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TRANSACTIONSOFTHEROYALSOCIETYOFTROPICALMEDICINEANDHYGIENE(2000)94,265-270
A severe epidemic of meningococcal meningitis in Nigeria, 1996
Idris Mohammed’*, Abdussalam Nasidi3, A. S. Alkali’, M. A. Garbati’, E. K. Ajayi-Obe’, Kudi A. Audu’,
Abdulmumini Usman and Suleiman Abdullahi’ Departments of ‘Medicine and ‘Microbiology, University of
Maidugwi, P.M.B. 1069, Bama Road, Maiduguri, Nigeria; Department of &ease Control and Intemanonal Health,
Federal Ministy of Health, Abuja, Nigeria; 4Epidemiologikal Unit, Kano State Ministy of Health, Kano, Nigeria; ‘Infectious
Diseases Hospital, Sabon Gari, Kano, Nigeria
Abstract
A particularly severe epidemic of meningococcal meningitis (cerebrospinal meningitis, CSM) occurred in
Nigeria between January and June 1996. There were 109 580 recorded cases and 11717 deaths, giving a
case fatalitv rate of 10.7% overall. This is the most serious enidemic of CSM ever recorded in Nigeria, and
may be thelargest in Africa this century. It took over 3 months and the combined efforts of a Nat&al Task
Force set up by the Federal Ministry of Health, the WHO, UNICEF, UNDP, Medecins Sam Front&es,
the International Red Cross and several other non-governmental organizations to bring the epidemic under
control. The main control measures centred on active treatment of infected persons, mass vaccination and
health education. The exact number of persons treated cannot be ascertained, but there were treatment
centres in almost every Local Government Area in the affected States. A study of 1577 patients admitted at
the Infectious Diseases Hospital, Kano, showed that 84% ofthose infected were aged s20 years and that, for
the first time, infants aged ~2 months were affected. Despite intervention, the case fatality rate of 9.1%
among this group of patients was similar to the nationwide figure of 10.7%. Long-acting oily chloramphe-
nicol proved highly effective in the treatment of patients, and its routine use in epidemic CSM is
recommended. Over 13 million persons were vaccinated in the course of the epidemic. For the first time,
cases of CSM were reported from States south of the ‘African meningitis belt’, suggesting an extension of the
belt. The severity of this epidemic yet again underscores the need for a clear policy regarding control
measures aimed at forestalling future epidemics. The availability of the recently developed polysaccharide-
protein conjugate vaccine should facilitate a decision on mass vaccination for the prevention of epidemic
CSM in Africa.
Keywords:
meningitis, Neisseria ;meningitidis, epidemiology, epidemic, mortality, disease control, chloramphenicol,
vaccination, Nigeria
Introduction
The first outbreak of meningococcal meningitis (cere-
brospinal meningitis, CSM) in Africa occurred in Algeria
in 1840 (CHALMERS & O’FARRELL, 19 16). Epidemics in
West Africa were reported later, in the Cape Coast in the
late 19th and early 20th centuries (WILLIAMS & WIL-
LIAMS, 1900, 1901). These epidemics ofmeningococcal
meningitis continue to occur in sub-Saharan Africa
despite the knowledge that they can be controlled by a
properly designed chemoprophylaxis regimen (VOLLUM
& GRIFFITHS, 1962; BIAKEBROUGH & GILLES, 1980),
and a well-executed immunization programme (ARTEN-
STEIN et al., 1970; WAHDAN et al., 1973; ETTORI et al.,
1977; GREENWOOD & WALI, 1980; MOHAMMED &
ZARUBA, 198 1). Sulphonamides, penicillin, chloram-
phenicol and rifampicin have been used to good effect in
reducing meningococcal carriage in the nasopharynx, a
factor in preventing outbreaks, although the potential
costs would militate against their use in co-ntrolling
eoidemics of CSM (GREENWOOD. 1999). Vaccination
appears to hold the best promise for ultimate control of
epidemic meningococcal disease. Earlier trials of menin-
gococcal vaccines produced inconclusive or disappoint-
ing results, either because the trials were not properly
conducted or because the vaccines used were poorly
immunogenic (DAVIS, 1931; RIDING & CORKHILL,
1932). Groups A & C polysaccharide vaccines developed
later were more immunogenic in adults (GOLDSCHNEI-
~~~etal., 1969; GREENWOOD etal., 1980), but less soin
infants and young children (MONT0 et &., 1973; PEL-
TOLA et al, 1977; MOHAMMED & DAMISAH. 1982). In
recent years mass vaccination using groups A & C
meningococcal polysaccharide vaccines has been carried
out in several States in northern Nigeria with fairly good
results (MOHAMMED & ZARUBA, 198 1; MOHAMMED et
al., 198‘4a, 1984b). Sustained routine mass vaccination
with currently available bivalent vaccines, backed up by
*Author for correspondence:
e-mail maiduguri-lab@who.nigeria.org
selective vaccination during outbreaks, might have pre-
vented this outbreak, or limited its scale.
