https://www.scientificamerican.com/article/moderna-covid-vaccine-becomes-second-to-get-u-s-authorization/

A week after granting an emergency-use authorization for the country’s first COVID-19 vaccine, US regulators have followed with a second: another RNA vaccine, this one made by Moderna of Cambridge, Massachusetts.

The emergency-use authorization followed quickly after a panel of external advisers to the US Food and Drug Administration (FDA) voted unanimously, with one abstention, to recommend use of the vaccine on 17 December. One week earlier, the agency authorized a similar vaccine made by Pfizer of New York City and BioNTech of Mainz, Germany, about a week after UK regulatory authorities did the same.