Who gets polio and who is at risk of the disease?
Where there are poor socio-economic circumstances and poor sanitation and hygiene, the virus is potentially present year-round. If polio is endemic, people can acquire a natural immunity since they are exposed to it as children, often getting the mild form of the illness. In these circumstances, the paralytic form of polio is usually seen only in children less than five years old. In outbreaks in nave (previously unexposed) populations, the disease will affect all age groups. The disease spreads primarily through the “faecal-oral route”. In the context of an outbreak this usually means that infected faeces has contaminated the drinking water supply. It can also spread within households through poor hygienic practices that allow faeces to contaminate food or drink.