Five major epidemics of CSM have occurred in nortb-
em Nigeria in the past 30 years, in 1970, 1975, 1977,
1986 and 1996. The 1996 epidemic is the severest of
them all and is the subject of this paper. It was preceded
by similar epidemics in Chad (1988), and Niger Republic
(1991,1994), both countries neighbouring Nigeria. The
same strain, Neisseria meningitid&, sero-group-A, clonal
LOUD
X11.1, was resnonsible for the outbreak in those
countries (WHO, 1995), and is the same as that which
caused epidemics in Nepal in 1983 (COCHI et al., 1987)
and Saudi Arabia in 1987 (MOORE, 1992), and may have
been introduced to Africa by pilgrims returning home
from that country. There is some evidence that this strain
of meningococcus was introduced to Nigeria from Niger
Republic through Jibia, the border town in Katsina State
which is some 30 kilometers from Maradi.
The factors responsible for the severity of this epi-
demic are not clearly known, but the outbreak occurred
in the hot, dry and dusty season when the absolute
humidity was also low. Herd immunity in the general
population was probably low since vaccination coverage
in the preceding 2 years had been low (Federal Ep’l-
demiological Unit. nersonal communication). Poor en-
vironmental condi&ns facilitated the rapid &read of the
epidemic, as the majority of those infected were of low
socio-economic status living in over-crowded, poorly
ventilated and dirtv dwellinas. The strain of meninno-
coccus responsible for the-epidemic was new to &e
region, and its virulence may have been due in part to
an inability to mount an effective immune response.
Features of the epidemic
A formal report of the outbreak was made to the
Epidemiological Unit of the Federal Ministry of Health
at the end of February 1996. However, the record books
of several Local Government health units show that cases
of meningitis had been diagnosed with increasing fre-
quency as far back as October 1995. In a rural health
centre at Jibia, a town in north-western Nigeria bordering
Niger Republic, the epidemic threshold (15 cases per
100 000 population for 2 consecutive weeks) had been
reached in November 1995.
The organism
A total of 467 cerebrospinal fluid specimens from
patients aged 3 months to 30 years (260 males, 207
females) in 6 States (Bauchi, Kaduna, Kano, Katsina,
Kebbi and Yobe) were subjected to latex agglutination
(test kits kindlv donated bv the International Red Cross).
and culture. Of these, 288*were positive on culture for G
meningitidis (173 males, 115 females); 432 (245 males,
187 females) were positive for N. meningz’tidis group A on
latex agglutination. None of the specimens was positive
for group B or C meningococcus, or Streptococcus
pneumona’ae.
Three samples were positive for Haemophi-
lus injruenzae on latex agglutination. Clonal identification
of the organism done at the National Institute of Public
Health, Oslo, Norway, by courtesy of Dr Francis Varaine
(Medecins Sam Front&es, MSF), showed that the
organism responsible for the epidemic was N. meningi-
tidis. seroaroun A clonal sub-frroun III. 1. The low
posctivity & culture (61.7%) is”moit probably due to
antibiotic self-medication before arrival in hospital, a
well-known phenomenon in Africa.
