By C. Vidyashankar, MD

DELHI (Reuters Health) Oct 11 - There may not be a need for universal vaccination of Indian children against hepatitis A, as a vast majority develop protective antibodies by 10 years of age, researchers from India report in the September Bulletin of the World Health Organization.

Improvement in standards of living has led to a decreased prevalence of protective antibodies among children in various parts of the world. The result is an increased predisposition to severe forms of hepatitis A, but this mainly occurs in adults, Dr. Yogesh Batra and colleagues from the All India Institute of Medical Sciences in Delhi note.

The paucity of specific data on hepatitis A seroprevalence in Indian children prompted the investigators to undertake a study of 500 school children between the ages of 10 and 17 years. The researchers tested for anti-hepatitis A antibodies using enzyme-linked immuno-sorbent assay (ELISA). A detailed clinical and biochemical evaluation was also conducted.

Antibodies to hepatitis A were detected in 486 children (97.2%), indicating exposure to the virus, the researchers report. Anti-hepatitis A seroprevalence was 98.6% in children aged 10-12 years, 94.8% in children aged 13-14 years and 98.3% in children aged 15-17 years. There was no difference in anti-hepatitis A seroprevalence between boys and girls, Dr. Batra and colleagues report.

A decline in the anti-hepatitis A seroprevalence among children is likely to result in an increase in incidence of hepatitis A infection among adults, Dr. Batra and colleagues warn. However, the incidence of hepatitis A in their hospital has more or less remained static between 1992 and 2000, so it is likely that anti-hepatitis A seroprevalence has changed little over the same period, the investigators believe.

Similar results have been noted in other developing countries, where improvements in living conditions have not translated into a decline in the anti-hepatitis A seroprevalence, Dr. Batra comments.

Thus, in endemic countries like India, where "exposure to hepatitis A virus is virtually universal" among children and the incidence of hepatitis A infection among adults has remained static, "mass vaccination against hepatitis A virus may not be cost-effective" or necessary, the Delhi team asserts.

Bulletin of the World Health Organization 2002;80:728-731.

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