SEX DIFFERENCES IN SUSCEPTIBILITY TO INFECTIONS

Abstract

Sex differences in vulnerability to infectious diseases have been defined by a search of the world's literature and a study of the Johns Hopkins Hospital case records covering the period from 1930 to 1963. Special attention has been focused on bacterial meningitis at all ages and bacterial septicemia in children less than 15 years of age. A significant male preponderance is seen in all the data, but it is most marked in infancy. This is also the period in which infections by Gram-negative enteric bacilli outnumber those by Gram-positive organisms and this difference affects males more than females. The advent of antibiotics and related therapy has been associated with an increased sex ratio in incidence of infectious diseases, even as death rates from these diseases decreased. The sex differences in susceptibility to the infections cited in this paper are consistent with the expectations of a genetic hypothesis that concerns a gene locus on the X chromosome of human beings, which is involved with synthesis of immunoglobulins. In general one might expect greater resistance to infectious diseases in that sex for which heterozygosity is possible. More direct evidence for the hypothesis must come from comparative studies of the immune mechanism in the two sexes.