Climatic conditions
The epidemic started in January and reached its peak
in mid-April when it was extremely dry and dusty,
and the average ambient temperature (Department of
Meteorological Services, Nigeria) was 39.3”C (range
37-42°C). The relative humidity was 30.2% (range
lo-65%). The highest ambient temperature and the
lowest relative humidity were recorded in March, April
and May, at the peak of the epidemic. The situation was
compounded by the fact that most of the population of
the affected States lived in poorly ventilated, over-
crowded rooms where the internal room temperature
could rise above 45°C during daylight. The first rains
were recorded in mid-May 1996.
Dynamics
of
the epidemic
The epidemic threshold was reached in the 4th week of
February in most States, and once it had taken hold, the
outbreak spread across most ofnorthem Nigeria within 2
IDRIS MOHAMMED
ETAL.
weeks. The States most affected are those in the heart of
the African meningitis belt, namely, Katsina, Sokoto,
Kebbi, Kano, Niger, Kaduna, Jigawa, Bauchi, Yobe and
Bomo (Fig. 1). Four of these States (Bauchi, Kano,
Katsina and Kebbi) between them accounted for 8 1230
(74.1%) of the cases renorted. The attack rate ranged
&om 8 ‘to 1000 as sho& in Figure 1. States sucg as
Adamawa, Taraba, Plateau and Kwara lie just outside
the meningitis belt, and the attack rate of 21 to 200 in
these States is consistent with previous findings (MO-
HAMMED
et al., 1984a). Importantly, cases were reported
from States as far south as Ogtm, Delta, Cross River and
Enugu, several hundred kilometers from the belt.
The epidemic curve
Figure 2 shows the epidemic curve from week 4 (end of
January) to week 22 (beginning of June). A dramatic rise
in the number of reported cases began in weeks 9/10, the
epidemic reaching a peak in week 14 when 16 026 cases
were reported. This was followed by a rapid decline in the
number of cases in weeks 15 to 19, and only 25 cases were
reported in week 2 1, and none in week 22. It is of note in
T V Onset of Rains
my\ 20 1 1 1
5
X
4 5 6 7 8 9 10111213141516171819202122
Time (weeks)
Fig. 2. The meningococcal meningitis epidemic curve for Ni-
geria, 1996. Arrows indicate timing of intervention components
in relation to the epidemic curve. T, treatment; V, vaccination.
Attack rate/l 00 000
j$j@ g-20
m 21-200
m 201-500
Fig. 1. Map ofNigeria showing attackrate from meningococcal meningitis in affected States (numbered l-21) in the 1996 epidemic. 1,
Kebbi; 2, Sokoto; 3, Katsina; 4, Kano; 5, Jigawa; 6, Bauchi; 7, Yobe; 8, Borno; 9, Niger; 10, Kaduna; 11, Adamawa; 12, Kwara; 13,
Kogi; 14, Plateau; 15, Taraba; 16, Osun; 17,
Edo; 18, Enugu; 19, Cross River; 20, Ogun; 2 1, Delta.
MFJNINGOCOCCAL MENINGITIS IN NIGERIA 267
relation to the epidemic curve that therapeutic interven-
tion and mass vaccination began in weeks 9 (early
March) and 10 (mid-March) respectively, whilst the
rains began to fall in week 17 (early May).
Age and sex
na, Niger and Sokoto States had vaccinated about 20%
of the susceptible population in 1994 and 1995, but the
other States of Nigeria in the meningitis belt had hardly
vaccinated anybody. The complacency might have been
engendered by the fact that the number of cases and
deaths from CSM had remained low since 1990.
Accurate information on age and sex was available for
64 130 patients. Of these, 35 356 were male, making the
male:female (M:F) ratio 1.2: 1 (Table 1). There were 750
patients aged less than 12 months (M:F ratio 1.2:1).
