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 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, mRNA-1273, 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 ages 18 and older while the Pfizer-Biontech vaccine is for those ages 16 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 Hahn.

On the heels of that authorization, the European Commission (EC) exercised an option to buy another 80 million doses of mRNA-1273 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 the vaccine is approved by the EMA.

The EMA said it has been in a continuous dialogue with Moderna to ensure questions that arose during its evaluation of the vaccine were addressed. The company last week submitted the last outstanding data package needed for the EMA’s assessment, with data specific to the manufacturing of the vaccine for the EU market.

The EMA’s Committee for Medicinal Products for Human Use (CHMP) has scheduled an extraordinary meeting Jan. 6 for completing its assessment of the vaccine. Within days of the CHMP recommending a marketing authorization, the EC is expected to fast track its authorization decision.

Moderna’s vaccine also is still under rolling review in Canada, which was one of the first countries to authorize the Pfizer-Biontech vaccine. Acknowledging the FDA’s EUA for mRNA-1273, Health Canada said it began reviewing the Moderna vaccine Oct. 12 and is still awaiting more information and data.

While it can’t provide a definite timeline for completing its review, Health Canada said it expects to complete the review “in the coming weeks.” It added that it’s working closely with international regulators, including the FDA, to share information and data on COVID-19 vaccines under review.

Evidence and distribution

Moderna’s mRNA-1273 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-blind and placebo-controlled trial of the candidate in about 30,400 participants were offered as support for the EUA in the U.S. 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. That’s 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.

The first doses of the Moderna vaccine were expected to be delivered to states Dec. 21. At a media briefing last week, Health and Human Services Secretary Alex Azar said the government already had allocated nearly 5.9 million doses of the Moderna vaccine to be distributed this week, along with another 2 million doses of the Pfizer-Biontech vaccine.

The distribution of the Moderna vaccine comes exactly a week after the Pfizer-Biontech vaccine began to be delivered throughout the U.S. Despite all the planning and field exercises to prepare for the nationwide distribution, there were some glitches last week, with some states receiving 25% to 40% fewer vaccine doses than originally anticipated, according to Rep. Rosa DeLauro (D-Conn.).

Over the weekend, Gen. Gustave Perna, chief operating officer for Operation Warp Speed (OWS), took responsibility for the difference in the forecast doses and the number actually delivered. He said that when approving the forecasts, he had underestimated the time needed to approve doses for distribution.

The distribution ramp up for the Pfizer-Biontech vaccine also raised a few unexpected questions. Perna noted that the temperature for a few trays of the vaccine being delivered to California and Alabama were 12 degrees colder than the -80 specified. The trays were returned to Pfizer and replaced.

OWS is working with the FDA, the CDC and Pfizer to determine if the vaccine is still safe at the colder temperature, Perna said.

Another question arose over the quantity in the vial, which is labeled as containing enough vaccine for five doses. Many vials contained enough for six doses. Since two doses will be required 21 days apart, providers were concerned about giving more people the first dose if the vials produced for the second dose don’t contain as much.