Poliomyelitis, often referred to as polio, is a contagious viral infection caused by the poliovirus that can lead to paralysis, breathing problems, and even death. It is spread by infected fecal matter entering the mouth through contaminated water or food.
The vast majority of people infected with the poliovirus will not experience any symptom. Only 4-8 percent of cases are symptomatic.
Polio can be prevented through the administration of the polio vaccine. There are two types of polio vaccines: inactivated poliovirus (IPV) and oral polio vaccine (OPV). The former is given in a series of injections starting two months after birth, is very safe and effective, and cannot cause polio. The other vaccine is given in other countries due to its low cost. It also provides a very high level of immunity. However, since is it an active form of polio, it can revert to the polio disease, and may even cause paralysis.
In most parts of the world, poliovirus has been eradicated. However, in Pakistan and Afghanistan, it is still widespread. Risk factors for contracting the disease include not having been vaccinated; especially young children, pregnant women, and other people with compromised immune systems.