Moderna Says Covid-19 Booster Dose Works Against Omicron Variant in Lab Tests

Moderna Inc. said a third dose of its Covid-19 vaccine increased immune responses against the Omicron coronavirus variant compared with two doses in lab tests, signaling the shot could still offer protection despite the variant’s mutations.

The findings, reported by Moderna on Monday, were the latest positive—though preliminary—results from lab tests suggesting boosters can protect against the worrisome new strain.