Three Doses Not Two: Israel sets new benchmark for full vaccination.

Redefining what it means to be fully vaccinated, every Israeli over 12 years is now entitled to a booster shot five months after the second dose. Indeed, everyone who does not get a third dose with-in six months stands to lose their green pass. Of course this largesse follows from a high-income country’s abundant access to vaccines, but it is also built upon solid vaccine science. Studies show that antibody responses weaken over time, especially in the face of new variants. So while Israel may have gone the furthest, many countries from the UK to Indonesia are on the path to offer boosters to vulnerable groups.

In India SII’s chairman has both called for a third dose and suggested the gap between Covishield doses be decreased. Rigorous local research is needed to inform these two vaccine policy questions. An Oxford University study of 3,391,645 test results has found that compared to the 92% and 69%efficacy against a high viral load seen two weeks after the second Pfizer and AstraZeneca doses, after 90 days efficacy slips to 78% and 61% respectively. Thus, at least for Covishield India can look to international studies. But with Covaxin, we are on our own.

ICMR must take the lead here but large hospitals should also step up. With more than 65.26 crore vaccine doses given till Tuesday 10pm, multiple studies will be helpful in getting an optimal handle on complex efficacy issues. The second critical factor is supply, thanks to whose improvement over a crore doses were given on both August 27 and 31. With Sputnik V’s supply disappointing so far and Corbevax’s yet to begin, GoI should top up its order of Covi-shield and Covaxin, which totals to 100.6 crore doses so far, and was last updated on July 16. Double-dosing all adults needs about 87.4 crore more doses. Then, booster shots will mean supplying even more doses.