World Sees Spike In Polio Cases Due To Oral Vaccine

The fight against polio through massive vaccination efforts since 1988 has helped reduce the number of cases by more than 99 per cent worldwide—but there remains a worry. Instances of vaccinederived poliovirus (VDPV), caused by the virus strains used in the vaccine by regaining their ability to cause the paralytic disease, have seen a spike between 2010 and 2019.

- Anshika Ravi

At least 149 cases of immunodeficiency VDPV (iVDPV) had been reported to the World Health Organization (WHO) between January 1961 and December 2019, says the agency’s Weekly Epidemiological Record released on July 17. While the number itself might look small, the rate at which it is increasing is worrying. At least two out of three cases (66 per cent) reported so far were detected between 2010 and 2019. Of these, 59 per cent occurred in children under two years of age. At least 60 per cent cases were reported in males and 64 per cent patients had Acute Flaccid Paralysis (AFP), the most severe sign of polio, as the first symptom.

During July 2018-December 2019, 16 new iVDPV cases were reported from five countries—Argentina, Egypt, Iran, the Philippines and Tunisia.