Let vax-data drive policy: Data must inform any shift to a one-shot vax regime

Also needed—as the government takes a call on the senior-secondary board exams—are rigorous trials of vaccine safety and efficacy among children.

The Centre’s plan to comb data emerging from ongoing vaccination efforts for perspective that can help fine-tune its Covid-19 vaccine strategy is, without doubt, welcome. Even as India struggles with vaccine scarcity, the proposed vaccine tracker platform that—as reported by The Indian Express (IE)—will be an important tool to check the merit of decisions such as increasing the gap between the doses of Covishield (licensed from AstraZeneca by Serum Institute).

Covishield accounts for nearly 90% of vaccine-doses administered in India so far, and thus the stakes are high for a large chunk of the vaccinated (at least one dose) population, with concomitant implications for risks of spread in the country. National Technical Advisory Group on Immunisation chair NK Arora, quoted by IE, believes the platform will harmonise diagnostic data, vaccine data and overall disease data, based on which India will be estimating “vaccine effectiveness, reinfections and trends as vaccine coverage increases”.

Though late in the day—jurisdictions such as the UK already have similar tools in place—it is nevertheless an important development. India‘s vaccine strategy will need to evolve continuously and rich data from the ground will form a key element of this. With mutations that can potentially confer greater infectivity and immune-escape to the virus, there is an urgent need to tweak vaccine efforts against data on breakthrough-infections, reduced vaccine-efficacy, severity of infection post-immunisation, etc.

But, even as the government looks to study the effectiveness of a single-dose of Covishield at a time of vaccine shortages, it would do well to keep in mind the findings of Public Health England on AstraZeneca efficacy against the double-mutant (B1.617) variant. As Dr K Srinath Reddy of the Public Health Foundation of India had pointed out in an article in this newspaper (bit.ly/3vF70WF), the AstraZeneca vaccine, with caveats on sample-size, reported significant erosion of efficacy against B.1.617.2, both in a one-dose and two-dose scenario, though the performance was better in the latter case.

Drawing from this Dr Reddy had argued for the merit of a shorter dosing-interval for Covishield in India than is currently in place. Indeed, while the Centre had cited real-world data from the UK to back its longer-interval decision, the UK itself revised its interval directive for AstraZeneca to a shorter period than before. Of course, it is expected that India’s real-world tracking would shed more light; in the interim, the government needs to be mindful of emerging data from other jurisdictions while significantly stepping up efforts to analyse variants in circulation; the INSACOG initiative, as this newspaper has pointed out earlier, needs to be strengthened and its findings heeded, instead of being shrugged off as a recent Reuters seemed to suggest.

Also needed—as the government takes a call on the senior-secondary board exams—are rigorous trials of vaccine safety and efficacy among children. While a trial of Covaxin among 2-18-year-olds is to take off shortly, the government will need to marshal as many vaccine-candidates as possible to protect children’s health. It must now arrange for vaccines that have received approval in developed jurisdictions for use on children to have bridging trials here, more so since some vaccine candidates have made it clear their supply negotiations, if any, will only be with the Centre.