With vaccine supplies stagnant even as demand is expected to skyrocket amid vaccination for the 18-45 age group commencing on May 1, a good option is to expand the gap between the two Covishield doses. Accounting for over 90% of doses so far, Covishield will remain the mainstay of India’s vaccination programme, until other vaccines step up. If implemented, this expansion will be the second one since March 22, when the Centre increased the 28-day dosing gap to 4-8 weeks after its experts ruled that a 6-8 week gap enhanced protection.
But United Kingdom, the other big country that bet big on the same vaccine, had recommended a 12-week gap. In March, Canadian vaccinologists proposed a four-month interval for all vaccines to maximise first doses. AstraZeneca’s Phase 3 trial data from the UK supported a larger dosing gap, noting 81.3% efficacy when administered 12 weeks apart, trumping efficacy for the 4-week dosing interval in both the UK and US trials. The 12-week gap has helped the UK single-dose 49.4% of the population by now. From January to March, this strategy gave the country several weeks leeway to stockpile for the second dose. Meanwhile, studies indicate lower fatalities even among those who have just received one dose. In Mumbai too, the lower death toll among elderly in this wave signifies that one dose is better than none.
Nearly a third of the vaccine doses administered in India in recent days are second doses. A 12-week gap would significantly reduce second dosers and allow more people to get their first doses, while new capacity is added. Otherwise, with Serum Institute reportedly in no position to supply many states before May 15, a long wait beckons the 18-45 age group, comprising most of the workforce. In this dire situation, extending the Covishield dosing gap is a win-win strategy.
This piece appeared as an editorial opinion in the print edition of The Times of India.
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