Polio: what it is, symptoms, how it spreads and vaccination

Polio (poliomyelitis) is a viral infection. NHS inform describes it as a serious viral infection that used to be common in the UK and worldwide and is rare nowadays because it can be prevented with vaccination. UKHSA, in its Green Book chapter for health professionals, says poliomyelitis follows invasion through the gastrointestinal tract by one of three serotypes of polio virus (1, 2 and 3), with the virus replicating in the gut and having a high affinity for nervous tissue.

In a small number of people the virus gets into the bloodstream and spreads to the nervous system. NHS inform says that for up to 1 in 100 people the virus causes temporary or permanent paralysis, which can be life threatening.

Most people who get polio do not have symptoms and may not know they were infected. The NHS says some people get mild, flu-like symptoms, which usually last up to 10 days. NHS inform says that a small number of people have a flu-like illness 3 to 21 days after infection, and that these symptoms usually pass within about a week.

The NHS says that rarely, polio leads to more serious symptoms affecting the brain and nerves, such as weakness in the muscles (paralysis), usually in the legs, which can happen over hours or days. If paralysis affects the muscles used for breathing, it can be life-threatening. Most people recover and movement slowly comes back over the next few weeks, but some are left with permanent disability.

Yes. The NHS says polio spreads easily from person to person, usually through contact with the poo of an infected person, for example from not washing your hands properly and then putting them in your mouth, or from contaminated food or water. It can also spread through coughs or sneezes, but this is less common.

NHS inform says the virus can be spread from about a week before any symptoms develop until several weeks afterwards, and that infected people who have no symptoms can still pass it on. The NHS says washing your hands with soap and water regularly (or using hand sanitiser if you cannot wash) helps you avoid catching and spreading viruses.

NHS inform adds that there have been rare cases where polio was caused by a live version of the virus in a vaccine, but that this is no longer a risk in the UK because the vaccine used now contains an inactive version of the virus.

The NHS says there have been no confirmed cases of paralysis due to polio caught in the UK since 1984. Although some poliovirus has been found in sewage in recent years, the risk of getting it remains extremely low. Polio was eradicated in Europe in 2003, as the NHS notes.

The chance of becoming ill is higher if you are not fully vaccinated, which is why the NHS asks you to check that you and your children are up to date. There is still an extremely small risk of catching it when travelling in a country where polio is still found, such as Afghanistan and Pakistan, and a very small risk for unvaccinated people from contact with someone bringing the virus back to the UK.

There is no treatment that cures polio. The NHS says some types of care help lower the risk of long-term problems, including care in hospital, painkillers, fluids (rehydration treatment), help with breathing, and regular stretches and exercises to prevent problems with the muscles and joints. NHS inform describes treatment as supporting bodily functions while the body fights off the infection.

If long-term problems develop, you may need specialist help such as physiotherapy or surgery, according to the NHS. NHS inform adds that ongoing treatment may include physiotherapy, splints and braces to support weak limbs or joints, occupational therapy, and possibly surgery to correct deformities.

The NHS says polio can cause long-term or lifelong difficulties. Some people are permanently paralysed, and others have problems that need long-term treatment and support, which can include extreme tiredness, muscle weakness, problems with the joints and swallowing difficulties (dysphagia).

If you have had polio before, symptoms may return or get worse, sometimes decades later. The NHS and NHS inform call this post-polio syndrome.

The NHS says the best way to prevent polio is to make sure you and your child are up to date with vaccinations, and that the polio vaccine is part of the routine childhood vaccination schedule. You need all 6 doses to be fully vaccinated. You can check with your GP surgery, and for children and babies you can also check the personal child health record (red book). If you are not up to date, you can book an appointment with your GP surgery to be vaccinated free on the NHS.

The NHS says you can have a polio vaccination at any point if you have never had one, even if you are not travelling to a country with a risk of polio. You should also get vaccinated if you have had polio before, because the vaccine protects against different types. NHS inform explains there are 3 types of poliovirus and that people who have had the infection will only be immune to one of them.

The NHS says that if you are travelling abroad you should get advice from a travel clinic, GP, nurse or pharmacist before you go. In addition to the routine polio vaccines, you may need a polio booster before you travel if you were last vaccinated against it more than 10 years ago. Some countries require proof of vaccination (an International Certificate of Vaccination or Prophylaxis, or ICVP) before you can enter or leave.

The NHS suggests checking the risks of the country you are travelling to on the TravelHealthPro website. NHS inform names Afghanistan, Nigeria and Pakistan as places where polio is still a significant problem, and notes a potential risk in other parts of Africa and some Middle Eastern countries.

The NHS says to call 999 or go to A&E if you or your child are not able to move part or all of the body, where the body part may also feel stiff, floppy or numb, or if you or your child are having difficulty breathing or are breathless. Tell the person you speak to if you have recently travelled to an area where there is a risk of polio or have been in close contact with someone who has. Do not drive to A&E.

The NHS says to get advice from NHS 111 now if you have flu-like symptoms and you have travelled to an area with polio (even if vaccinated), you are worried about a baby's or child's symptoms, you are pregnant, you are 65 or over, you have a long-term medical condition or weakened immune system, or your symptoms do not improve after 7 days. It says to call 111 if you need help for a child under 5.

Polio vaccination is offered free on the NHS through your GP surgery as part of the routine schedule, and catch-up doses are available at any age. If symptoms of polio are suspected, the route is NHS 111, a GP or emergency care depending on the symptoms, as set out above.

Some people choose to have travel vaccination advice or boosters from a private travel clinic. If you do, make sure your NHS records are updated so that your GP surgery has an accurate list of the doses you have had.