: Polio virus was detected in the city's sewers again, the second time this year. Advising against panic, the State government suspects unauthorised use of an older vaccine as the source of the virus.
The Commissioner of Health and Family Welfare received results of tests from Mumbai's Enterovirus Research Center on Wednesday about two samples collected at Nagole and Amberpet Sewerage Treatment Plant containing the virus. A sample from Amberpet had tested positive in May this year.
"We received word that it was a vaccine virus. We will now check to see if the older trivalent oral polio vaccine is still being used," said Dr. G. Srinivas Rao, Telangana's Chief Programme Officer, National Health Mission said.
In May, a sewage sample from Amberpet was found to have vaccine-derived polio virus type 2 (VDPV) which had mutated 10 base pairs from the live virus used in tOPV. The virus was presumed to have been shed by a child immunised with OPV in the last one year. The virus this time is exactly what is used in the vaccine, without mutations. This has led the government to suspect use of tOPV, which the Indian government has prohibited after April 25 this year. Instead, the center mandated use of bivalent (containing only type 1 and type 3 polio viruses) instead of trivalent (also containing type 2) as India has been free of wild polio virus types for many years now. The shift from tOPV to bOPV was required to prevent type 2 virus in the vaccine causing infections.
As part of the shift, the manufacture, distribution and sale was to be stopped but the recent detection of the virus hints at the existence of the old vaccine.
In an emergency meeting convened on Thursday, the State government has decided to check all private and public health institutions, besides requiring them to declare their status vis-a-vis tOPV.
