- When the pandemic first struck last year out of the blue, the question on every government authority’s mind was to ensure their respective citizens are secured from the yet unknown enemy back then. The world has moved far ahead on that front what with several effective vaccine candidates being invented to thwart the fatality perpetrated by the dreaded virus to a great extent. Of course, the virulent virus is proving to be a sticky customer not showing any signs of retreating for good as new variants and strains are perpetually striking humanity across the globe.
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- Several countries are already in the midst of fourth and fifth Covid waves struggling to tame the virus even as the economies take a hit owing to unavoidable restrictions imposed. Undoubtedly, several vaccines in circulation have had an impact in restricting the severity as well as fatality but the emerging variants are posing challenges pushing for introducing booster doses to further protect the people. The Indian government is also considering introducing booster doses where two key issues appear to be emerging. When to start administering them, and which vaccines to use.
- As reported, the United Kingdom is warning of a tidal wave of Omicron cases and has advanced its booster shot targets for adults from January-end to this month’s end. Many advanced countries are also strongly pressing ahead with booster doses as well. India must also show greater urgency, recalling the still fresh horrifying devastation wreaked by the Delta variant in April-May. Note that we have nearly 5 crore citizens, 2.7 crores of them in the high-exposure or vulnerable category like healthcare workers and senior citizens, whose duration since second dosing range between six and ten months.
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- Now the question of which vaccine to boost with is proving to be more complex for the authorities. In countries recommending boosters, Pfizer’s mRNA has become the booster of choice. There is apprehension that a viral vector vaccine-like Covishield won’t offer the same protection as a booster to those already jabbed with it twice. Covishield was administered to 90% of Indian adults and its ample stocks were expected to help India’s booster effort. Meanwhile, Covaxin third dose trial results are expected shortly. If the apex technical advisory group with the mandate to recommend boosters rules out Covishield as a booster for those already dosed twice with it, the focus will automatically shift to other vaccines and their production capacities.
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- What are the options available to us then? Only two vaccines candidates viz. Covaxin and ZyCov-D have secured emergency use authorization so far. The third candidate Covovax is manufactured in India by SII and has done well in a major UK mix-and-match study with the AstraZeneca vaccine (Covishield). Also, Bharat Biotech’s intranasal vaccine Corbevax, where the government has reserved 30 crore doses, and Gennova’s mRNA vaccine in various stages of Phase 2/3 trials would be handy subsequently. Mix-and-match studies with Covishield and Covaxin should be prioritized. Here, Indian authorities must develop their research capabilities in mix-and-match studies since the Covid vaccine will become an annual affair like flu shot in the coming years. No doubt, India’s vaccination effort is entering a new trajectory, and it’s going to be complex.
