The national measles and rubella campaign that begins next month is one of the most ambitious vaccination initiatives that Britain has undertaken. The aim is to vaccinate 95% of the seven million schoolchildren aged between 5 and 16 within one month and so to prevent an epidemic of measles that would otherwise be likely to occur early next year.1,2 The novel feature of this campaign is that it is meant to prevent an epidemic: the more usual response is to wait for an outbreak to occur before doing anything. This preventive action is likely to be far more cost effective than attempts to curtail spread once the chains of transmission are established. Experience in North America has shown that, despite the adoption of prompt and aggressive measures to control outbreaks, transmission is rarely interrupted.3,4

The campaign is based on comprehensive epidemiological surveillance data including serological studies, number of cases notified and confirmed, rates of complications …