Decades of vaccination and prevention efforts may have the hepatitis viruses on the run, according to a new report from the U.S. Centers for Disease Control and Prevention.

The CDC researchers tracked individuals’ levels of antibodies to various hepatitis strains. Antibodies are a kind of immune system record of exposure to a particular pathogen, either through infection or vaccination.

Since the late 1980s, there’s been a significant increase in the number of U.S.-born American children and teens with hepatitis A antibody and a decrease in the number of adults aged 40 and older with the antibody, the study found.

The recent trends likely result from increased immunity in children due to immunization and a resulting decrease of hepatitis A virus (HAV) exposure and infection among adults, according to the CDC researchers.

The investigators also found that hepatitis B virus (HBV) infection among people aged 6 to 39 significantly decreased in recent years as a result of vaccination programs. By 2003-2006, more than 90 percent of U.S. children had received at least one dose of hepatitis B vaccine, according to a news release from the CDC.

The rate of hepatitis C virus (HCV) infection is decreasing among people at highest risk of infection, possibly due to prevention programs that target risky behavior such as injection drug use, the researchers noted. The peak age of HCV infection changed from 30 to 39 years during 1988-1994 to 40 to 49 years during 1999-2008.

Viral hepatitis is a major public health concern in the United States and HAV, HBV and HCV are the three most important types of hepatitis. HBV and HCV can cause chronic infection that’s associated with chronic liver disease and liver cancer. HCV is the most common chronic blood-borne infection in the U.S. because 70 percent to 85 percent of people acutely infected become chronically infected.

(Source: HealthDay News)