Antibody Response to Hepatitis B Immunization in Infants Born to HIV-Infected Mothers
PIMOLRAT THAITHUMYANON,M.D.*, SANTI PUNNAHITANANDA, M.D.*, PRAMOTE PRAISUW ANNA, M.D.*, USA THISYAKORN, M.D.*, KIAT RUXRUNGTHAM, M.D.**
Affiliation : * Department of Pediatrics, **Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Objectives : To determine the antibody response of hepatitis B immunization begun at birth in HIV -1 exposed infants.
Design : Prospective, clinical trial. Site : King Chulalongkom Memorial Hospital, Bangkok, Thailand.
Materials and Methods : Seventy six infants born to HIY -1 seropositive mothers, who were not hepatitis B carriers, received three 10 microgram doses of recombinant DNA hepatitis B vac cine (Engerix B, Smith Kline, Belgium) in a 0, 1 and 6 month schedule. The first dose was given at birth. Serum hepatitis B surface antibody (Anti -HBs) was measured at age 3, 9 and 12 months. Anti-HBs levels were determined by enzyme-linked immunoassay using the commercial kits (AUSAB EIA diagnostic kits, Abbott Laboratories, Chicago, USA) Antibody titer ~10miU/ml was defined as seroconversion. HIY infection was diagnosed by a positive test of HIV antibody at age ~18 months and/or by positive test of HIY polymerase chain reaction at age ~3 months.
Results : There were 14 HIV-1 infected (group 1) and 62 HIY-1 non infected (group 2) infants enrolled in this study. Anti-HBs titers of group 1 infants were significantly lower than those of groups 2 infants at both 3 and 6 months after the 3'd dose of vaccine, (Mann Whitney U test, p=0.019 and 0.001 respectively). Ten infants in group 1 and 57 infants in group 2 had anti-HBs titer ~10 miU/ml. Their peak antibody titers were also noted at both 3 and 6 months after the 3'd dose of vaccine. Seroconversion rates were 71.4 per cent and 91.9 per cent in group 1 and 2 infants respectively, (p<0.05). Among the infants who had blood tests performed at age 12 months or 6 months after the 3'd dose of vaccine, anti-HBs titers declined in approximately 50 per cent of both groups of infants. There was a significantly higher percentage of seroconverters in group 1 who lost their protective titers than those in group 2, (p<0.001).
Conclusion : The results in this study suggested that HIV -1 infected infants have poor antibody response to hepatitis B immunization and the protection was less durable. A fourth dose of vaccine at 6 months after the 3'd dose may be necessary.
Keywords : Anti HBs, Hepatitis B Vaccine, HIV Infected Infants, Seroconversion
