Nosocomial hepatitis A. A multinursery outbreak in Wisconsin.

Seven premature infants contracted asymptomatic hepatitis A while hospitalized in an intensive care nursery (nursery A) from May through August 1981. Fifteen secondary cases occurred between Aug 13 and Oct 14 and included six family members of nursery A infants, five nursery A nurses, and three nurses and a physician at two other nurseries--B and C. Nurseries B and C had each received an infected infant transferred from nursery A in July. An epidemiologic investigation was conducted to determine the mode of transmission of hepatitis A in infants. A common vehicle was not identified. Review of dates of onset of illness in adults suggested that hepatitis A was transmitted in at least two generations of illness in infants at nursery A. Evaluation of infant handling in nursery A, using a case-control study, suggested that hepatitis A was transmitted among infants by nurses. Asymptomatic infected premature infants can be a source of hepatitis A in nursery infants and personnel and in the community.