Polio outbreak in Sudan caused by live virus in oral vaccine, World Health Organisation says
- Sudan’s cases are linked to an ongoing vaccine-derived outbreak in Chad detected last year that is also spreading in Cameroon
- In rare instances, the live polio virus used in the oral vaccine can mutate into a form capable of sparking new outbreaks
In a statement this week, the UN health agency said two children in Sudan – one from South Darfur state and the other from Gedarif state, close to the border with Ethiopia and Eritrea – were paralysed in March and April. Both had been recently vaccinated against polio. The WHO said initial outbreak investigations show the cases are linked to an ongoing vaccine-derived outbreak in Chad that was first detected last year and is now spreading in Chad and Cameroon.
“There is local circulation in Sudan and continued sharing of transmission with Chad,” the it said in a statement, adding that genetic sequencing confirmed numerous introductions of the virus into Sudan from Chad.
The WHO said it had found 11 additional vaccine-derived polio cases in Sudan and that the virus had also been identified in environmental samples. There are typically many more unreported cases for every confirmed polio patient. The highly infectious disease can spread quickly in contaminated water and most often strikes children under 5.
In rare instances, the live polio virus in the oral vaccine can mutate into a form capable of sparking new outbreaks.
Last week, the WHO and partners declared that the African continent was free of the wild polio virus, calling it “an incredible and emotional day.”