The Ministry of Health (MoH) in Kenya is on high alert after Malawi recorded Africa’s first wild polio case earlier this year, coming two years after the continent was declared free of the strain. Before this, the last case of wild polio, one of the three strains of the virus, was reported in 1992.
The strain is endemic in Pakistan and Afghanistan, with the case detected in a child in Malawi’s capital Lilongwe in February found to be the same one that had been circulating in Sindh province in Pakistan.
Now, MoH says surveillance is ongoing in Kenya although a recommendation for a vaccination campaign is yet to be made.
According to the head of the National Vaccine and Immunisation Programme at the ministry, Dr Lucy Mecca, there is a robust polio surveillance system in place. She further stated that the last vaccine-derived polio cases were imported but the team is monitoring the situation and are on high alert.
The Malawi case comes amid concerns that countries that had previously eradicated polio in Africa, the Middle East and parts of Asia are seeing new outbreaks of vaccine-derived polio, with experts blaming it on gaps in immunisation over the recent years.
According to the World Health organization (WHO), polio is a highly infectious disease caused by a virus that invades the nervous system. It can cause permanent paralysis (approximately one in 200 infections) or death (about two to 10 percent of paralysed cases).
The virus is transmitted from person to person, mainly through the faecal-oral route or, less frequently, by a common vehicle (for example, contaminated water or food).
“Two of the three types of wild poliovirus have been eradicated (WPV2 and WPV3), with ongoing global efforts to eradicate WPV1. Currently, wild poliovirus is endemic in two countries: Pakistan and Afghanistan,” the global health agency explains in a recent statement.
“The detection of WPV1 outside the two countries where the disease is endemic demonstrates the continuous risk of international spread of the disease until every corner of the world is free of WPV1.”
WHO scientists also explain that the risk at the national level in Malawi is assessed as high given the high population density, low vaccination coverage (less than 80 percent) in many districts and lack of a catch-up campaign for more than six years.
“Furthermore, the switch from the trivalent Oral Polio Vaccine (OPV) to bivalent OPV in Malawi was completed on 25 April 2016, and Inactivated Polio Vaccine (IPV) was introduced on 14 December 2018. The most recent supplementary immunisation activities (SIAs) with a vaccine containing type 2 vaccine were conducted in 2013,” WHO says.