Serverity of Measles and Cross-Sex Transmission of Infection in Copenhagen 1915–1925

Abstract

Using data on children hospitalized with measles in Copenhagen in 1915–1925, it was found that secondary cases infected at home by someone of the opposite sex had a relative case-fatality rate risk (RR) of 1.52 (95% confidence interval (Cl): 0.80–2.88) compared with secondary cases infected by someone of the same sex. Males infected by a girl suffered more severely than when infected by another boy (RR = 2.46; 95% Cl: 1.00–6.04) whereas there was no difference for girls. In households with two case of measles, case fetality was significantly higher in families with a boy and a girl infected at the same time compared with families with two boys or two girls (RR = 1.89; 95% Cl: 1.06–3.37). There was no difference in mortality in families with two boys or two girls having measles at the same time. These results strengthen previous observations from Guinea-Bissau that close contact with a child of the opposite sex increases the severity of measles infection.