HBV immunization and vaccine coverage among hospitalized children in Cameroon, Central African Republic and Senegal: a cross-sectional study

Abstract

BackgroundHepatitis B is a major health concern in Africa. The vaccine against hepatitis B virus (HBV) was introduced into the Expanded Programme on Immunization (EPI) of Cameroon and Senegal in 2005, and of CAR (Central African Republic) in 2008. A cross-sectional study was conducted to assess HBV immunization coverage following the vaccine’s introduction into the EPI and factors associated with having been vaccinated.MethodsAll hospitalized children, regardless of the reasons for their hospitalization, between 3 months and 6 years of age, for whom a blood test was scheduled during their stay and whose condition allowed for an additional 2 mL blood sample to be taken, and who provided the parent’s written consent were included. All children anti-HBs- and anti-HBc + were tested for HBsAg.Vaccination coverage was assessed in three different ways: immunization card, maternal recall and serologic anti-HBs profile.Results1783 children were enrolled between April 2009 and May 2010. An immunization card was only available for 24 % of the children. The median age was 21 months.Overall HBV immunization coverage based on immunization cards was 99 %, 49 % and 100 % in Cameroon, CAR and Senegal, respectively (p < 0,001). The immunization rate based on maternal recall was 91 %, 17 % and 88 % in Cameroon, CAR and Senegal, respectively (p < 0,001). According to serology (anti-HBs titer ≥ 10 mUI/mL and anti-HBc-), the coverage rate was 68 %, 13 % and 46 % in Cameroon, CAR and Senegal, respectively (p < 0,001). In Senegal and Cameroon, factors associated with having been vaccinated were: mother’s higher education (OR = 2.2; 95 % CI [1.5–3.2]), no malnutrition (OR = 1.6; 95 % CI [1.1–2.2]), access to flushing toilets (OR = 1.6; 95 % CI [1.1–2.3]), and < 24 months old (OR = 2.1; 95 % CI [1.3–3.4] between 12 and 23 months and OR = 2.7; 95 % CI [1.6–4.4] < 12 months). The prevalence of HBV-infected children (HBsAg+) were 0.7 %, 5.1 %, and 0.2 % in Cameroon, CAR and Senegal, respectively (p < 0.001).ConclusionsAssessing immunization coverage based on immunization cards, maternal recall or administrative data could be usefully reinforced by epidemiological data combined with immunological profiles. Serology-based studies should be implemented regularly in African countries, as recommended by the WHO. Malnutrition, lack of maternal education and poverty are factors associated with vaccine non-compliance. The countries’ vaccination programs should actively address these problems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1000-2) contains supplementary material, which is available to authorized users.

A decision analytic model for prevention of hepatitis B virus infection in Sub‐Saharan Africa using birth‐dose vaccination

“…This discrepancy would have a minimal effect in many Sub-Saharan countries because approximately 90% of all infants successfully complete the pentavalent vaccine series. However, it is a potential issue for countries in which the completion rates are just 13%–30% [12, 13]. For countries with low pentavalent vaccine completion rates, use of the birth-dose HBV vaccine might increase the overall HBV immunogenicity of incomplete vaccine series and offer increased cost effectiveness.…”

The potential impact of the demographic transition in the Senegal-Gambia region of sub-Saharan Africa on the burden of infectious disease and its potential synergies with control programmes: the case of hepatitis B

“…Our baseline vaccination scenario was designed to approximate the Senegal situation in view of its possible larger relevance as: (1) The Gambia could be considered a special case due to the work of The Gambia Hepatitis Intervention Study [33], (2) the Senegal population is many times the size of its neighbour, (3) in common with many other countries in SSA, in Senegal the lack of availability of monovalent HBV vaccine prevented the implementation of universal vaccination at birth [34]. Thus, in our baseline scenario, vaccination is administered to children aged 3.5 months, with effective coverage of 46% [34] and 2005 as year of introduction of the vaccine into the Expanded Programme on Immunisation [34].…”

“…Thus, in our baseline scenario, vaccination is administered to children aged 3.5 months, with effective coverage of 46% [34] and 2005 as year of introduction of the vaccine into the Expanded Programme on Immunisation [34]. Alternative scenarios were considered including higher coverage levels (55% and 75%) as well as the possibility of vaccination at birth to prevent vertical transmission.…”

Hepatitis B treatment eligibility in West Africa: Uncertainties and need for prospective cohort studies

“…Hepatitis B virus (HBV) infection is highly endemic in sub‐Saharan Africa (SSA) and bears a high burden of liver disease . Despite the availability of an efficient vaccine against HBV infection, universal access to this prevention strategy is challenging in SSA . While HBV therapy is still out of reach for most HBV‐infected individuals globally, progress towards universal access to these drugs is underway.…”