Metrics details. Gambian infants were not routinely vaccinated against hepatitis B virus HBV before During —90 the Gambia Hepatitis Intervention Study GHIS allocated , infants, by area, to vaccination or not and thereafter all infants were offered the vaccine through the nationwide immunisation programme. During —08, young adults born during the GHIS were recruited from 80 randomly selected villages and four townships.
HBsAg-positive samples each with two age- and sex-matched HBsAg-negative samples underwent liver function tests. In addition, children born since nationwide vaccination in were tested for HBsAg. Statistical analyses ignore clustering. Comparing fully vaccinated vs unvaccinated participants, anti-HBc was The prevalence of antibodies to hepatitis C virus was low 0.
Infant HBV vaccination achieves substantial protection against chronic carriage in early adulthood, even though approximately a quarter of vaccinated young adults have been infected. This protection persists past the potential onset of sexual activity, reinforcing previous GHIS findings of protection during childhood and suggesting no need for a booster dose. Nationwide infant HBV vaccination is controlling chronic infection remarkably effectively.
Approximately 60 million people in Africa are chronically infected with HBV, mostly acquired perinatally or in early childhood [ 3 , 4 ]. A safe, effective vaccine consisting of the HBV surface antigen HBsAg was introduced in the s, although coverage was initially limited by cost [ 5 ].
Universal infant vaccination against HBV is now recommended, and over the past decade three-dose coverage of infants has increased greatly across low and middle income countries.
