A day after the FDA’s Vaccines and Related Biological Products Advisory Committee lent its support to Moderna Inc.’s COVID-19 vaccine, the agency has granted it emergency use authorization (EUA).

About 20 million doses will be delivered by the end of December and the rest in the first quarter of 2021, according to Moderna.

Moderna's vaccine is the second to receive an EUA, following the Dec. 11 award to Pfizer Inc. and Biontech SE for BNT-162b2. Both are products of mRNA technology and both posted similar efficacy numbers. The Moderna vaccine, to be administered in two doses one month apart, is for those age 18 and older while the Pfizer-Biontech vaccine is for those age 16 years and up.

“Through the FDA’s open and transparent scientific review process, two COVID-19 vaccines have been authorized in an expedited timeframe while adhering to the rigorous standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization that the American people have come to expect from the FDA,” said FDA Commissioner Stephen M. Hahn.

The European Commission exercised an option to buy another 80 million doses of mRNA-1273 on Dec. 18, bringing its confirmed order commitment to 160 million doses. The first deliveries of mRNA-1273 to European countries are expected in early 2021 if approved by the EMA.

The Moderna vaccine candidate is based on the SARS-CoV-2 spike glycoprotein antigen encoded by RNA and formulated in lipid nanoparticles.

Safety and efficacy data from an ongoing phase III randomized, double-blinded and placebo-controlled trial of the candidate in about 30,400 participants were offered as support for the EUA. With a median follow-up of greater than two months following the second dose, it demonstrated a vaccine efficacy of 94.1% (95% CI 89.3%, 96.8%), with 11 COVID-19 cases in the vaccine group and 185 COVID-19 cases in the placebo group, the agency said, consistent with results obtained from an earlier interim analysis.

On Dec. 10, the first adolescent participants were dosed in Moderna’s phase II study of patients ages 12 to 18.

At the Dec. 17 FDA advisory committee meeting, 21 voting participants expressed clarity about the urgency of adding a second vaccine to the U.S.'s emergency arsenal amid the ongoing pandemic, which as of Dec. 17 had killed nearly 310,000 people in the U.S. and sickened millions more.