U.S. government scientists skeptical of one-shot regimen for Pfizer, Moderna COVID vaccines

U.S. health experts say they cannot get behind proposals to switch to single-dose regimens of the Pfizer and Moderna coronavirus vaccines, which were approved under a two-dose protocol. Seven U.S. legislators who are also physicians recently wrote a letter asking Acting HHS Secretary Norris Cochran to “consider issuing a revised emergency use authorization as soon as possible” that might allow for single-dose administrations of the two products. However, some of the government’s top scientists—from Peter Marks, MD, who oversees FDA’s vaccine office to Anthony Fauci, MD, the nation’s top infectious disease expert—argue there is insufficient evidence to support a change in practice, despite preliminary studies suggesting one injection is enough. While acknowledging that a single dose might offer some short-term protection, they note that it is unknown whether it will cover recipients over the long term—particularly as new strains of the virus emerge. “You would be flying blind to just use one dose,” warned an adviser to the president. “If you’re going to do something else other than follow the studies shown to the FDA, show me that this one-shot effect is durable.”