Polio, short for poliomyelitis, is a serious infectious disease caused by the poliovirus. The poliovirus can be divided into three subtypes: type 1, 2 and 3. The severity of symptoms is dependant on the subtype with which people have been infected. Most people with polio don’t have any (severe) symptoms. However, in some cases, polio can be very harmful and cause serious conditions. The incubation period of polio is typically one to two weeks. The time between infection and the first impact may take longer, but is never more than 35 days. Cases of polio in the Netherlands are now very rare, but do occasionally occur in areas where people were not vaccinated. Polio does occur in countries with a low vaccination rate.
About 95% of people with polio won’t have any symptoms. A small number of people will experience flu-like illness. These symptoms usually pass within a week. In rare cases, symptoms are more severe and cause headache, muscle aches and vomiting whilst the virus spreads to the spinal cord and attacks the nerves and sometimes the base of the brain. This can cause paralysis, usually in the arms or legs. In some cases the breathing muscles are affected, which can be life threatening. In very rare cases polio causes permanent paralysis. A small number of people who have had polio (20 to 30%) develop post-polio syndrome where some the former symptoms return or get worse many years after the original polio infection. Post-polio syndrome is characterized by muscle pain, muscle weakness and fatigue.
Polio: infection and treatment
Poliovirus is usually spread from person to person. You can become infected with the poliovirus if you come into contact with the poo (faeces) of someone with the infection, or with the droplets launched into the air when they cough or sneeze, and even by talking to an infected person. Good personal hygiene, such as washing hands, is thus important to limit the distribution of polio. There are no medicines against polio. Patients are often hospitalised; in other cases, a period of bed rest is sufficient. The recovery period often includes physiotherapy. Most people fully recover from polio but sometimes paralysis is permanent.
The polio vaccination is an effective means to protect people against the poliovirus. Those who have had a series of three vaccinations are protected for life. If this is the case, a booster vaccination is not required. The vaccine against polio is usually given in combination with vaccines against diphtheria, tetanus and, in children, pertussis, and is also known as the DTP vaccine. People who have suffered from polio in the past are only protected against the subtype with which they were infected. People who travel to a country where polio is prevalent and who are not (yet) fully vaccinated (young children, for example) are advised to get the DTP vaccine prior to their trip.