Hepatitis A is a liver-infecting virus spread through contaminated food and water. It is rarely fatal and most often causes jaundice, a yellowing of the skin due to reduced liver function, and flu-like symptoms that can persist for weeks.

In Israel, the annual incidence of hepatitis A dropped from about 41 cases per 100,000 people in 1995 to less than 5 cases per 100,000 in the first quarter of 2002. The findings were presented by Professor Ron Dagan of the Pediatric Infectious Disease Unit at Soroka University Medical Center and Ben-Gurion University of the Negev, Beer-Sheva.

National vaccination against hepatitis A was first introduced in Israel in July of 1999, when a vaccine was incorporated into the routine childhood immunization program.

The vaccine was offered free of charge and given in two doses to children at 18 months and 2 years of age. It was not offered to other age groups, since it was thought that aiming at toddlers--who are most likely to spread the disease--would result in protection of other individuals.

"The vaccine coverage was approximately 90% of toddlers, and only a small fraction of people that were outside the target population were sporadically vaccinated," Dagan told Reuters Health.

He remarked that the immunization program decreased the burden of disease not only among vaccine recipients but also among older groups, even though most of them did not receive the vaccine.

"The abrupt reduction of the disease in all groups is explained by the high level of immunity achieved in toddlers, who are the major transmitters of hepatitis A virus into the general population. These results challenge the need for a catch-up program," Dagan concluded.

Most hepatitis A infections occur in children under 10, who may not have any symptoms, or flu-like symptoms that can be mistaken for other illnesses. The infection can be more serious in adults, although it does not cause a chronic, lingering infection like other forms of hepatitis, such as hepatitis B and hepatitis C.

The US Centers for Disease Control and Prevention (news - web sites) notes that improved sanitation and personal hygiene, such as washing the hands after using the toilet or changing a diaper, can help prevent transmission of the virus. A vaccine is available in the US to people aged 2 and older, and the federal agency suggests that children who live in communities with higher-than-average hepatitis A rates be routinely vaccinated. Most such communities are in the Western US.