Polio

Polio is a serious viral infection. It used to be common in the UK and across the world, but it's rare nowadays because vaccination can prevent it.

Most people with polio don't have any symptoms and won't know they're infected. But in up to 1 in 100 people, the polio virus causes temporary or permanent paralysis, and this can be life threatening.

Cases in the UK fell dramatically once routine vaccination was introduced in the mid-1950s. No one has caught polio in the UK since the mid-90s. The infection is still found in some parts of the world, though, and there's a very small risk it could be brought back to the UK.

There's no cure for polio. So make sure you and your children are fully vaccinated against it.

About 95% of people with polio won't have any symptoms. Their bodies fight off the infection and they never realise they were infected.

A small number of people get a flu-like illness 3 to 21 days after they're infected. The symptoms can include:

• a high temperature (fever) of 38C (100.4F) or above
• a sore throat
• a headache
• abdominal (tummy) pain
• aching muscles
• feeling and being sick

These symptoms usually pass within about a week.

In less than 1% of cases, the polio virus attacks the nerves in the spine and at the base of the brain. This can cause paralysis, usually in the legs, which develops over hours or days.

The paralysis isn't usually permanent, and movement often returns slowly over the next few weeks and months. But some people are left with lasting problems. If the breathing muscles are affected, polio can be life threatening.

Polio often passes quickly without causing any other problems, but sometimes it leaves difficulties that last, even for life.

About 1 in every 200 people with the infection will have some degree of permanent paralysis. Others may be left with problems that need long-term treatment and support. These can include:

• muscle weakness
• shrinking of the muscles (atrophy)
• tight joints (contractures)
• deformities, such as twisted feet or legs

There's also a chance that someone who's had polio in the past will develop similar symptoms again, or find their existing symptoms getting worse, many decades later. This is known as post-polio syndrome.

You can catch polio if you come into contact with the poo (faeces) of someone who has the infection. You can also catch it from the droplets that get launched into the air when they cough or sneeze. Food or water contaminated with infected poo or droplets can pass it on too.

If the virus gets into your mouth, it travels to your throat and bowels, where it starts to multiply. In some cases, it also gets into the bloodstream and spreads to the nervous system.

A person with the infection can spread the virus from about a week before any symptoms develop, and for several weeks afterwards. People who have no symptoms at all can still pass polio on to others.

There have been rare cases where polio was caused by a vaccine containing a live version of the polio virus. This is no longer a risk in the UK, because the vaccine used there nowadays contains an inactive version of the virus.

Thanks to routine vaccination programmes, polio has been largely wiped out in most parts of the world. The World Health Organization (WHO) has declared Europe, the Americas, the western Pacific region and, most recently, southeast Asia polio-free.

But polio is still found in some places. It remains a significant problem in Afghanistan, Nigeria and Pakistan, and there's a potential risk of infection in other parts of Africa and some Middle Eastern countries.

If you're planning to travel, you can use the Travel Health Pro website to check whether there's a risk of getting polio in the country you plan to visit. The website's country guide has further information.

There's no cure for polio at the moment. Treatment focuses on supporting the body's functions and lowering the risk of long-term problems while the body fights off the infection.

This can include bed rest in hospital, painkillers, breathing support, and regular stretches or exercises to prevent problems with the muscles and joints.

If polio leaves you with long-term problems, you'll probably need ongoing treatment and support. This may include physiotherapy to help with any movement problems, and devices such as splints and braces to support weak limbs or joints. Occupational therapy can help you adapt to any difficulties, and surgery may sometimes be needed to correct any deformities.

The polio vaccine is given in 5 separate doses:

• at 8, 12 and 16 weeks of age, as part of the 6-in-1 (DTaP/IPV/Hib/HepB) vaccine
• at 3 years and 4 months of age, as part of the 4-in-1 (DTaP/IPV) pre-school booster
• between 13 and 18 years of age, as part of the 3-in-1 (Td/IPV) teenage booster

If you're planning to travel to a country affected by polio, you should get immunised if you haven't been fully immunised before. If you have been, you should have a booster dose if it's been 10 years or more since your last dose of the vaccine.

You can get immunised against polio at any time if you haven't been fully immunised before. You don't need to be travelling to a place where there's a risk of infection.

If you've had polio in the past and never been immunised, it's still recommended that you get fully immunised. The vaccine protects against 3 types of polio virus, and people who have had the infection before are immune to only one of them.

Cases of polio rose around the world in early 2014, and the WHO responded by issuing temporary extra travel recommendations for people visiting countries where polio is found. Depending on where you plan to go, what you'll be doing there and how long you'll stay, you may now be advised to have a booster polio immunisation before you travel, if you haven't had one in the past 12 months.

Some of the countries where there's a risk of infection ask for proof of immunisation before they let you travel on elsewhere. If you don't have this proof, you may be given a booster dose before you leave.