Public Health

Hepatitis A rates at new low since vaccine program begun in US

Last Updated: 2005-07-12 16:00:22 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Hepatitis A incidence has fallen to a historic low since routine hepatitis A vaccination of children was implemented in the US in 1999, according to a report in the Journal of the American Medical Association for July 13.

Since 1996, hepatitis A vaccination has been advised for at-risk individuals, such as men who have sex with men and illicit drug users. In 1999, this recommendation was extended to children living in 11 states with the highest incidence of disease. In 6 additional states with above average rates, it was advised that hepatitis A vaccination be considered for children.

In the present study, Dr. Annemarie Wasley, from the Centers for Disease Control and Prevention in Atlanta, and colleagues evaluated hepatitis A cases that were reported to the National Notifiable Disease Surveillance System since 1990.

Between the early/mid 1990s and 2003, overall hepatitis A rates fell 76% to reach an all time low -- 2.6 cases per 100,000. The previous nadir, 9.1 cases per 100,000, occurred in 1992.

The drop in hepatitis A rates in vaccinating states was 88%, whereas the reduction elsewhere was 53%, the investigators point out. Rates among children fell by 87%, while those among older subjects fell by 69%.

In the early/mid 1990s, cases from vaccinating states accounted for 65% of the total disease burden, the authors note. By 2003, however, cases from such states represented only 33% of the national total.

The proportion of hepatitis A cases involving children fell from 35% to 19%, the report indicates. Since 2001, adults have had higher hepatitis A rates than children. Currently, the highest rates are among men between 25 and 39 years of age.

In a related editorial, Dr. Pierre Van Damme and Dr. Koen Van Herck, from the University of Antwerp in Belgium, comment that factors other than vaccination, such as improved environmental and hygienic conditions, could have contributed to the drop in hepatitis A rates. "Only continued disease surveillance will allow confirmation of the real impact" of the vaccine program.

JAMA 2005;294:194-201,246-248.