HYDERABAD: The bivalent Oral Polio Vaccine (bOPV) vials of a batch, manufactured by Bio-Med, which was found to be having traces of Type-2 poliovirus, were supplied also to Telangana and administered to children in the State. And that leads us to the question: Are the children who were administered the bOPV at the threat of getting polio?
Officials in the Telangana Health Department said that there is no such threat as their Inactivated Polio Vaccine (IPV) -- which builds antibodies against Type-1, 2, and 3 viruses -- coverage is 85 to 90 per cent in the State which helps in protecting the remaining children.
Besides, officials said that it cannot be said conclusively that the vaccine vial of the batch sent to Telangana was contaminated with the Type-2 virus and that anything on it can be known only after tests are conducted. All bOPV vials manufactured by Bio-Med were recalled from Telangana, and they will be tested in a phased manner.
“The 85 to 90 per cent of the children who were given the IPV will help in protecting the remaining children through herd immunity. Ministry of Health and Family Welfare passed directions to give two fractional doses of the IPV to the children below two years who were not vaccinated with it. Besides, our surveillance (sewage water testing and active surveillance) is strong. If anything goes wrong, we will get to know about it,” said Dr G Srinivasa Rao, director of Public Health and Family Welfare.
The poliovirus has three serotypes -- Type-1, Type-2, and Type-3. To protect people against polio -- an infectious viral disease which mainly affects young children -- Inactivated Polio Vaccine and Oral Polio Vaccine are administered. The IPV is prepared from inactivated (killed) three serotypes of the virus.
The IPV which is given in injection form builds antibodies against Type-1, 2, and, 3 polioviruses. The OPVs are prepared by attenuating the live viruses. Trivalent OPV is used against the three serotypes of poliovirus and bOPV is used to build immunity against Type-1 and Type-3 serotypes.
India switched from Trivalent OPV to bivalent OPV (bOPV) after the Type-2 virus was eradicated from the country in the year of 2016. The bOPV is supposed to contain a mixture of only attenuated Type-1 and Type-3 viruses.
However, on September 24, Ministry of Health and Family Welfare officials informed the State Health Department officials that the B10048 batch was contaminated with Type-2 Poliovirus.
This has put officials on alert and all batches of the vaccine vials manufacture by Bio-med were recalled from shelves.
On Tuesday, a meeting was held in Delhi on the issue where directions were passed to administer two fractional doses of the IPV to all children below two-years who were not vaccinated with it.