(The Center Square) – The U.S. Food and Drug Administration (FDA) on Friday night granted emergency use authorization to Moderna's new COVID-19 vaccine, the second approval of a coronavirus vaccine in a week.

"The emergency use authorization allows the vaccine to be distributed in the U.S. for use in individuals 18 years and older," the FDA announced on Twitter. "The FDA has determined that the #COVID19 vaccine has met the statuatory criteria for issuance of an EAU. The totality of the available data provides clear evidence it may be effective in preventing #COVID19."

About 6 million doses of the Moderna vaccine are expected to be shipped around the country next week.

Pfizer's coronavirus vaccine, which it developed with BioNTech, was the first to receive emergency use authorization when the FDA approved it December 11. Tens of thousands of health care workers across the country have already received their first dose of Pfizer's vaccination.

Both Moderna's and Pfizer's vaccines require two doses taken a few weeks apart.

The two vaccines proved to be about 95% effective during trials.

With Friday's approval of Moderna's vaccine, more doses will be available throughout the U.S. Health care workers, and residents and staff of long-term care facilities are first in line to receive the vaccines.

AstraZenica and Johnson & Johnson also have vaccines in the accelerated approval pipeline.