Review of Covishield dose-interval is welcome; to quell controversy, let independent experts appraise evidence cited
Against the backdrop of senior scientists saying the NTAGI didn’t have enough data to back the recommendation to increase the gap between two doses of the Covishield vaccine from 8-12 weeks to 12-16 weeks, chairman NK Arora has said the government is reviewing the move. The scientists were quoted on the inadequate data in a Reuters report earlier this week. The government has denied this, saying the decision was unanimous and there were no dissenting scientists. It has cited the minutes of meetings of the Covid-19 working group of the NTAGI on May 10 and the Standing Technical Sub-Committee of NTAGI on May 13. While the working group’ recommendation was “based on real-life evidences particularly from the United Kingdom”, increasing the interval between the two doses to 12-16 weeks, the technical sub-committee had talked of “an interval of a minimum three months” (or roughly 12 weeks), as per a government release. The government is yet to clarify whether it had endorsed a gap of 12-16 weeks, and if it didn’t, how it settled on 16 weeks as the maximum interval. The example of Spain has been cited with regards to the 16-week gap. However, the fact is Spain recommended the 16-week interval only for those under 60 years of age. The controversy can be quelled if independent experts can examine real-life evidence that the government says corroborates the scientific strength of India’s decision. Right now, the Centre can’t afford further trust deficit over vaccines. The deadly second wave has had the unfortunate consequence of stoking vaccine hesitancy because of breakthrough infections, despite these being a very small number. As such, even if it manages to get NTAGI scientists to put up a ‘unanimous front’, it needs to do much more to engender trust.
Around the time the Indian government announced the 12-16 weeks gap, the UK had reduced the interval between two doses of the AstraZeneca vaccine from 12 weeks to 8 weeks at the maximum. This was done in light of the increasing prevalence of the Delta variant—it now accounts for 98% of the cases in the country. Bear in mind, the Delta variant is widely held to have been one of the primary factors behind India’s deadly surge. Data from Public Health England analysed by researchers, as Dr Srinath Reddy of PHFI has pointed out in this newspaper, show a single-dose of AstraZeneca—with caveats on the sample size—registers a very low efficacy against Covid-19. Two doses, on the other hand, offer reasonable protection, making a strong case for shortening the dose-gap. Thus, if the government is indeed considering a review of the interval, it is good news. In the interim, it must consider narrowing the interval for those who are more vulnerable to the disease, because of their age or immunocompromised status. Those arguing against further categorisation for targetting vaccines would do well to keep in mind the government only recently created a category for prioritisation of vaccines: students up for admission abroad. The INSACOG episode—Reuters reported how the ministry and some scientists within INSACOG were not on the same page initially regarding the seriousness of the threat from the Delta variant—and now the NTAGI episode underscore the need to let science drive the response to the pandemic, not concerns of the politically-minded.