Download PDF Measles infection and encephalitis

by Dr Natasha Crowcroft, Consultant Medical Epidemiologist and reviewed by Dr Sylviane Defres, Institute of Infection and Global Health, University of Liverpool

Measles infection and encephalitis

Measles causes encephalitis in children with measles infection. This can happen as a result of the brain becoming infected with the virus during the rash phase of the illness or by an immune-mediated brain inflammation subsequent to measles infection. Measles is also the cause of a disease called subacute sclerosing panencephalitis (SSPE). This is a rare condition that can develop some years after natural measles infection. SSPE is a degenerative neurological condition which progressively destroys nerve cells in the brain almost always leading to mental deterioration and death.  More information on SSPE is available on our SSPE factsheet.

MMR vaccine

Measles, mumps and rubella (MMR) vaccine is a very effective way to prevent against these diseases. All three of these infections are important causes of encephalitis, and before MMR vaccine was introduced all three infections were common in the UK. 

The vaccine is unequivocally safer than letting children catch the diseases. In a study carried out in Finland between 1982 and 1986 of over half of  million children, it was found that the incidence of encephalitis in the three months following a MMR vaccination was no different to the overall incidence. The example below compares the risk of measles with the risk of MMR vaccine.

Measles

  • 1-3 in 1,000 children contracting measles will develop encephalitis concurrent with the measles infection.                10–15% of those children will die and a further 25% will be left with permanent neurological damage.
  • 1 in 1,000 children with measles will develop post-infectious encephalitis.
  • 1 in 25,000 of children (1 in 5,500 children if they are under 1) with measles will develop subacute sclerosing panencephalitis (SSPE) which has a fatal (death) outcome.
  • 1-2 in 1.000.000 children who had vaccination will develop encephalitis from the vaccination which is less than the incidence of all types of encephalitis.

In the past decade, coverage of measles, mumps and rubella vaccination in the UK has not been high enough. Many countries across Europe are currently experiencing large epidemics of measles because not enough children have had the MMR vaccine. In 2013, outbreaks of measles were reported in the North-West of England (376 cases) and Swansea (664 cases). Acute encephalitis contributed to two of three measles related deaths reported in Europe in 2012. This highlights how important it is to make sure that children are protected from this preventable disease.

Measles encephalitis caused the death of Roald Dahl’s daughter Olivia in 1962. He became an ardent supporter of measles vaccination as a result of the tragic loss of his daughter. He wrote a letter (please see below) to parents encouraging them to get their children vaccinated.

Letter to parents


FS043V3 Measles infection and encephalitis

Date created: May 2006; Last updated: February 2017; Review date: February 2020

Disclaimer: We try to ensure that the information is easy to understand, accurate and up-to-date as possible.                 

If you would like more information on the source material the author used to write this document please contact the Encephalitis Society. None of the authors of the above document has declared any conflict of interest which may arise from being named as an author of this document.