The case, which marks the second imported case of wild poliovirus in southern Africa this year after an outbreak in Malawi in February, was discovered in the child who began to experience the onset of paralysis towards the end of March, said the WHO.
“The detection of another case of wild poliovirus in Africa is very concerning….It shows how dangerous this virus is and how fast it can spread,” said Matshidiso Moeti, WHO Regional Director for Polio. Africa, in a press release.
Polio invades the nervous system and can cause irreversible paralysis within hours. It cannot be cured, but the infection can be prevented by vaccination – and the dramatic reduction in cases worldwide in recent decades is due to intense national and regional infant and child vaccination campaigns.
WHO is supporting large-scale vaccinations targeting millions of children in southern Africa to halt the spread of the virus on the continent, which was declared indigenous wild polio-free in 2020 after eliminating all forms of the wild virus in Africa .
Genomic sequencing suggests the newly confirmed case is linked to a strain that began circulating in Pakistan in 2019, similar to the case reported in Malawi this year, the WHO added.
In unvaccinated populations, polio viruses can reappear and spread rapidly. Vaccine-derived polio cases can also occur in places with low immunity and poor sanitation because vaccinated people can shed the virus, putting unvaccinated people at risk.