SEROPREVALENCE OF POLIOVIRUS ANTIBODIES AMONGST CHILDREN IN ZARIA, NORTHERN NIGERIA

Abstract

BACKGROUND: Poliomyelitis is endemic in Nigeria, especially in Northern Nigeria
where there is continuous endemic transmission of WPV1 and 3 and cVDPV2 resulting in
high number of cases of children with AFP. The seroprevalence of antibodies to polio
serotypes which can be used to assess the degree of protection and effectiveness of the
vaccine against poliomyelitis, is unknown.

OBJECTIVE: The main aim is to determine the seroprevalence of poliovirus antibodies
types 1, 2 and 3 in children aged 1-10 years in Zaria.

METHODS: A descriptive, cross sectional, community based study was undertaken in
Zaria, North Western Nigeria between 2008 to 2009. Two hundred and sixty-four (264)
children aged 1-10 years were enrolled from two local governments in Zaria by multistage
random sampling method. Demographic data and immunization history were retrieved
from parents and caregivers by an interviewer administered questionnaire. Neutralising
antibody titres to polioserotypes I, II and III were assayed according to the WHO Manual
for the virological investigation of polio. Antibody titres > 1:8 was considered positive.

RESULTS: Boys made up 60.2% of the 264 children studied and the mean age was
6.25years. Most of the children 173(65.5%) were partially immunized against polio,
75(28.4%) were fully immunized while 16(6.1%) had never been immunised.
Seropositivity to all polio serotypes was 55.3% (86.4%, 76.1% and 77.3% of children
were seropositve to the P1, P2 and P3 polioserotypes respectively). Five (1.9%) of
children had no antibodies to all the three polioserotypes. The lowest titres were found in
children aged 1 – 5 years who had lower polio antibody seroprevalence and antibody
titres. Polio antibody seropositivity had a positive correlation with higher socioeconomic
status reflected by fathers occupation and education.

CONCLUSION: Seroprevalence to polio virus serotypes though lower than that found in
developed countries was higher than the values found in previous studies done in Nigeria.
The use of more immunogenic vaccines together with further improvements in programme
quality and sustained support by traditional, religious and political leaders could provide
the necessary immune booster to make polio eradication in Nigeria a reality.

SEROPREVALENCE OF POLIOVIRUS ANTIBODIES AMONGST CHILDREN IN ZARIA, NORTHERN NIGERIA