Seventy-two percent of the patients were aged O-15
years (26 532 males, 19 622 females; M:F ratio 1.4: 1). A
total of 7074 patients were aged 2 30 years, and as the
age-group affected approached 30 years the M:F ratio
became unity.
Intervention to control the epidemic
Case-fatality rate
There were 109 580 reported cases and 117 17 deaths,
giving a case-fatality rate (CFR) of 1097%. A more
detailed analysis of the data from the 4 most affected
States (Table 2) shows that as the epidemic progressed
the CFR fell progressively in each of the States. The
average CFR for the 4 States fell from 22.1% in the first
10 weeks to 14.8% in the second 10 weeks and 4.8% in
the last 10 weeks of the epidemic. The overall CFR for
the 4 States (10.5%) was similar to the overall CFR of
10.7% nationwide.
The Federal Ministry of Health set up a special Task
Force (headed by one of us, I. M.) to coordinate control
activities in all the States affected. Volunteers joined the
Task Force and, together with State and Local Govem-
ments, a massive treatment and vaccination campaign
was mounted. International organizations such as the
WHO, UNICEF, and UNDP provided materials and
logistic support. Training workshops were organized
with strong support from the WHO whose country
representative took active part in the control effort.
Medecins Sans Front&es (MSF) and the International
Red Cross also provided material and logistic support,
and both aid organizations participated actively in the
vaccination exercise and therapeutic activities in the
treatment centres.
Therapeutic intervention
Pre-epidemic vaccination status
Information from the Federal Epidemiological Unit
shows that most of the States did not undertake any
significant vaccination of the population in the 2 years
preceding the outbreak. Borno, Yobe, Adamawa, Kadu-
Table 1. Age and sex distribution of cases of me-
ningococcal meningitis in Nigeria in the 1996 epi-
demic
Age-group
(years)
<l
l-5
6-15
16-29
30+
Total
Male Female M:F ratio
402 348 1.2
8610 6012 1.4
17 520 13 262 1.3
5503 5399 1.0
3321 3753 0.9
35 356 28 774 1.2
Treatment centres were established in every Local
Government Area (LGA) in the affected States early in
March. These consisted in the main of improvized
facilities in the outskirts of towns and villages, with
patients lying on unpaved bare floor. Most of these
treatment centres were manned by little-trained para-
medical staff such as community health workers. Several
of the facilities located in bigger towns and cities had
nursing staff, but few were directly managed or super-
vised by doctors. Government hospitals (including some
teaching hospitals) provided space for management of
some ofthe patients, but their contribution was marginal.
It is difficult to determine how many of the 109 580
reported cases received treatment, but most of them did.
The use of oily chloramphenicol was widely advocated
during emergency training workshops for LGA and State
health workers, but the drug (largely donated by the
WHO, MSF and the International Red Cross) was not
available in sufficient quantity. However, most patients
in Kano, Bauchi, Katsina, and Jigawa States were treated
with oily chloramphenicol with good results. The use of
this drug was limited in the other States, where more
Table 2. Number of cases, deaths and case-fatality rates (CFR) for the 4
States most affected by the 1996 Nigerian meningococcal meningitis epi-
demic
Weeks
State
Bauchi
Cases (n)
Deaths
(n)
CFR (%)
Kano
Cases (n)
Deaths (n)
CFR (%)
Katsina
Cases (n)
Deaths (n)
CFR (%)
Kebbi
Cases (n)
Deaths (n)
CFR (%)
45 (1995)- 2 (1996)- 12 (1996)- Average
1 (1996) 11 (1996) 21 (1996) CFR (%)
162 13079 5400
46 2165 452
28.4 16.6 8.4 14.3
687 13 703 10 172
160 867 345
23.3 6.3 3.4 5.6
931 9138 10858
219 1448 837
23.5 15.8 7.7 12.0
684 8550 7866
151 1265 375
22.1 14.8 4.8 10.5
IDRIS MOHAMMED
ETAL.
conventional antibiotics (benzylpenicillin and ampicil-
lin) were mainly used.
