Credit: RF._.studio / Pexels

Hepatitis B virus (HBV) vaccination practices beginning shortly after birth can go a long way toward reducing transmission for African countries.¹

A team, led by Afifa Ansari, BSc, MRC Centre for Infectious Disease Analysis, School of Public Health, Imperial College London, estimated the risk of early horizontal transmission in pediatric patients of hepatitis B surface antigen (HBsAg)-negative mothers in sub-Saharan Africa stratified according to the vaccination schedule.

“One of the incremental benefits of a universal HepB-BD strategy compared with a selective one is that it might also protect children born to HBsAg-negative mothers from early horizontal transmission before receiving their first dose of HepB3 at the age of 6–8 weeks,” the authors wrote. “However, the risk of infection for children born to HBsAg-negative mothers in this early period of life (ie, early horizontal transmission) has not been formally assessed.”

HBV in Africa

Sub-Saharan Africa is highly endemic for HBV, with the majority of the population exposed during childhood during vertical or horizontal transmission. While all countries in Africa now provide a three-dose infant hepatitis B vaccination beginning at age 6-8 weeks, only about 33% of African countries have introduced birth dose (HepB-BD) vaccines.

By adding birth doses, investigators believe they can prevent vertical transmission. However, its effectiveness in preventing horizontal transmission compared to three-dose infant vaccination alone is not currently known.

In the systematic review and meta-analysis, the investigators searched various journals from inception to Oct. 24, 2022 for studies on HBsAg or HBV DNA or both, in children aged 0-5 years of HBsAg-negative mothers.

However, they excluded studies if only children were tested at birth.

The investigators sought primary outcomes of the risk of HBV infection in children of HBsAg-negative mothers, stratified by vaccination schedule. The schedule was either no vaccination, first dose at 6-8 weeks, or first dose at birth.

The team then pooled the child risks of HBsAg or HBV DNA-positivity from age 0-5 years using a random-effect meta-analysis using a generalized linear mixed model.

Vaccination Schedules

Overall, they identified 8856 articles and 27 studies evaluating 10,003 children of HBsAg-negative mothers were included.

The results show a pooled risk of infection of 6.16% (95% confidence interval [CI), 3.05-12.04; n = 155) in the no vaccination group, compared to 0.21% (95% CI, 0.04-1.15; n = 10) in children who received their first dose at 6-8 weeks and 0.05% (95% CI, 0.00-1.32; n = 3) in children who received their first dose at birth.

However, the difference was not statistically significant in children who received their first dose at 6-8 weeks and children who received their first dose at birth after they adjusted for the study period, region, and maternal HIV status (test of moderators P = 0.37).

“In children of HBsAg-negative mothers, the risk of infection might be minimal even with the vaccination starting at 6–8 weeks, without clear additional benefit from HepB-BD,” the authors wrote. “When births take place at home and timely administration of HepB-BD is challenging, antenatal HBsAg screening and selective HepB-BD might allow efficient allocation of resources to mother and child pairs at high risk compared with universal HepB-BD.”

References:

Ansari, A., Vincent, J. P., Moorhouse, L., Shimakawa, Y., & Nayagam, S. (2023). Risk of early horizontal transmission of hepatitis B virus in children of uninfected mothers in sub-Saharan africa: A systematic review and meta-analysis. The Lancet Global Health, 11(5). https://doi.org/10.1016/s2214-109x(23)00131-6