Even if measles is eradicated, immunisation may still be desirable in developing countries

Measles still kills 800 000 children in developing countries every year,1 although immunisation has substantially reduced the number of deaths. Immunisation lowers mortality primarily by reducing the incidence of measles, but it may also lower mortality by increasing the age at which children are infected and by reducing the severity of infection in immunised children and their contacts.2 Morever, the vaccine itself may reduce mortality from conditions other than measles.

Epidemiological research has shown two important characteristics of measles: the severity of clinical illness is largely determined by the infecting dose, and, surprisingly, mild infection and standard doses of Schwarz vaccine substantially reduce mortality from conditions other than measles.3 Children infected with a large dose of measles virus have a shorter incubation period, more severe disease, and a higher mortality. Children who are infected outside the home (primary cases) have milder disease than secondary cases (who are …