In October, the Centers for Disease Control and Prevention recommended that high-risk adults get a second updated Covid vaccine to bolster their protection against the virus. No other vaccines are given at such a high frequency, but experts say there’s no reason to believe that the vaccines — and in particular, the mRNA vaccines from Pfizer and Moderna — aren’t effective. Pfizer’s and Moderna’s vaccines were the first to use mRNA technology to induce immunity to a virus, an approach that proved critical in the early days of the pandemic because mRNA vaccines can be developed much faster than traditional vaccines. Despite the CDC recommending an additional shot, there’s no evidence that the mRNA vaccines aren’t working as expected, said Akiko Iwasaki, a professor of immunology at the Yale School of Medicine. In a perfect world, the Covid vaccines would be able to be updated much faster to match the strains in circulation.

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Persons: Akiko Iwasaki, Iwasaki, —, ”, Ashish Jha, ” Jha, “, Jha, I’ve, “ Topping, John Wherry, ” Wherry, Anna Durbin, ” Durkin, we’ll Organizations: Centers for Disease Control, Pfizer, Moderna, CDC, Yale School of Medicine, Emory University, Brown University School of Public Health, White, University of Pennsylvania, Johns Hopkins University School of Medicine