With millions vaccinated, rare side-effects of jabs are emerging

CHRIS WHITTY, England’s chief medical officer, vividly recalls a nerve-racking moment on December 8th 2020. That was the day when England became the first country to roll out a covid-19 vaccine, a jab developed by Pfizer and BioNTech. Near midnight on vaccination day one “We were discussing it and just thinking ‘What are we dealing with here? These are small numbers and we’ve already had several dangerous near misses’,” said Dr Whitty in a recent talk at the Royal Society of Medicine. In some people, it had turned out, the vaccine sets off anaphylaxis, a life-threatening allergic reaction. But this is rare. It occurred just once among the 22,000 or so people vaccinated in the trial, which could have been by chance. Now, with hundreds of millions vaccinated, the rate at which it occurs is clearer: five per million.