Low‐dose vaccination against hepatitis B in children: One‐year follow‐up

Publisher Website
Google Scholar
Abstract
Six hundred forty‐three children, negative for markers of hepatitis B virus (HBV) infections. were given three × 2‐μg doses of Merck, Sharp and Dohme (MSD) plasma derived hepatitis B vaccine (H‐B‐Vax) at monthly intervals. Twelve months after the first dose of vaccine, antibody to hepatitis B surface antigen (anti‐HBs) was detected in 89% of children by radioimmunoassay (RIA) and in 83% by enzyme immunoassay (EIA). Seroconversion rates and anti‐HBs titres were significantly greater in 1‐4‐year‐olds than in older children (p < 0.01). Eighteen children with no anti‐HBs or other markers of HBV at this time were given 10 pg of vaccine and tested one month later. Seventeen developed anti‐HBs. 12 at levels consistent with an anamnestic response. Forty‐nine HBV‐marker‐negative children seroconverted for antibody to hepatitis B core antigen (anti‐HBc) in the 8‐month period before or the 12–month period following vaccination. Forty‐six of these children were positive for anti‐HBs, and one has been confirmed as a chronic carrier of hepatitis B surface antigen (HBsAg). Three cases of clinical hepatitis B in children have been seen in the community since the vaccination programme began. Two of these were amongst the estimated 5% of children who were not vaccinated. The third was in a vaccine and occurred 4½ months after the last dose of vaccine. These findings suggest that under the conditions of this programme, three intramuscular doses of 2 μg H‐B‐Vax given at monthly intervals provided effective protection for most children for at least 24 months, especially younger children who are at greatest risk of becoming HBsAg carriers.