Vaccination activities
A massive vaccination campaign was mounted under
the guidance of the Federal Task Force in the 10th week
of the epidemic. This campaign had been carefully
designed in close consultation with all those actively
involved: the WHO, MSF, the Red Cross and officials of
State and Local Governments. Immediate attention was
given to the States most affected, i.e., Kano, Katsina and
Bauchi. The Federal authorities had earlier procured 12
million doses of bivalent (groups A & C) vaccines from
Pasteur-Merieux, France, and 10 million doses were
distributed to the States. The States provided other
supplies, logistic support and vaccinators, who went
village by village on bicycles, motor cycles and horse
back conducting the exercise. Members of the Task
Force went round State by State supervising the conduct
of the exercise, and providing on-the-spot training.
There was a dearth of supplies, particularly of syringes
and needles, which made it necessary to use ‘red-o-Jet
injectors (Vemitron, Carlstatdt, NY, USA) for vaccinat-
ing most of the people. These are manually operated jet
injectors which deliver 05 mL of the vaccine into the
deltoid muscle of the arm. The nozzle is placed about
1 cm from the skin surface (no contact is allowed), but
inaccurate application often results in physical contact
and bleeding, raising concerns about transmission of
infectious agents such as hepatitis viruses and HIV.
However. in Bauchi. Kano. Katsina. Tiaawa. Sokoto
and Kebbi States where MSF and &eYInternational
Red Cross conducted part of the vaccination, disposable
syringes and needles -supplied by these orgamzations
were mostlv used. Overall. 13.4 million neoule were
vaccinated *before the epidemic was brought under
control. Of these, 6.3 million were in the 4 States with
the highest number of cases (Kano, Katsina, Bauchi,
Kebbi). A total of 95 million neonle were vaccinated bv
the States, 3 million by the MSk (i.4 million in Kano, 0.8
million each in Bauchi and Katsina), and 0.93 million by
the International Red Cross ( 059 million in Jigawa, 0.17
million each in Kebbi and Sokoto). There were no
reports of any untoward reactions to the vaccine used
throughout the country. As vaccination and antibiotic
treatment progressed, the number of reported cases fell,
and the illness became milder, so that by the 16th week
the total number of reported cases nationwide had
dropped to 8750 per week, and the case-fatality rate
from 24.3% to 6.0%.
Clinical features
The main clinical features of the epidemic were stud-
ied in 1577 patients admitted at the Infectious Diseases
Hospital, Kano. The M:F ratio was 15:l. Eighty-four
percent of the patients (1325) were aged G20 years, 473
(30%) were aged 6-10 years, and, significantly, 300
(19%)
were aged O-5 years, among whom were infants
aged ~2 months. Treatment with antibiotics was given to
1544 patients, of whom 1404 recovered and 140 died
(CFR 9.1%). A total of 1243 natients were treated with a
single injec’tion of oily chloramphenicol-10 10 with
Tifomycine (Roussel), 233 with Astrapin (Pharmazeu-
tische Praparate Dr Klaus Hoffman GmBH & Co.
KG)-of whom 1118 recovered and 125 died (CFR
10.1%). Of the remainder, 146 patients received oily
chloramphenicol plus benzylpenicillin (CFR 6.5%), 124
received benzylpenicillin alone (CFR 98%), and only 3 1
were treated with ampicillin alone (CFR 17.9%). An
analysis of the age-specific CFRs among those treated
with oily chloramphenicol (Fig. 3) shows that the highest
CFR was in those aged > 3 1 years (CFR 19.6%), and the
lowest (CFR 5.4%) was in those aged 11-15 years and
26-30 years. The CFR among patients aged O-5 years
was 12.4%. Mortality was highest among patients who
presented with meningococcaemia and circulatory fail-
ure.
