Moderna vaccines promising against variants in mouse study

FILE PHOTO: A sign marks the headquarters of Moderna Therapeutics, which is developing a vaccine against the coronavirus disease (COVID-19), in Cambridge, Massachusetts, U.S., May 18, 2020. REUTERS/Brian Snyder/File Photo

Moderna Inc. vaccines designed to protect against the worrisome coronavirus variants identified in South Africa and Brazil have yielded promising results when tested in mice, according to new data.

The company tested two new approaches against the variants – a single-dose “booster” for mice vaccinated months earlier with both doses of the original Moderna vaccine, and a separate new two-shot version combining the original vaccine with the booster in mice that had never been vaccinated.

In both scenarios, according to a paper posted on Tuesday on bioRxiv ahead of peer review, the treated animals had “significant” levels of antibodies against the original strain of the virus and comparably high levels of antibodies capable of neutralizing both the B.1.351 South African variant and the P.1 Brazil variant. Tests of the two new vaccines in humans are already underway.