Efficacy of primary hepatitis B immunization in children with acute lymphoblastic leukemia.

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) carry a high risk of hepatitis B virus (HIV) infection. The present study was conducted to see if prior routine hepatitis B vaccine received as a part of national immunization program could prevent HBV infection in these children.

METHODOLOGY

Ninety-six children with ALL were screened for HBV. Children were divided into three groups according to their initial HBV serology; previously vaccinated children (Group I) (n=34) previously unvaccinated and seronegative children (Group II) (n=56),and unvaccinated but HBsAg negative and anti-HBs positive children (group III) (n=6). Sixty-seven of 96 (69.7%) children received vaccination. The schedule was initiated during the third month of maintenance therapy and each course consisted of three doses given at one month interval.

RESULTS

Anti-HBs seroconversion following the first course of three doses of hepatitis B vaccination in group I, II and III was 57%, 33% and 100%, respectively. It increased to 97% in Group I, 62.5% in Group II, 100% in Group III. HBsAg positivity was found in 11 children (11.5%) and all of them developed chronic hepatitis B. Ten of them were in Group II whereas only one child was in Group I (P<0.04).

CONCLUSION

This data reveals that routine HBV vaccination within the national immunization program plays an important role in decreasing subsequent hepatitis B infection in children with ALL.