Hepatitis B virus infection among children born in the United States to Southeast Asian refugees.

Since 1975 nearly 1 million persons have entered the United States from Southeast Asia, where infection with hepatitis B virus (HBV) is hyperendemic. To evaluate the prevalence and patterns of transmission of HBV infection among the children of refugees from Southeast Asia, we studied 196 refugee families with 257 children born in the United States. Of 31 children born in the United States to mothers with infectious disease, 17 (55 percent) had been infected with HBV. Of 226 children whose mothers did not have infectious disease, 15 had HBV infection--a prevalence of 6.6 percent (95 percent confidence interval, 4.1 to 10.7). The risk of infection was greatest (26 percent) among children living in households with children with infectious disease (relative risk, 5.5; confidence interval, 2.3 to 13.4). Exposure to fathers or other adults with infectious disease was not significantly associated with infection. Of children from households with no persons with infectious disease, 3.9 percent (confidence interval, 1.7 to 8.8) were infected. Nearly half (46 percent) the cases of HBV infection among the U.S.-born children of refugees were not attributable to perinatal transmission from a mother with infectious disease. We conclude that child-to-child transmission may be occurring within and between households. Current recommendations to immunize the newborns of mothers with infectious disease are not sufficient to protect all U.S.-born children of Southeast Asian refugees from HBV infection early in life, when the risk of chronic sequelae and premature death is highest. We recommend that the HBV vaccination policy be expanded to include all newborns of Southeast Asian immigrants.