Discussion
This epidemic of meningococcal meningitis is by far
the severest in recorded history in Nigeria, and may well
be the largest in Africa this century. It was caused by A?
meningitidis,
serogroup A, clonal sub-group III. 1. Several
factors may have contributed to the scale and severity of
the epidemic, among them low herd immunity as a result
of non-vaccination. The socio-economic circumstances
of Nigerians had deteriorated so much in the preceding
10 years that the living conditions at the time of the
outbreak were highly conducive to the rapid spread of
epidemics such as the one that occurred. The climatic
conditions must also have contributed to the spread since
temperatures were as high as 45°C the atmosphere dry
and dusty, and the absolute humidity very low. Whether
these effects are attributable to the
El
Nirio phenomenon
remains open to speculation. The particular strain of N.
meningitidis
responsible for the epidemic (serogroup A,
clonal sub-group 111.1) was new to Nigeria, and its
virulence must have had an important bearing on the
severity of the outbreak.
The exact scale of this epidemic is unknown, since only
a proportion of families take their ill relatives to hospital
during outbreaks, either because of ignorance or for fear
of being stigmatized. The reported figure of 109 580
0
o-5
6-10 11-15 16-20 21-25 26-30 31+
Age-group (years)
Fig. 3. Outcome of treatment of meningococcal meningitis with oily chloramphenicol by age-group (Nigeria, 1996).
MENINGOCOCCAL MENINGITIS IN NIGERIA
269
cases is thus only the tip of the iceberg, as under-
reporting is common (GREENWOOD, 1999). Several
observers believe that to get nearer the true figure the
number of reported cases should be multiplied by a factor
of 10 at least. The same applies to the number who died.
During visits to States and local governments we saw
several mass graves containing hundreds of bodies of
victims who were buried secretly.
Several features of this epidemic point to a change in
the clinical and epidemiological pattern of CSM in
Africa. The age-group affected most in previous African
epidemics was 5-15 years (BELCHER et al., 1977;
GREENWOOD et al.. 1979). In this enidemic a substantial
number of childrenaged i5 years were affected, and 750
were aged C 1 year, some of them infants of C2 months. A
similarnumber of patients aged 5 16 years was recorded,
with 7074 axed 230 vears. The reasons for this widening
of the age-groups affected are not clear, but the reported
virulence of the clonal sub-group III.1 strain of the
meningococcus may have contributed to some extent.
The overall male to female ratio is consistent with
previous findings, but it is interesting that the ratio
among patients aged a-16 years was unity. This may
indicate that men and women of this age-group lead
similar lifestyles which exposes them to infection equally.
It is not certain why the epidemic extended southwards
outside the traditional meningitis belt, but the fact that
cases of CSM were reported from States as far south as
Delta, Ogun and Cross River suggests that a redefinition
of the African meningitis belt at this time might be in
order.
The epidemic curve followed a similar pattern to
previous ones, but intervention by way of treatment of
cases and mass vaccination (see timing in Fig. 2) helped
in dramatically reducing the number of cases and deaths
between weeks 16 and 19. The onset of the first rains led
to termination of the epidemic, as usual (GREENWOOD,
1999). Although the epidemic was not reported to the
Federal health authorities until February, cases sugges-
tive of an impending outbreak were recorded as early as
November 1995 in a town bordering Niger Republic.
This suggests that in all probability the organism was
imported from that neighbouring country since the same
strain of the meningococcus was responsible for an
earlier epidemic there (RLTMEIJER, 1996), which was
itself preceded by others in Nepal, India and Saudi
Arabia (MOORE
et
al., 1989). The epidemic curve also
illustrates the degree of failure of the surveillance system
in Nigeria, where an epidemic preparedness and re-
sponse mechanism has failed to take off properly.
The response to antibiotic therapy was quite good.
