What is polio?
Poliomyelitis (polio) is a highly infectious disease caused by the poliovirus. It can be preventable via vaccination. Poliovirus invades the nervous system, and can cause total paralysis in a matter of hours. It can strike at any age, but mainly affects children under 3 years old.1
Most people infected with the poliovirus have no signs of illness. Symptomless people can spread the infection to thousands of others before the first case of polio paralysis emerges. When symptoms do occur they can range from a mild illness with fever, to meningitis or paralysis.2
The following is a summary about the disease. For further details speak to your local pharmacist or GP.
‘Wild’ polio infection:
The naturally occurring poliovirus is known as ‘wild virus’. It can be spread via:
The virus enters the mouth and travels to the throat and bowels, where it starts to multiply. In some cases, it can also enter the bloodstream and spread to the nervous system.
The virus can be spread by someone with the infection from about a week before any symptoms develop, until several weeks afterwards.
Approximately 95% of infections are mild (flu-like symptoms) or asymptomatic. Infected people who do not show any symptoms can still pass polio on to others.
Polio associated with vaccines:
1. Vaccine-associated paralytic polio (VAPP):
Rarely, the live attenuated vaccine virus in oral polio vaccine (OPV) can cause paralysis – either in the vaccinated child, or in a close contact.3 Due to this, many countries including the UK are now using the inactive (injected) vaccine for this reason.2
2. Vaccine-derived polioviruses (VDPVs):
Additionally, rarely, a strain of poliovirus in oral polio vaccine may genetically change so that it can both cause paralysis and circulate among a population.3
As a result of routine vaccination programmes, polio has been largely wiped out in most parts of the world.
Areas declared polio-free by the World Health Organization (WHO) include Europe, the Americas, the western Pacific region and, most recently, southeast Asia.
It’s still a significant problem in Afghanistan, Nigeria and Pakistan. There is a potential risk of infection in other parts of Africa and some Middle Eastern countries.4
Further details of countries endemic for wild poliovirus can be found here.5
People with polio who are asymptomatic will fight off the infection.
A small number of people will experience a flu-like illness 3-21 days after infection.1
Symptoms last for approximately a week and may include:
In less than 1% of cases, the polio 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 isn’t usually permanent, and movement will often slowly return over the next few weeks and months. Some people are left with persistent problems. If the breathing muscles are affected, it can be life threatening.
Although polio often passes quickly without causing any other problems, it can sometimes lead to persistent or lifelong difficulties. About 1 in every 200 people with the infection will have some degree of permanent paralysis, and others may be left with problems that require long-term treatment and support.
These can include:
There’s also a chance that someone who’s had polio in the past will develop similar symptoms again, or worsening of their existing symptoms, many decades later. This is known as post-polio syndrome.
Complications of paralytic polio
There is currently no cure for polio. Treatment focuses on supporting bodily functions and reducing the risk of long-term problems.
Management of acute paralytic polio includes:
An effective vaccination against polio is available. In addition to vaccination, travellers should ensure good personal hygiene and follow advice on prevention of food and water-borne diseases.
Polio vaccine is recommended for:
The polio vaccine is now only given as part of combined products:
These vaccines are inactivated, do not contain live organisms and cannot cause the diseases against which they protect. It can therefore be given safely to people with immunosuppression (including those with HIV) and to pregnant and breast-feeding women.
Childhood vaccination programme:
The polio vaccination is offered as part of the NHS routine childhood vaccination programme. It’s given by injection in 5 separate doses. These are normally given at:
If planning to travel to a polio-affected country, travellers should get vaccinated if they have not been fully vaccinated before. If it has been more than 10 years since the last dose, a booster dose is required.
This information is taken from trusted third party websites, NaTHNaC (Travel Health Pro) and EMIS (Patient info) and use of all information has been licenced under the Open Government. Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
Although the materials are being used/replicated under the provisions of the Open Government Licence this in no way represents endorsement of Traveljab.co.uk by NaTHNaC, Emis, Public Health England, the NHS or the Department of Health and Social Care.