Moderna says booster of its Covid vaccine appears to protect against omicron

Empty bottles of Moderna Covid-19 vaccine are pictured in a vaccination center in Garlan, western France, on December 13, 2021.

FRED TANNEAU | AFP | Getty Images

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

However, it said it will also continue to develop an omicron-specific booster candidate which should enter clinical trials in early 2022.

Modern said that its currently 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 doze 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 the release.

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

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

The data has not yet been peer reviewed.

It comes as the World Health Organization warns omicron cases can double every 1.5 to 3 days in areas of local spread. The U.K. recorded its highest daily case levels since the start of the pandemic in the last week, and the Netherlands imposed a strict full lockdown on Sunday extending past the new year.