Effect of immunoglobulin on hepatitis A in day-care centers.

Over a 21-month interval, we investigated the effectiveness of immunoglobulin (lg) in preventing hepatitis A spread in day-care centers. Immunoglobulin was given to all center and employees whenever hepatitis occurred in one center child or employee or parents in two families. Immunoglobulin programs were completed in 91 centers during the trial within an average of 17 days of onset of illness in the index case. Immunoglobulin intervention caused significant reduction in the average size of a day-care hepatitis outbreaks, from 7.3 cases in historically untreated centers to 6.0 cases in Ig-treated centers. Cases in center children and employees virtually ceased two weeks after Ig intervention, while those in household contacts decreased significantly within six weeks. Reported cases of hepatitis type A or unspecified in the community decreased 75%, and the number of new hepatitis outbreaks decreased 77% during the trial. A decrease occurred not only in day-care-associated cases, but in cases not directly associated with centers, probably due to decreased tertiary spread from day-care families into the community. Use of Ig to prevent hepatitis spread in day-care centers seems to be an excellent means of controlling this disease, both within the centers and the general community.