A new polio outbreak in Sudan has been linked to the oral polio vaccine that uses a weakened form of the virus. ... WHO said two children in Sudan, one from South Darfur state and the other from Gadarif 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 showed the cases were linked to a continuing vaccine-derived outbreak in Chad that was first detected last year and is now spreading in Chad and Cameroon. While so-called vaccine-derived polio is a known...