The reports that some 1.5 lakh vials of oral polio vaccine (OPV) distributed in Uttar Pradesh, Telengana and Maharashtra had been found contaminated by type 2 strain of polio virus, which had been declared eradicated in 2016, seem to have created some confusion amongst people in Kerala.
However, the Indian Academy of Paediatrics (IAP) and the Health Department have been quick to clarify that the news has no bearing on the immunisation programme in Kerala.
Not a single batch of contaminated OPV from the Ghaziabad-based firm, Biomed Pvt Ltd., which supplies vaccines only to the Government of India, has been distributed in Kerala. Moreover, the contamination per se does not pose a serious public health threat in Kerala or elsewhere in the country because the type 2 strain detected is a weak vaccine virus and not the wild polio virus (WPV), both the IAP and the Health Department clarified .
India declared the eradication of type 2 WPV in 2016. Following this, Kerala had successfully introduced into its routine immunisation schedule, injectable inactivated polio vaccine (IPV), which gives protection against all three types of polio viruses in April 2016.
This was followed by a globally synchronised replacement of trivalent OPV (tOPV, effective against polio types 1, 2, 3) with bivalent OPV (bOPV, effective against type 1 , 3).
On National Switch Day, on April 25, 2016, along with the nation, Kerala too phased out tOPV from its immunisation schedule, to be replaced by bOPV. “The IPV had already been introduced in Kerala and the rest of the country, before tOPV had been removed from immunisation schedule. Hence, the fear that children born in India after 2016 does not have immunity against type 2 polio strain is totally misplaced,” I. Riaz, general secretary, Indian Academy of Paediatrics, Kerala, said.