Measles is an acute, highly contagious viral illness causing a high fever and a rash. It is spread by airborne or droplet transmission i.e. coughing and sneezing.
The incubation period is about 10 days and the illness starts with a fever, head cold-like symptoms, conjunctivitis (red, sore, swollen eyes) and a cough. After about two to four days the rash appears. The rash starts at the head spreading to the body, arms and legs over the next three to four days.
Measles is most infectious from when the first symptoms appear to four days after the appearance of the rash.
The most common complications of measles infection are otitis media (7-9% of cases), pneumonia (1-6%), diarrhoea (8%) and convulsions (one in 200). Other more rare complications include encephalitis (overall rate of one per 1000 cases of measles) and sub-acute sclerosing pan-encephalitis (SSPE). Overall complications of measles are more common and more severe in poorly nourished and chronically ill children, including those who are immunosuppressed.
Measles is a major health problem, especially in the developing world. The introduction of two doses of measles containing vaccine into the national immunisation schedule has brought measles largely under control in the UK although there has been a rise in cases in recent years. A surge in the number of cases was reported in the first half of 2011 with more cases being reported in the first five months of that year than in the whole of 2010. It is thought that the rise in the number of cases of measles is due to parents not getting their children vaccinated with the MMR vaccine. At the beginning of 2012 localised outbreaks of disease were reported in North Wales and the North West of England. Many of the cases either occurred in unvaccinated children below the age of 10 or in older children who transmitted the virus to younger, unvaccinated siblings.
Measles is a serious disease which can be prevented by vaccination. In the UK vaccination against measles infection is included in the childhood vaccination schedule. The vaccine is part of the measles, mumps and rubella (MMR) combined vaccine. The first dose is given between twelve to thirteen months of age and the second at 3 years and 4 months or soon thereafter.