Measles is a highly contagious viral disease. Symptoms appear between eight and 13 days after exposure to the virus and include a runny nose, cough, eye infection, rash and high fever. There is no specific treatment for measles – patients are isolated and treated with vitamin A, and for any complications: these can include eye-related problems, stomatitis (a viral mouth infection), dehydration, protein deficiencies and respiratory tract infections.

In high-income countries, most people infected with measles recover within two to three weeks, and mortality rates are low. In developing countries, however, the mortality rate can be between 3 and 15 per cent, rising to 20 per cent where people are more vulnerable. Death is usually due to complications such as severe respiratory infection, diarrhoea, dehydration or encephalitis (inflammation of the brain).

A safe and cost-effective vaccine against measles exists, and large-scale vaccination campaigns have significantly decreased the number of cases and deaths. However, large numbers of people are left susceptible to the disease, especially in countries with weak health systems, where outbreaks are frequent and where there is limited access to health services.

MSF treated 45,900 patients for measles and vaccinated 1,537,400 people in response to outbreaks in 2015.