Moderna says there is clear risk that existing vaccines are less effective against Omicron

Stephen Hoge, president of Moderna Inc., said there is a clear risk that existing COVID-19 vaccines will be less effective against the Omicron variant, although it is too early to say by how much.

If the effectiveness is shown to be less than half that, an updated formulation will probably be needed, Hoge said on ABC’s “This Week” on Sunday.

“I think there’s a real risk that we’re going to see a decrease in the effectiveness of vaccines,” Hoge said. “I don’t know how much that is enough.”

“Are we going to see something more like a 50% reduction in efficacy, which would really mean we’d probably need to reboot vaccines and update them?”

Financial markets were shaken last week when top Moderna Inc. executives said multiple mutations of the Omicron variant suggested new vaccines would be needed. Chief executive Stefan Bunsell told the Financial Times that he thinks “there is no world” in which the current shot will be as effective as the delta version.

Hoge said he “may have used different terms, but I think the short answer is that we don’t have the data to know for sure yet.”