Polio (Poliomyelitis)

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Polio is an infectious disease caused by a virus. The virus reproduces itself in the gut and can spread easily to the nervous system. It can result in very serious consequences including meningitis, paralysis or death.

Before a vaccine was introduced in the 1950s, epidemics would result in up to 7760 cases of paralytic polio in the UK each year, with up to 750 deaths. Once a vaccine was routinely available, cases of polio rapidly fell to very low levels. The last outbreak of polio in the UK was in the late 1970s, and the last case of naturally-occurring polio in the UK was in 1984.

Vaccination has eliminated polio in almost all countries in the world. Only three countries still officially have polio circulating in the population: Afghanistan, Pakistan and Nigeria. However, Syria, which was polio-free for 14 years, was re-infected with the virus from Pakistan. Polio cases there have increased as a result of the civil war, which has had a major impact on sanitation and on routine vaccination. Other countries have had a few polio cases in recent years, often linked to war or civil unrest.

Europe has been certified as 'polio free' since 2002, and the risk of importing polio into the UK is considered to be low at the moment. However there have been at least two outbreaks of polio in Europe since 2002, both linked to cases imported from other parts of the world. In 2018 the World Health Organization's view is that three European countries (Bosnia and Herzegovina, Romania and Ukraine) are of special concern because of lower vaccination rates and other issues.


The majority of people infected with polio show no symptoms. However they are still infectious, so it possible to carry and pass on the disease without realising.

Common symptoms of polio are:

  • fever
  • headache
  • upset stomach
  • stiffness of the neck and back
  • paralysis

Polio can also lead to meningitis. (See the Meningitis Research Foundation website for more detailed information on the signs and symptoms of meningitis.)


Polio is caused by infection with one of three types of virus. The virus is passed on from person to person through contact with faeces (poo), saliva or mucus.


The recommended way to get protection against polio is vaccination. Babies in the UK are protected by the 5-in-1 vaccine (for babies born or or before 31st July 2017) or the 6-in-1 vaccine (for babies born on or after 1st August 2017). Follow-up doses are given in the Pre-school Booster and the Teenage Booster vaccines.


Until 2004, the vaccine used in the UK was a live attenuated (weakened) oral polio vaccine (OPV). In a small number of cases this vaccine actually caused polio itself (30 cases in UK between 1985 and 2002). Although the disease had been eradicated in the UK, it remained endemic in many countries, so there was a risk it could be reintroduced to the UK through travel and immigration.

By 2004, vaccination had eradicated polio from all but a few countries worldwide, and the UK was able to switch over to the inactivated (killed) polio vaccine, which does not contain any live viruses and cannot cause the disease itself.


Page last updated Monday, August 13, 2018