The results of this studv show that treatment with a single
injection of oily chloramphenicol (Tifomycine or A&a-
pin) was highly effective in this epidemic. This observa-
tion confirms earlier findings (REY
et
al., 1975; WAU
et
al., 1979; PECOUL
et
al., 199 l), and represents a major
advance in the management of epidemic meningococcal
meningitis in Africa, since little-trained personnel can be
engaged to render treatment during epidemics. There
were 146 patients who failed to show adequate response
to oily chloramphenicol, but there was no evidence from
this study to suggest the development of resistance to the
drug. Rather, we feel that the inadequate response was
due to the fact that the patients were unsuitable for
treatment with this agent, as shown by the prompt and
satisfactory response to benzylpenicillin given as substi-
tute. Oily chloramphenicol has now fully established
itself as the cornerstone of therapeutic intervention in
epidemic meningococcal disease, and its routine use is
highly recommended.
The morbidity and mortality in this epidemic were
broadly similar to those in previous epidemics in Africa
(BWALA
et
al., 1989; GREENWOOD, 1999), but are
almost certainly underestimated because many septicae-
mic patients die before reaching hospital (GREENWOOD
et
al., 1987). There were several reports, confirmed by
members of the task force, of people burying their dead
secretly within compounds or in make-shift burial
grounds. Despite these observations, the intervention
measures during the epidemic must have contributed to
the low morbidity and mortality. Vaccination with
groups A and C vaccines has been effective in controlling
epidemics of CSM when undertaken very early (GREEN-
WOOD & WALI, 1980; MOHAMMED & ZARUBA, 1981;
BINKIN 8z BAND, 1982), despite the fact that the
currently available bivalent (groups A & C) vaccines
are poorly immunogenic, particularly in younger chil-
dren (MONTO
et
al., 1973; PELTOLA
et al.,
1977),
because polysaccharide antigens are T-cell independent.
The recent development of polysaccharide-protein con-
jugate vaccines which are already undergoing trial is
believed to be a major advance in the control of epidemic
meningococcal disease because they induce strong im-
munity in young infants, as well as long-lasting T-cell-
dependent immunological memory (GREENWOOD,
1999).
An important problem of mass vaccination in Africa is
the inadequate supply of syringes and needles, necessi-
tating the use of ‘red-o-Jet injectors for vaccination, as
happened during this epidemic. We may never know how
many infectious agents (including hepatitis B and C
viruses and HIV) were transmitted as a result of using:
these injectors, but clearly their use must be stopped ai
soon as practicable. It has also been observed that mass
vaccination after an outbreak is unlikely to reduce the
number of epidemic cases by more than half (HAELTER-
MAN
et
al., 1996; VARAINE
et
al., 1997). This observation
underscores once again the need for a definite policy on
mass vaccination to prevent epidemics of CSM in Africa.
Proper coordination among all the countries within the
meningitis belt is necessary, to ensure successful control
of epidemics in the region. The financial burden on
countries in the region is likely to be high, but mass
vaccination need not be undertaken yearly, since several
trials have shown that adequate antibody responses are
induced by these vaccines (GOLDSCHNEIDER
et al.,
1969; GREENWOOD
et
al., 1980) which may remain high
for up to 4 years in persons aged 35 years (MOHAMMED
et
al., 1984b). Thus mass vaccination may need to be
carried out only every 3 years.
Acknowledgements
We gratefully acknowledge the valuable contributions of all
those who volunteered to work with
the Task Force in control-
ling this epidemic. We are particularly grateful to the WHO
(Nigeria) and Dr E. K. Njelesani who provided vaccines,
antibiotics, syringes and needles, as well as ‘Ped-o-Jet’ injectors.
The WHO also organized workshops for State and local
Government health personnel during the epidemic. The UNDP
and UNICEF provided material and logistic support. The MSF
and International Red Cross supplied vaccines, oily chloram-
phenicol, syringes and needles, and also actively participated in
the vaccination campaign and treatment of patients. The
Federal Ministry of Health urovided most of the vaccines. some
antibiotics, sv&aes and needles. ‘Ped-o-let’ iniectok. and
logistic suppdrt. We are grateful to’the Kano”State ijovemment
for accommodating members of the Task Force, and to the other
State Governments we visited for their hospitality.
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Received 9 August 1999; revised 27 October 1999; accepted
for
publication 17 November 1999
