United States-based pharmaceutical company Moderna announced on Monday that a booster shot of its vaccine raised the level of antibodies against the Omicron variant of the coronavirus.

In a statement, Moderna said that the currently authorised booster dose of 50 micrograms of its vaccine increased the level of antibodies by roughly 37-fold. A full dose of 100 micrograms was even more effective, raising antibody levels about 83-fold compared to pre-boost levels, the company added.

It is not clear what the results mean in ascertaining how well the booster shots can work against the Omicron variant. The data has also not yet been peer reviewed.

But, Moderna’s Chief Executive Officer Stephane Bancel described the data as “reassuring”.

The Omicron variant is spreading fast across the world. The World Health Organization had said on December 17 that number of cases of the variant is doubling in 1.5 to 3 days in areas with community transmission. The new strain has been detected in 89 countries as of December 16, according to the global health body.

In its statement, Moderna said it was assessing the booster shots in a study comprising approximately 300 to 600 participants. The results were based on samples of 20 participants who each received the booster shots of 50 and 100 micrograms.

The company was also testing the effectiveness of Omicron-specific vaccine candidates. The statement said that the vaccine candidates showed similar efficacy.

It added that the 100 microgram booster dose of its authorised vaccine was safe and well tolerated.

“The frequency and nature of solicited systemic and local adverse events seven days after receiving a booster were generally comparable to those seen after the two-dose primary series,” the statement said. “There was a trend toward slightly more frequent adverse reactions following the 100 µg booster dose relative to the authorized 50 µg booster dose of mRNA-1273 [authorised vaccine].”

The company said that it will continue to develop an Omicron-specific variant vaccine.

“We will also continue to generate and share data across our booster strategies with public health authorities to help them make evidence-based decisions on the best vaccination strategies against SARS-CoV-2,” Bancel said.

In the US, regulators had approved the 50 microgram booster of Moderna’s vaccine in October. The first two shots of its vaccine are both 100 micrograms.

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