A commercially available vaccine made in Sacharomyces cerevisea by genetic engineering, containing HBsAg without pre-S components is a sterile suspension containing the major surface antigen of the hepatitis B virus, as per the manufacturer's manual. It has been shown to be immunogenic and safe, but 5-10% of healthy people do not respond or, respond with low antibody levels only, even after taking 3 doses(14). The factors which adversely affect the antibody response include, the site and route of injection, sex, advancing age, being overweight, immunosuppression and ethinicity(4).

Hepatitis B virus surface protein has three immunogenic regions 'namely pre-S1, pre-S2 and S regions. Several studies indicate that the inclusion of the pre-S components, in experimental recombinant vaccine, augments the hepatitis B surface antibody response(4).

A recent letter to the editor(5) formed the stimulus for the research question "is the antibody titre to HBsAg achieved up to the protective range in infants for whom this vaccine is available and is recommended by lAP" Antibody levels >100 IU/L is considered protective(4). A baseline information regarding the antibody titres in the subjects who attended the Immunization Centre was obtained in 1997.

This study was done over a 6 month period from July to December 1997. Out of the 58 children who had completed the three doses of vaccination, only 14 children were able to afford the cost of the test (Anti HBs) and they, therefore formed the study group. The age of the children ranged from 6 months to 10 years. The vaccine used was a commercially available Hepatitis B vaccine. Antibody levels (Anti HBs) were measured one week after giving the 3rd dose of the vaccine. This was done in two laboratories by quantitative ELISA method. We found that all the 14 children in the study group had antibody levels well above the protective range (>1000 IU/L) which were induced by the currently available vaccine even without the inclusion of the pre-S component.

Vedavati Subramanyam,
Shanti Ramesh,
The CHILDS Trust Hospital,
12-A Nageswara Road,
Nungambakkam,
Chennai 600 034,
India.
 

1. Dienstag JL, Werner BG, Polk BF, Syndman DR, Graven DE, Platt R., Hepatitis B vaccine in health care personnel: Safety, immunogenicity and indicators of efficacy. Ann Inter Med 1984; 101: 34-40.

2. Graven DE, Awdeh ZI, Kunches LM, Yunis EJ, Dienstag JL, Werner BG. Non-responsiveness to Hepatitis B vaccine in health care workers. Ann Inter Med 1986; 105:356-360.

3. Wood RC, Mac Donald KL, White KE, Hedberg CW, Hanson M, Osterholm MT. Risk factors for lack of detectable anti- body response following Hepatitis B vaccination of Minnesota Health Care workers. JAMA 1993; 270: 2935-2939.

4. Zuckerman JN, Sabin C, Craig PM, Williams A, Zuckerman AJ. Immune response to anew Hepatitis B vaccine in healthcare workers who had not responded to standard vaccine: Randomized double blind dose-response study. BMJ 1997; 314: 329- 333.

5. Balasubramaniam K. No seroconversion after Hepatitis B immunization. Indian Pediatr 1997; 34: 555-556.