Vaccine 2.0: Moderna and other companies plan tweaks that would protect against new coronavirus mutations

News from U.S. manufacturer Moderna that its COVID-19 vaccine is still “expected to be protective” against a virus variant first detected in South Africa came as a relief to scientists and the public. But the 25 January announcement included a caveat: Antibodies triggered by the vaccine appear to be a little less potent against the new variant, named B.1.351, than the one the vaccine was developed for. So researchers were perhaps even more relieved to hear the company will start development of booster shots tailored to B.1.351 and other variants.

“These are exactly the steps that I hoped to see,” says virologist Trevor Bedford of the Fred Hutchinson Cancer Research Center. “It may well not be necessary to have a vaccine update in the fall, but taking these steps now is the right course of action.” Other vaccinemakers are also contemplating updates.

Scientists have grown increasingly concerned that new coronavirus variants may worsen the pandemic. B.1.1.7, first detected in England and now spreading globally, has been shown to be more transmissible; on 22 January, the U.K. government said it may be deadlier as well. B.1.351 and a very similar variant named P.1 that originated in Brazil’s Amazonas state are suspected of evading immunity in people who were vaccinated or previously infected.

Now, researchers from Moderna and the Vaccine Research Center at the U.S. National Institutes of Health have tested the potency of antibodies from eight people who had received the company’s vaccine against a retrovirus modified to express the mutated spike proteins of B.1.351 and B.1.1.7. In a preprint, they report that antibodies neutralized the virus in both cases. But for B.1.351, the levels needed were six times higher than for virus expressing the original protein.