Polio is an infection caused by a virus. Polio causes fever, vomiting and muscle stiffness.
Most people with polio do not have any symptoms and do not know that they're infected. But for some people, polio causes temporary or permanent paralysis. Paralysis is the loss of the ability to move some or all of your body. The paralysis can be life-threatening.
Polio used to be common in Ireland and worldwide. It's rare today because it can be prevented with a vaccine. Cases of polio in Ireland fell when the vaccine was introduced in 1957.
The last recorded case of polio in Ireland was in 1984. But the infection is still found in some parts of the world. Because of this, there is a very small risk that polio could be brought back to Ireland.
There's no cure for polio, so it's important to make sure that you and your children are vaccinated against it.
Symptoms of polio
Most people with polio do not have any symptoms.
A small number of people experience a flu-like illness 3 to 21 days after they're infected.
Symptoms can include:
- a fever (high temperature of 38 degrees Celsius 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 a small number of cases, the virus attacks the nerves in the spine and base of the brain. This can cause paralysis, usually in the legs, that develops over hours or days.
The paralysis is not usually permanent. Movement often slowly returns over the next few weeks and months.
But some people continue to have problems. If the breathing muscles are affected, polio can be life-threatening.
Long-term problems caused by polio
Polio often passes quickly but it can sometimes cause long-term or permanent difficulties.
A few people with the infection can have some permanent paralysis. Others may have problems that need long-term treatment and support.
These problems can include:
- muscle weakness
- atrophy (shrinking of the muscles)
- contractures (tight joints)
- deformities, such as twisted feet or legs
In rare cases, people who have had polio in the past can develop symptoms again. Or, their existing symptoms can get worse. This can happen many decades after the infection. This is called post-polio syndrome.
Causes of polio
Polio is caused by a virus.
You can become infected with the poliovirus if you come into contact with:
- the poo (faeces) of someone with the infection
- the droplets launched into the air when an infected person coughs or sneezes
You can also get the infection from food or water that is contaminated with infected poo or droplets.
If the virus gets into your mouth, it travels to your throat and tummy and starts to multiply. In some cases, it can also get into the bloodstream and spread to the nervous system.
Infected people can spread the virus about a week before any symptoms show and for several weeks. Infected people who do not have any symptoms can still pass on polio to others.
There were rare cases where polio was caused by a vaccine that contained a live version of the poliovirus. This is no longer a risk in Ireland because the vaccine used today contains an inactive version of the virus.
There's no cure for polio. Treatment can reduce the risk of long-term problems while the body fights the infection.
Treatment can include bed rest in a hospital, painkillers and breathing support. Regular stretches or exercises can prevent problems with the muscles and joints.
If you continue to have problems after a polio infection, you may need long-term treatment and support.
Long-term treatment can include:
- physiotherapy to help with any movement problems
- devices such as splints and braces to support weak limbs or joints
- occupational therapy to help you adapt to any difficulties
- surgery to correct any deformities
The polio vaccine is free as part of the childhood vaccination programme in Ireland. It's given by injection in 4 separate doses.
The doses are normally given at:
- 2, 4 and 6 months of age as part of the 6-in-1 vaccine
- 4 to 5 years of age as part of the 4-in-1 vaccine
If you plan to travel to a polio-affected country, you should get vaccinated. You need to have a booster dose if it's been 10 years or more since your last dose of the vaccine.
You can also get vaccinated at any time if you haven't been fully vaccinated before.
If you had polio in the past and haven't had a vaccine, you should still get vaccinated. There are 3 types of poliovirus. People who had the infection before are only immune to one of these types.
Polio and travel
As a result of routine vaccination programmes, polio is nearly wiped out in most parts of the world. This includes Europe, North and South America, the western Pacific region and southeast Asia.
But polio is still found in some places. Polio is a problem in Afghanistan, Nigeria and Pakistan. There's also a risk of infection in other parts of Africa and some Middle Eastern countries.
Before you travel, check the polio travel advice to see if there's a risk of getting polio in a country that you plan to visit.
To leave some of the countries where there's a risk of infection, you may need proof of vaccination. If you don't have this, you may need to get a booster dose.
Content supplied by the NHS and adapted for Ireland by the HSE