Epidemiology

High prevalence of hepatitis A virus in internationally adopted children

Last Updated: 2010-10-11 18:55:50 -0400 (Reuters Health)

By Frederik Joelving

NEW YORK (Reuters Health) - Screening children adopted from abroad may be a good idea, according to a U.S. study that found a high prevalence of hepatitis A in such children.

"Many children will already be protected against hepatitis A through past infection, so serologic testing can help with immunization decisions so children who are protected can avoid immunizations that are not needed," said Dr. Mary Allen Staat, who directs the International Adoption Center at Cincinnati Children's Hospital Medical Center in Ohio.

"If the IgM is positive, then family members and close contacts should receive hepatitis A vaccine to prevent infection," she told Reuters Health by e-mail.

Last year the Advisory Committee on Immunization Practices (ACIP) took a broader stance: it recommended hepatitis A vaccination for close personal contacts of children who have been adopted from countries with high or intermediate rates of the disease. The ACIP advised that the first dose be administered when the adoption is planned, ideally at least 2 weeks before contact with the adoptee. (See Reuters Health story of Sep 17, 2009.)

Dr. Staat and colleagues, whose findings appeared online today in Pediatrics, reviewed results for 288 children who had undergone hepatitis A virus serologic testing within four months of arrival in the U.S. More than half were screened within two weeks.

Of 279 kids with total antibody results, 29% had positive findings. Region and increasing age were independently associated with immunity on multivariate analysis.

Overall, 72% of children from Africa had immunity, compared to 39% of those from Latin America and the Caribbean, 22% of Eastern Europeans and 17% of those from Asia and the Pacific Rim.

Three of 270 children (1%) had IgM antibodies to hepatitis A virus.

The CDC requires clinical symptoms to be present in addition to IgM antibodies for infections to be considered acute. In the U.S., CDC data show the incidence of acute infections was 1 per 100,000 in 2007. (By contrast, the ACIP estimates the risk for hepatitis A to be 106 per 100,000 household contacts of international adoptees within 60 days of their arrival in the US.)

Although all three children described in the new study were asymptomatic, the adoptive father of one 27-month-old Russian girl developed fever and jaundice shortly after adopting her. Serologic testing was positive for both total and IgM hepatitis A virus-specific antibodies.

"We wanted to share our experience with one of the children who had acute hepatitis A infection to highlight the asymptomatic nature of acute hepatitis A infection in young children and the need to reconsider the current case definition," said Dr. Staat.

According to the researchers, the American Academy of Pediatrics says screening for acute hepatitis A virus should be considered for children who spent their childhood in endemic areas.

SOURCE: http://link.reuters.com/dus87p

Pediatrics 2010.