India’s vaccine strategy needs transparency
Isn't it odd the Oxford-AstraZeneca vaccine - known to us as Covishield - is our main one and yet we are uninformed of the international debate about its efficacy and dosage? I'm not referring to the confusion created by AstraZeneca's results when it claimed 62% efficacy after two full doses, but 90% after half a dose followed by a full one. Even though unresolved, that's slipped into history. My concern is two recent issues and the fact that our government hasn't said a word about them.
The first is an official guidance issued by the World Health Organization on February 10: "In the light of the observation that two-dose efficacy and immunogenicity increase with a longer interval, WHO recommends an interval of 8 to 12 weeks between the doses".
Gagandeep Kang, perhaps our top vaccine scientist, has explained the reasons behind this. Because of delays in availability of the second dose, 59% of the efficacy trial sample got the second dose between four and eight weeks after the first, 22% between nine and 12 weeks and 16% after 12 weeks. Their vaccine efficacy was 56%, 70% and 78% respectively. This, she concludes, indicates "a clear trend of increasing efficacy with longer intervals between doses". When the immune response is included, "it was found that the longer the intervals between the two doses, the better were the human response".
So, clearly, there's good evidence for this guidance. It also makes sense for three other reasons. A longer interval means more people can receive a vaccine quickly. If more people get it, we would be better protected if a second wave--God forbid--happens. And with cases and deaths sharply declining, we're in a position to increase the interval.
Yet, on this issue the government is silent or, if it's spoken, it's done so sotto voce. Why? This is a matter on which I would expect a carefully thought-out, if not also confident, opinion. Moreover, it needs to be widely known. Silence feels like irresponsibility. The second issue is more complex, but the government's lack of response remains perplexing. It's to do with the efficacy of AstraZeneca for people over 65. Because only one-tenth of the participants in the efficacy trials were older than 65, Germany and Denmark have decided not to give it to this age group.
Commenting on this, Kang writes that for over-65s, the trial showed "a vaccine efficacy of 52%", which isn't great. More importantly, "the numbers are too small for firm conclusions". Spain, Italy and Belgium, it seems, have gone one step further. They've decided not to give AstraZeneca to anyone over 55. Switzerland is not giving it at all.
Now, these are countries that have alternatives with proven efficacy for the over-65s. We don't. Our alternative is Covaxin, and its efficacy is yet to be proven. Fortunately, WHO has come to a very different conclusion. Its guidance says: "WHO recommends the vaccine for use in persons aged 65 years and older". Kang explains it's done so after considering both immunogenicity and efficacy. So there's no reason why we should not give it to this age group.
But - and this is my point - should we not have informed our 65-year-olds of the European concerns and discussed them? Don't our elderly have a right to be informed and then reassured? Leaving them unaware is not what one expects of a democratic government.
Let me end by raising two other unconnected issues. France has decided to only give a single dose of any vaccine to people who've had Covid-19. As Kang puts it, it believes "an infection and one vaccination are equivalent to two doses of the vaccine". Is this something we should consider too?
Second, given vaccine hesitancy, should we shift focus to districts with a worrying number of cases rather than continue with a nationwide rollout? Has this been thought about? If it has, I'd like to know why it was considered inadvisable.
Karan Thapar is the
author of Devil's Advocate:
The Untold Story