Measles is an acute infection caused by the measles virus. Measles is now rare in the UK because of the high levels of immunisation. Measles is usually a childhood infection and is most common in the 1-4 year old age group in children who have not been immunised. However, you can catch measles at any age.
Epidemics often coincide with school terms when there is much more close contact between children.
Measles is caught through direct contact with an infected person, or through the air when he or she coughs or sneezes. Measles is most infectious before the rash appears and only trivial contact may be sufficient for the virus to spread. Symptoms develop 9-11 days after becoming infected and last up to 14 days from the first signs to the end of the rash. These symptoms may last up to 8 days. The rash usually starts on the forehead and spreads downwards over the face, neck and body.