GIARDINI NAXOS, SICILY, ITALY -- April 11, 2003 -- Doctors reported Friday that no data exists indicating that booster vaccinations of hepatitis A vaccine are necessary.
 

"Effective vaccines against hepatitis A have been available since 1992, and they provide long-term immunity against the infection," said Pierre Van Damme, MD, University of Antwerp, Belgium. "There is no worldwide consensus on low long protection will last or whether there will be a need for hepatitis A booster vaccinations in the future."
 

In a post presentation at the 21st Annual Meeting of the European Society for Paediatric Infections Disease, Dr. Van Damme and colleagues reviewed data from various studies. A panel of experts was convened in June 2002 to review the available data.
 

"The group concluded that there is no evidence to support hepatitis A booster vaccination following successful primary vaccination in a healthy individual, although further investigations are required before deciding if boosters may be omitted in special patient groups," Dr. Van Damme reported.
 

He cited several studies which support the groups conclusion, including indirect evidence of hepatitis A immune memory in a study of 31 adults who, 12 years after inoculation with hepatitis A vaccine, were challenged with an half dose of an adult hepatitis A vaccine and had a corresponding rapid increase in antibody levels.
 

He also cited studies of adult travelers, which showed that a delay in timing of a second dose -- as much as 6 years after the first dose -- does not appear to affect the immune response. Several animal and humans studies also demonstrated long-term cell-mediated responses.
 

Dr. Van Damme said the consensus statement from the panel is expected this year in the medical journal The Lancet.
 

While there is no evidence that immunocompetent individuals who have received a full vaccination course require a booster dose, Dr. Van Damme, said, "long-term studies are recommended in special patients groups -- including immunocompromised patients -- to evaluate antibody persistence and vaccine efficacy."