Studies on the agent of infectious hepatitis. III. The effect of skin tests for infectious hepatitis on the incidence of the disease in a closed institution.

At the onset of an epidemic in a closed institution about one-fourth of the inmates were skin-tested. During the year following the skin test, 5 cases of hepatitis with jaundice were recorded among 320 skin-tested individuals with unknown histories, one in the 144 skin test-positive, and 4 in the 176 skin test-negative subjects. In contrast 112 cases occurred among the 825 non-skin-tested individuals. Thus, the incidence of jaundice in the skin-tested group was 1.6 per cent as against 13.6 per cent in the non-skin-tested individuals. Possible explanations for this observation have been discussed.