The Food and Drug Administration issued an emergency use authorization Friday for the COVID-19 vaccine developed by Moderna and the National Institutes of Health, paving the way for another 6 million vaccines to be shipped by early next week. 

“With the availability of two vaccines now for the prevention of COVID-19, the FDA has taken another crucial step in the fight against this global pandemic that is causing vast numbers of hospitalizations and deaths in the United States each day,” FDA Commissioner Stephen Hahn said in a statement.

The authorization for the Moderna/NIH vaccine comes a week after the FDA granted emergency use authorization for a vaccine developed by Pfizer and BioNTech that began to be distributed in the U.S. this week.

Shipments have been projected to begin Tuesday night.

Like the Pfizer vaccine, the Moderna vaccine requires two doses. For this vaccine, the doses should be spaced 28 days apart.

Data from clinical trials show the vaccine is 94.5 percent effective 14 days after two doses have been administered. Potential side effects raised during a Thursday meeting of outside advisers to the FDA included Bell’s palsy, a temporary paralysis of facial muscles; the potential for allergic reactions, which has also happened in a few cases after health care workers received the Pfizer vaccine; and cases of facial swelling in two trial participants who had dermal fillers.

The FDA sped up the process in a few ways. The agency has been working with developers since the spring and early summer to expedite their applications and ensure they meet the agency’s requirements, which were spelled out in two guidance documents released in June and October.

It was “all on hands on deck” at the FDA’s Center for Biologics Evaluation and Research, which worked “night and day” on the vaccine applications, Hahn said at a press conference last week. 

The agency won’t do onsite inspections of manufacturing quality, which typically take a few months, but will instead scrutinize reports from the manufacturers. 

FDA is collecting a median of two months of safety data, which is less than a typical approval would get. But the agency’s independent advisers with the Vaccines and Related Biological Products Advisory Committee have pointed out that in the history of vaccines, the vast majority of side effects are detected within two months of a shot. Both Pfizer/BioNTech and Moderna/NIH will submit their vaccines for full approval in the coming months. 

The VRBPAC voted, 20-0 with one panelist abstaining, on Thursday evening to recommend the Moderna shots. 

Moderna’s application for an emergency use authorization appeared to clear the agency’s hurdles by showing broad efficacy and two months of safety data in documents released earlier this week in advance of the VRBPAC meeting. But the agency’s career scientists had not yet completed their independent number crunching to verify the data. 

The FDA and the Centers for Disease Control and Prevention are monitoring potential side effects, investigating around five cases in different states of severe allergic reactions to the Pfizer vaccine and preparing for the potential of similar reactions from the Moderna vaccine. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, told reporters on a Friday night call that the two vaccines have one shared component associated with allergic reactions. That ingredient is polyethylene glycol. It’s not certain, though, that this component is causing the reactions.

Marks also said studies will be undertaken to study the effects of vaccines on pregnant women. Officials are still discussing the design of those studies, but some are getting underway.

Marks said there would be no difference between the two vaccines as to which vaccine pregnant women should receive.

“Either one of these vaccines is a reasonable choice after a woman has a conversation with her health care provider about the potential benefits of the vaccine versus its risk and the potential risk of COVID-19 and its adverse effects on pregnancy,” Marks told reporters.

Moderna’s massive clinical trial enrolled 7,000 people over the age of 65, plus 7,000 people with co-morbid conditions that can worsen the impact of COVID-19 and about 9,000 people from Black or Latino populations. 

Moderna’s vaccine will be able to reach more remote areas than the Pfizer/BioNTech vaccine, supply chain experts say, both because of its more durable storage capability and because of its containers. The Trump administration’s COVID-19 initiative, Operation Warp Speed, said earlier this week that while Pfizer would ship its vaccine to 636 places across the country, the Moderna vaccine would land at 3,285 locations.

Moderna received funds from Operation Warp Speed for the development and the manufacturing of its vaccine. Sen. Steve Daines, R-Mont., who pushed for $10 billion for vaccine development and manufacturing to be included in an earlier pandemic relief law, said that funding was crucial to begin ending the pandemic. Moderna CEO Stephane Bancel praised Daines for his work, “which enabled BARDA and Operation Warp Speed to accelerate our progress to this point,” he said.

Daines, a chemical engineer who previously worked with FDA-regulated products, told CQ Roll Call in an interview that in March he’d had to sell colleagues on the investment in the Biomedical Advanced Research and Development Authority to both develop and manufacture vaccines simultaneously. Including it in that package helped make vaccines available some six months sooner than they may have been otherwise as the administration stood up Operation Warp Speed, he said.

“Here we’re in the final throes of putting together another approximately trillion-dollar package to deal with relief for the pandemic, and yet a $10 billion investment back in March, once we fully execute this vaccine plan, will likely stop the pandemic,” he said. “That’s how you get back to normal again.”