Immunité post-vaccinale contre l’hépatite B chez les enfants du Burkina Faso

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Résumé

Abstract
Introduction: Hepatitis B is a major public health problem in the
world. The routine immunization of infants against this disease has
been effective in Burkina Faso for about ten years. The purpose of this
study was to evaluate immunity against HBV in vaccinated children
after a decade of vaccination.
Methods: a descriptive cross-sectional study was conducted;
it included all children who had received at least one dose of HBV
vaccine. A child was fully vaccinated if he had received all three doses
of the vaccine. Assays for hepatitis B surface antigen (HBsAg) rates
and anti-HBs antibody (anti-HBs) have been performed with the PLC
ARCHITECT 4100. The latter threshold 10 IU/L for the title of anti-HBs
antibody was considered to define a “good immunization”. Logistic
regression was used to determine the factors influencing the degree
of immunization.
Results: 198 children were included with a sex ratio of 1.2. Low
birth weight was found in 10.40% of them. More than 30% of children
received their first dose of vaccine between three and five months.
Fully vaccinated children accounted for 89.4%. The overall prevalence
of HBsAg was 1% and that of the anti-HBs, 79.8%. Eight out of ten
children vaccinated were protected. The mean titer of the anti-HBs
was 254,5/L ± 329.1UI. A multivariate analysis showed that only age
(and thus decline compared to vaccination) was a factor significantly
associated with optimal post-vaccination protection against hepatitis
B (p = 0.011).
Conclusion: This study showed that the majority of children
acquire protective anti-HBV immunity after primary vaccination
according to the national immunization (Expanded Program of
Immunization: EPI) regimen. However, the considerable decrease in
the rate of anti-HBs after 3 years should perhaps be discussing the
relevance of a booster vaccination within the epidemiological context
and other risk factors.

Mots-clés

HBV vaccination; Immunization; EPI-Burkina Faso; children