Moderna says Covid booster appears to protect against omicron

$Moderna(MRNA.US)$ announced Monday that a third dose of its mRNA vaccine against Covid-19 appears to provide significant protection against the omicron variant.

The company said that its authorized booster can “boost neutralizing antibody levels 37-fold higher than pre-boost levels,” which it described as reassuring.

However, it also said that a double dose of the booster shot — 100 micrograms, rather than the approved 50 micrograms — was significantly more effective. A 100 microgram booster dose increased neutralizing antibody levels “approximately 83-fold,” according to preliminary data, it said in a release.

The 100 microgram dose of its booster shot was “generally safe and well tolerated,” Moderna said, though “there was a trend toward slightly more frequent adverse reactions following the 100 [microgram] booster dose relative to the authorized 50 [microgram] dose.”

Without a booster, the company’s vaccine, called mRNA-1273, was been found to be far less effective against the fast-spreading omicron variant, generating low neutralizing antibodies.

The data have not yet been peer reviewed.