A little over 392 million doses of vaccine have been administered globally, according to the Bloomberg Vaccine Tracker , with India accounting for around 9% of them. In the last week, there have been a flurry of reports from Europe, of blood clots developing in a very small fraction of those vaccinated and leading to a cascade of European countries announcing a temporary halt to their vaccination programmes involving the AstraZeneca (AZ) vaccine. WHO and the European Medicines Agency have underlined that there is no causal link between vaccines and the occurrence of such clots. In fact, there are less than 40 such occurrences reported so far, and that is much below the background of about 1,000 to 2,000 blood clots every single day in the general population, say studies based on the U.S. population. These organisations advocate that the ongoing vaccination drives continue, even accelerate, as the rate of vaccination is not keeping pace with what is required to control the pandemic. However, there are good reasons too for the countries to have called for a temporary halt. The AZ, Pfizer and Moderna vaccines have been released under emergency use authorisations, meaning that the entire profile of risks associated with them have not been thoroughly studied. History is replete with instances of vaccines that have been taken off even years after approval after a slight increase in untoward complications. As of now, the risk of dying from serious COVID-19 far outweighs that from vaccine reactions and it is such a calculation that weighs on the minds of regulators before approving vaccines.
Unlike drugs administered to the sick, vaccines have a higher bar of proving themselves safe as they are given to the healthy. Regulators of all countries rely on the experiences of others, as exemplified in India alone where it was AZ trials in the United Kingdom that paved the way for approval in India. Therefore, a warning in one country must immediately activate the sensors in another. India has a long experience with vaccinations as well as expertise in evaluating risk; however, transparency and prompt data sharing, thereby building public trust, is not one of its strong suits. This was evidenced by the approval of vaccines in spite of scant efficacy data. There is almost no information by the National Committee on Adverse Events Following Immunisation on the nature of serious adverse events following immunisation. This is in contrast to the frequent analyses shared by organisations such as the U.S. Centers for Disease Control and Prevention on adverse events. Public trust is a key ingredient to successful vaccination programmes and this can be only earned by the government’s zealous attention to allaying concerns.
