tification of 20 other cases of acute hepatitis A among persons who had close personal contact with newly arriving internationally adopted children and no history of traveling abroad (8). Two acute hepatitis A cases were identified among traveling parents who had not been vaccinated. This same study found that 98% of parents traveling to pick up their children had been vaccinated against hepatitis A in accordance with existing ACIP recommendations (8).
Since 2007, CDC has received 14 additional reports of acute hepatitis A following exposure to nonjaundiced adoptees newly arriving from countries of high or intermediate hepatitis A endemicity. Although these numbers are small compared with the total number of hepatitis A cases (2,979) reported to CDC in 2007 (9), they likely represent an underestimate of the number of hepatitis A cases associated with international adoptions because contact with an international adoptee is not asked routinely as part of national hepatitis A surveillance. All of the 14 adoptee-associated cases identified since 2007 were in close contacts who had not been vaccinated against hepatitis A and had no history of travel and no other risk factors for hepatitis A. In one instance, both adoptive parents developed hepatitis A that required hospitalization (CDC, unpublished data, 2008). In another instance, a 2008 community outbreak with 12 hepatitis A cases was associated with an asymptomatic HAV-infected international adoptee; two infected contacts were hospitalized, and disease was identified among tertiary contacts in an elementary school (CDC, unpublished data, 2009).
Data from a study conducted at three adoption clinics in the United States, each screening 100--200 incoming adoptees for hepatitis A each year, indicate that 1%--6% of newly arrived international adoptees are acutely infected with HAV (non-jaundiced; IgM anti-HAV positive). A proportion of these adoptees represent a source of infection for susceptible close contacts (9). The risk for hepatitis A among close personal contacts of international adoptees is estimated at 106 (range: 90--819) per 100,000 household contacts of international adoptees within the first 60 days of their arrival in the United States (CDC, unpublished data, 2009). By comparison, according to surveillance data, the estimated rate of symptomatic hepatitis A in the U.S. general population in 2007 was 1.0 per 100,000 population (10).
Based on this evidence, on February 25, ACIP updated its guidance by recommending hepatitis A vaccination for all previously unvaccinated persons who anticipate close personal contact (e.g., household contact or regular babysitting) with an international adoptee from a country of high or intermediate endemicity during the first 60 days following arrival of the adoptee in the United States. The first dose of the 2-dose hepatitis A vaccine series should be administered as soon as adoption is planned, ideally 2 or more weeks before the arrival of the adoptee.
- CDC. Update: prevention of hepatitis A after exposure to hepatitis A virus and in international travelers: updated recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2007;56:1080--4.
- CDC. Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2006;55(No. RR-7).
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- Armstrong GL and Bell BP. Hepatitis A virus infections in the United States: model-based estimates and implications for childhood immunization. Pediatrics 2002;109:839--45.
- Glikson M, Galun E, Oren R, Tur-Kaspa R, Shouval D. Relapsing hepatitis A: review of 14 cases and literature survey. Medicine 1992;71:14--23.
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