Measles - Fact sheet

What is measles?

• Measles is an acute infection caused by the measles virus.

Who catches measles?

• 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.

How do you catch measles?

• Measles is caught through direct contact with an infected person, or through the air when he or she coughs or sneezes.

How infectious is measles?

• About 90% of people who have not been immunised or had a past infection develop measles if they live in the same house as someone with measles.
• Measles is most infectious before the rash appears and only trivial contact may be sufficient for the virus to spread.

What is measles like?

• Symptoms develop 9-11 days after becoming infected and last up to 14 days from the first signs to the end of the rash.
• The first stage of measles includes irritability, a runny nose, conjunctivitis (red eyes), a hacking cough and an increasing fever that comes and goes. These symptoms may last up to 8 days.
• The rash starts from day 4 and the fever peaks at around 40.6oC (105oF). The rash usually starts on the forehead and spreads downwards over the face, neck and body.
• The rash consists of flat red or brown blotches which can flow into each other. It lasts 4-7 days.
• There can also be diarrhoea, vomiting and abdominal pain.

How serious is measles?

• One million children die from measles world-wide each year. In developing countries with poor vaccination programmes measles is a more severe disease. In the UK measles is rare. There were 4168 notified cases in 1997, but as few are confirmed many were probably rashes due to other viruses when the measles diagnosis was wrong.
• Even in the UK, complications are quite common. They include a severe cough and breathing difficulties (croup), ear infections, viral and bacterial lung infections (pneumonia), and eye infections (conjunctivitis). Most are caused by secondary bacterial infections which can be treated with antibiotics.
• The most serious problems involve the nervous system. Inflammation of the brain (acute encephalitis) occurs 2-6 days after the rash has appeared. Less than 1 in 1000 measles cases is affected in this way, but 25% of those are left with brain damage.
• SSPE (subacute sclerosing pan-encephalomyelitis) is the most severe complication of measles. It usually occurs years after the initial illness and is a slowly progressive brain infection. SSPE starts with intellectual impairment and deteriorates to seizures and eventually death. It is, however, very rare occuring in less than 1 in 100000 cases of measles.
• Measles infection during pregnancy can result in the loss or early birth of the baby.
  Severe disease and complications are most likely in infants under 12 months, those with weakened immune systems, the malnourished and children with vitamin A deficiency.

Can you prevent measles:

• Measles can be prevented by a highly effective vaccine. This is part of the measles-mumps-rubella (MMR) immunisation with a first dose at 12-15 months and a second dose at 4-5 years.
• Pregnant women or those with weakened immune systems should not be immunised.
• Past infection gives immunity.
• Immunisation programmes are essential prevent measles cases in the UK. The World Health Organisation (WHO) has set a goal of the global eradication of measles by 2005-2010. This needs over 95% of all people to be immunised.

How soon should a child be back at school after measles?

• Measles is most infectious from 4 days before the appearance of the rash until 4 days afterwards. The DFEE and DoH guidelines on infection control in schools and nurseries recommend that a child should be kept off school for 5 days after the onset of the rash.
• Measles is a notifiable disease and must be reported by a doctor to the local health authority. A saliva test to confirm or refute the diagnosis may be suggested.

How can you treat someone with measles?

• There is no specific treatment for measles. The patient should drink lots of clear fluid to replace body water lost through the fever.
• Paracetamol can be used to reduce the fever. Aspirin should NOT be given to children as its use is associated with Reye's Syndrome (a severe neurological disorder).
• Children with measles should be closely monitored for complications and the doctor consulted on what symptoms to look for.