Moderna trial suggests redesigned vaccines can better protect against variants

Moderna said its research showed the promise of a so-called bivalent vaccine, even against other variants besides the two versions of the virus specifically targeted. In this case, researchers combined the existing vaccine with one designed to attack the Beta variant, which was first detected in late 2020. They found the combination provided a stronger defense not only against those forms of the virus, but also against the Delta and Omicron variants, the company said.

Volunteers who got a booster shot of the reconfigured vaccine produced more than two times the level of antibodies against the Omicron variant compared with those who got a booster dose of the existing Moderna vaccine. The added protection persisted for six months against the Omicron variant but fell against Delta to essentially the same level as that elicited by the existing vaccine, the study showed.

Moderna said although Beta was an early variant, it was relevant to test because it contains several mutations that “have been persistent in more recent variants of concern, including Omicron.”