was 19% vs. 26% for those positive by PCR and 6% vs. 9% for those positive by smear, respectively. Among all infants, smear+ placental malaria was most predictive of low birth weight (LBW). Primigravidae were at higher risk than multigravidae of having placental malaria among HIV-uninfected, but not HIV-infected, women. Adjusting for gravidity, age, and season at the time of delivery, HIV-infected women on TS were not at increased risk for placental malaria compared to HIV-uninfected women on IPT-SP, regardless of the definition used.
Prevalence of placental malaria was similar in HIV-infected women on TS and HIV-uninfected women on IPT-SP. Nonetheless, while nearly all of the women in this study were prescribed anti-folates, the overall risk of placental malaria and LBW was unacceptably high. The population attributable risk of placental malaria on LBW was substantial, suggesting that future interventions that further diminish the risk of placental malaria may have a considerable impact on the burden of LBW in this population.