Poliomyelitis (polio) in the South-East Asia Region

Poliomyelitis (polio) is a highly infectious viral disease, which mainly affects young children. The virus is transmitted through contaminated food and water, and multiplies in the intestine, from where it can invade the nervous system. Many infected people have no symptoms, but do excrete the virus in their faeces, hence transmitting infection to others.

Initial symptoms of polio include fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs. In a small proportion of cases, the disease causes paralysis, which is often permanent.

Polio can only be prevented by immunization. The vaccines currently being used are oral poliovirus vaccine (OPV) and inactivated poliovirus vaccine (IPV). OPV is given by mouth as drops and IPV is given by injection.

There are three types of wild polioviruses (WPV) - types 1, 2 and 3 - that can cause polio. Global eradication of WPV2 was certified in 2015. No case due to WPV type 3 (WPV3) has been detected globally since 10 November 2012. The transmission of WPV type 1 (WPV1) is limited to two countries in 2018–2019.