Protective hepatitis B antibodies (Anti-HBs) after three doses of hepatitis B vaccine in a cohort of children in Riyadh, Saudi Arabia

The hepatitis B vaccine was added as the seventh primary immunogen of the Expanded Program on Immunisation (EPI) in October 1989 in the Kingdom of Saudi Arabia but the schedule was not altered. It consists of active vaccination at birth, six weeks and then six months of age without hepatitis B surface antigen (HBsAg) screening. The objective of this study was to determine the seropositivity rate of antibody to hepatitis B surface antigen (anti-HBs) after three doses of hepatitis B vaccine in children who came for pediatric check up service at Sulaiman Al-Habib Medical Center in Riyadh, Saudi Arabia. A retrospective chart review was conducted for all the children starting from January 1997 at the private medical center in Riyadh, Saudi Arabia. Anti-HBs titre equal to or higher than 10 mIU/mL is considered positive. One thousand and eight patients satisfied our criteria and were included in the study. Their age ranged between 0.75 - 18 years (mean 7.1 ± 3.7 years). Five hundred and ninety-two (58.7%) were males and 416 (41.3%) were females. Overall seropositivity rate was 83.1% with the higher rate in those younger than seven years of age (86.7%) and lower rate in those older than seven years (78.7%). The mean age of the seropositive group was significantly less than that of the seronegative group (P < 0.01) There was no difference between the rate of seropositivity between males and females. We conclude that the overall seropositivity rate in Saudi Arabia is 83%. The rate in infants following universal infant hepatitis B vaccination is acceptable. Further studies are needed in older children and adolescents.