Washington, Dec 21 (IANS): American biotechnology company Moderna announced Monday that preliminary data suggests its Covid-19 booster shot appears to increase antibody levels against the Omicron coronavirus variant.

The currently authorised 50-microgram booster of Moderna's Covid-19 vaccine mRNA-1273 increased neutralising antibody levels against Omicron about 37-fold compared to pre-boost levels, and a 100-microgram booster dose increased neutralising antibody levels about 83-fold, Xinhua news agency quoted the company as saying.

A 100-microgram booster dose was "generally safe and well tolerated," according to the company. But there was a trend toward slightly more frequent adverse reactions following the 100-microgram booster dose relative to the authorised 50-microgram booster dose, said the company.

To respond to the highly transmissible Omicron variant, Moderna will continue to rapidly advance an Omicron-specific booster candidate into clinical testing in case it becomes necessary in the future, said Stephane Bancel, Chief Executive Officer of Moderna.

The Omicron variant, which is possibly more contagious than the Delta variant, had been found in at least 47 US states as of Sunday, since the first case in the country was detected in California on December 1.