A vaccination campaign targeting 23 million children has kicked off in Malawi and neighboring countries to contain an outbreak of wild polio declared last month, the World Health Organization (WHO) says.
Malawi confirmed a fresh outbreak of the virus — the first in the country for 30 years — on 17 February after a three-year-old girl developed acute paralysis, triggering concerns of a major outbreak.
The wild poliovirus type 1 case was genetically linked to samples of patients analyzed in 2020 in Sindh, a province of Pakistan where this type of the virus is endemic.
This campaign is not the usual immunization where health workers are at a health facility and wait for children to come.”
Janet Kayita, WHO
There are three variants of wild or naturally occurring poliovirus. Types 2 and 3 have been eradicated, while type 1 remains endemic in Pakistan and Afghanistan.
"Polio is a highly infectious and an untreatable disease that can result in permanent paralysis," said Matshidiso Moeti, WHO regional director for Africa, announcing the vaccination drive that started on Sunday.
"In support of Malawi and its neighbors, we are acting fast to halt this outbreak and extinguish the threat through effective vaccinations."
The vaccination campaign will deliver more than 80 million doses of bivalent oral polio vaccine to children under five in Malawi and neighboring countries Mozambique, Tanzania and Zambia over the coming months.
The move comes two years after Africa was certified free of the indigenous wild poliovirus, which most often spreads through fecal matter taken into the mouth via contaminated food or fingers.
The WHO says that surveillance has been stepped up in Malawi, starting in the capital Lilongwe where the new case was detected and across 11 sites in the cities of Blantyre, Mzuzu and Zomba.However, no further new cases have been detected.
"To make sure we are not missing any cases, all health workers are on high alert," said Janet Kayita, the WHO representative for Malawi, explaining the country's three-pillar response to keep the outbreak in check, which also includes strengthening routine vaccination.
"This campaign is not the usual immunization where health workers are at a health facility and wait for children to come," she added, describing it as a "house-to-house active outreach" in all of Malawi's 29 districts where health workers are also tasked to identify children who might have missed their previous routine vaccines or have symptoms suggestive of polio.
"The idea is to reach every child, everywhere, including the communities living across the border,'' explained Kayita, adding that children will be inoculated regardless of their previous immunization status.
The first phase of the four-round campaign will target 9.4 million children in Malawi, Mozambique, Tanzania and Zambia, while three subsequent rounds starting in April, June and July will also include Zimbabwe, according to the WHO.
Elisha Osati, an internal medicine specialist and honorary lecturer at Muhimbili University of Health and Allied Sciences in Tanzania, welcomed the move. She believes that significant gains made over the years in taming the virus could be reversed if Africa does not act swiftly.
"For a continent that had already defeated wild poliovirus, the element of cross-border vaccination which is included in this vaccination campaign is key," said Osati.
"This strain of the poliovirus is still endemic in Afghanistan and Pakistan. Now that it has been detected in Malawi, it means that the risk of cross-border spread is still high. From now on, the effort should focus on making sure all corners of the world are free from this virus."