Objective: To examine whether contracting measles from a sibling of the opposite sex affects mortality.
Design: Prospective registration during 15-20 years of all births and deaths, including 243 measles related deaths. Measles infection was not registered; however, as in fatal cases measles was probably contracted from a maternal sibling the risk of dying during measles outbreaks was examined in families with two boys, two girls, or a boy and a girl.
Setting: 31 small villages in two rural areas of eastern Senegal.
Subjects: 766 children living in families with two children aged under 10 years during outbreaks of measles, 107 (14%) of whom died of measles.
Main outcome measure: Deaths from measles, size of village, age and sex of maternal siblings.
Results: The interval between outbreaks in the same village was greater than 10 years. The risk of dying of measles was significantly related to age, increasing with the age difference between siblings and decreasing with the size of village. In a multiple logistic regression analysis adjusting for these background factors, children in families with a boy and a girl had a significantly higher mortality than children in families with two boys or two girls (odds ratio = 1.81, 95% confidence interval 1.17 to 2.82). The increase in risk was the same for boys and girls in families with two children one of whom was a boy and one a girl.
Conclusion: Cross sexual transmission may be an important determinant of severity of measles infection.
PIP: The effect of contracting measles from a sibling of the opposite sex on mortality was examined. 31 small villages in 2 rural areas of eastern senegal were the sites for this prospective registration during a 15-20 year period covering all births and deaths, including 243 measles-related deaths. Measles infection was not registered; however, as in fatal cases, measles was probably contracted from a maternal sibling. The risk of dying during measles outbreaks was examined in families with 2 boys, 2 girls, or a boy and a girl. A total of 766 children living in families with 2 children under age 10 during these measles outbreaks were included in this study, 107 (14%) of whom died of the disease. The main outcome measures evaluated were: deaths from measles, the size of the village, and the age and sex of maternal siblings. The interval between outbreaks in the same village was greater than 10 years. The risk of dying from measles was significantly related to age, increasing with the age difference between siblings and decreasing with the size of the village. In a multiple logistic regression analysis adjusting for these background factors, children in families with a boy and a girl had a significantly higher mortality than children in those families with 2 boys or 2 girls (odds ratio=1.81, 95% confidence interval, 1.17-2.82). The increase in risk was the same for boys and girls in families with 2 children, 1 of whom was a boy and 1 a girl. It seems, therefore, that cross-sexual transmission may be an important determinant of severity of measles infection.