Union Health Minister Dr Harsh Vardhan on Wednesday reacted to the continuing controversy over the government's decision to double the interval between two doses of the Covishield coronavirus vaccine. When administration of Covishield initially began, the gap between the two doses was 28 days. This was subsequently raised to six to eight weeks and finally to 12 to 16 weeks on May 13. Critics alleged the move was linked to shortage of vaccine stocks.
Taking to Twitter, Harsh Vardhan wrote on Wednesday, "Decision to increase the gap between administering 2 doses of COVISHIELD has been taken in a transparent manner based on scientific data. India has a robust mechanism to evaluate data. It's unfortunate that such an important issue is being politicised!"
Harsh Vardhan also attached a press release of an interview given to DD News by Dr N.K. Arora, the chairman of the country's COVID-19 working group of the National Technical Advisory Group on Immunisation (NTAGI).
Arora told DD News the move to raise the gap between the Covishield doses "lay in the fundamental scientific reason regarding behaviour of adenovector vaccines”. Arora was quoted as telling DD News, “In the last week of April 2021 the data released by Public Health England, United Kingdom’s executive agency of the Department of Health, showed that vaccine efficacy varied between 65% - 88% when interval is 12 weeks. This was the basis on which they overcame their epidemic outbreak due to the Alpha variant. The UK was able to come out of it because the interval they kept was 12 weeks. We also thought that this is a good idea, since there are fundamental scientific reasons to show that when interval is increased, adenovector vaccines give better response. Hence the decision was taken on May 13, to increase the interval to 12-16 weeks.”
Arora emphasised, "We have a very open and transparent system where decisions are taken on scientific basis. The COVID Working Group took that decision, with no dissenting voice. This issue was then discussed threadbare at an NTAGI meeting, again with no dissenting notes. The recommendation was that the vaccine interval has to be 12-16 weeks.”
Arora's reference to there being no 'dissenting' voice appears to have been prompted by a report in Reuters on Tuesday. Reuters reported that three members of the NTAGI said the body did not have enough data to make a recommendation to raise vaccine interval to 12-16 weeks.
M.D. Gupte, a former director of the state-run National Institute of Epidemiology, said the NTAGI "had no data concerning the effects of a gap beyond 12 weeks". Gupte told Reuters, "Eight to 12 weeks is something we all accepted, 12 to 16 weeks is something the government has come out with. This may be alright, may not be. We have no information on that."
Two other NTAGI members, Mathew Varghese and J.P. Muliyil, said the body had not recommended stretching the dose gap for Covishield to 12-16 weeks.
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Interestingly, Arora had told DD News that discussions were under way since mid-May on whether to revert to the four-eight week interval for Covishield doses.