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Published on: May 16, 2012
HBV immunization and vaccine coverage among hospitalized children in Cameroon, Central African Republic and Senegal:
Claudine Bekondi1, Roberta Zanchi2, Abdoulaye Seck3
1Laboratoire des Virus Oncogènes, Institut Pasteur de Bangui, rue Pasteur, BP 923, Bangui, République Centrafricaine. claudinebekondi@yahoo.fr.
Insights
Hepatitis B virus (HBV) immunization coverage in African countries varied significantly by assessment method, with serology revealing lower rates than immunization cards or maternal recall. Factors like maternal education and socioeconomic status influenced vaccination compliance.
Area of Science:
- Public Health
- Immunology
- Epidemiology
Background:
- Hepatitis B virus (HBV) poses a significant health challenge in Africa.
- The HBV vaccine was integrated into the Expanded Programme on Immunization (EPI) in Cameroon and Senegal in 2005, and the Central African Republic (CAR) in 2008.
- A study was conducted to evaluate HBV immunization coverage and associated factors post-vaccine introduction.
Purpose of the Study:
- To assess hepatitis B virus (HBV) immunization coverage in Cameroon, CAR, and Senegal.
- To identify factors associated with HBV vaccination compliance among children.
- To compare different methods of assessing immunization coverage.
Main Methods:
- A cross-sectional study enrolled 1783 hospitalized children aged 3 months to 6 years.
- Vaccination coverage was assessed using immunization cards, maternal recall, and serological markers (anti-HBs and anti-HBc).
- HBsAg testing was performed on children with specific anti-HBs and anti-HBc profiles.
Main Results:
- Immunization card data showed high coverage (99-100%) in Cameroon and Senegal, but low coverage (49%) in CAR.
- Maternal recall indicated higher coverage (88-91%) in Cameroon and Senegal, but only 17% in CAR.
- Serological assessment revealed significantly lower coverage rates: 68% in Cameroon, 13% in CAR, and 46% in Senegal.
- Factors associated with vaccination in Cameroon and Senegal included higher maternal education, absence of malnutrition, access to sanitation, and younger age.
- Prevalence of active HBV infection (HBsAg+) was 0.7% in Cameroon, 5.1% in CAR, and 0.2% in Senegal.
Conclusions:
- Immunization card and maternal recall data may overestimate hepatitis B virus (HBV) vaccination coverage.
- Serological studies are crucial for accurate assessment of HBV immunization coverage in African nations.
- Addressing malnutrition, maternal education, and poverty is essential for improving vaccine compliance.
Background:
Hepatitis 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.
Methods:
All 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.
Results:
1783 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).
Conclusions:
Assessing 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.