Public Health

Study supports hepatitis A vaccination in the second year of life

Last Updated: 2007-02-21 15:41:13 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Passively transferred maternal hepatitis A virus (HAV) antibody persists in most infants born to anti-HAV-positive mothers for at least 6 months after birth and appears to interfere with the immune response to hepatitis A immunization.

"This interference is manifested primarily by lower antibody concentrations rather than failure to respond to vaccination," Dr. Beth P. Bell from the Centers for Disease Control and Prevention, Atlanta, and colleagues in Anchorage, Alaska, report in The Pediatric Infectious Disease Journal for February.

Their findings are based on a comparison of the immunogenicity of an inactivated hepatitis A vaccine in 108 infants born to immune mothers and 140 born to susceptible mothers.

"By 12 months of age, only a minority of infants had detectable passively transferred maternal antibody and the concentrations were lower than those measured at age 6 months," the team reports.

Among infants who were vaccinated beginning at either 12 or 15 months of age, there were no marked differences in the immune response to vaccination between those born to anti-HAV-positive and anti-HAV-negative mothers.

Routine hepatitis A vaccination of young children can generate "enormous public health benefits," as shown by plummeting rates of acute hepatitis A in areas where the practice has been implemented, Dr. Bell and colleagues note in their report.

They point out that until recently, hepatitis A vaccines were licensed in the U.S. only for children at least 2 years of age, but now the U.S. Food and Drug Administration has approved their use beginning at 12 months of age. "The findings of the current study provide strong scientific support for vaccination in the second year of life," the investigators conclude.

Pediatr Infect Dis J 2007;26:116-122.