Two vaccines have been approved for public use in India. One, Covaxin, was approved without any public disclosure of data from its trials. In fact, the Phase-3 trial of the other vaccine—Covishield —doesn’t look like one either: As health expert Dr Gagandeep Kang said recently, it is “what would be called a Phase-2 study in other parts of the world, i.e. for safety and immunogenicity and not for efficacy.” Given all this, how should we react to the claims being made about these vaccines? Remember that these various trials are essentially statistical and mathematical exercises. Thus, we should examine them in those terms and no other. ‘Efficacy’, for example, is a measure of the ability of the vaccine to generate what we are all in search of, an immunity to the virus. We determine that statistically, after a large Phase-3 trial, often on tens of thousands of people. If two-thirds of them develop immunity, for example, we say the vaccine has a 67% efficacy. Only, we have no Phase-3 data for Covaxin. So, we have no way of knowing what its efficacy really is. What we have instead are claims. The Drugs Controller General of India, V.G. Somani, was quoted in the Indian Express on 6 January: “The Phase 3 efficacy trial [for Covaxin] was initiated in India on 25,800 volunteers, and till date, approximately 22,500 participants have been vaccinated across the country, and the vaccine has been found to be safe.” What do we make of this statement? To start, note that it does not address the issue of efficacy at all, even though Somani calls it an “efficacy trial”. After an “efficacy trial”, we should see language something like this: “15,000 of the 22,500 vaccinated participants—67%—have developed immunity to the virus.” Instead, we get the claim that “the vaccine has been found to be safe.” No measure of efficacy there. According to those submissions, Covaxin’s Phase-1 trial was registered on 1 July 2020. The drug was to be administered to 1,125 volunteers, and the trial had an “estimated duration” of 15 months; that is, it would run until 1 October 2021. But just over two months later, on 8 September 2020, its Phase-2 trial was registered, to run on 124 volunteers for eight months, or till 8 May 2021. The “primary outcome” for both these trials, again according to those CTRI submissions, was to check for “adverse events” and to evaluate immunogenicity; in other words, the drug’s safety and its ability to produce an immune response in volunteers. Make what you will of these declared trial durations; that we are still months away from even one of the two trials being completed; that the second trial began while the first was still in progress. But note that these tests for safety ran on a sum total of 1,249 people. We have no public data on how these people reacted to the prospective vaccine, but Somani tells us “the vaccine has been found to be safe.” In fact, he even used a number in the same news report: the vaccine is “110% safe”. What did he mean, you might wonder: that of 1,249 volunteers on whom Covaxin is being tested for safety, 1,375 showed no side-effects? The managing director of Bharat Biotech, Krishna Ella, was still more emphatic a few days earlier. ANI quoted him saying “our vaccine is 200% safe.” With all this safety apparently in the bag, Covaxin’s Phase-3 trial was registered at CTRI on 9 November. Phase-3 was intended primarily to “evaluate the efficacy” of the vaccine, while secondarily evaluating its safety and immunogenicity as well. This one was indeed for 25,800 volunteers and was to run for a duration of one year—till 9 November 2021. Make what you will, again, of this declared duration; that the Phase-3 trial began long before the Phase-1 and Phase-2 trials are scheduled to end; that we are again months away from the scheduled completion of Phase-3. But less than two months later—months before any of its three trials are concluded, without any data about those who volunteered for the trials—Covaxin has been approved for public use. In theory, all 1.4 billion of us Indians can now have it injected into us.