The Food and Drug Administration released a detailed analysis Tuesday morning of the COVID-19 vaccine from drugmaker Moderna that supports the authorization of the company's vaccine for emergency use.

The FDA's briefing document along with one from Moderna were posted two days before a group of experts will convene to advise the agency on whether to grant the vaccine emergency authorization for use, or EUA, during the pandemic.

The agency's analysis finds the vaccine has a "favorable safety profile" and that there are "no specific safety concerns identified that would preclude issuance of an EUA." Serious reactions were rare. Side effects are common, however, with a majority of study volunteers experiencing pain at the site of injection, fatigue and headaches.

The agency's analysis also affirms the effectiveness of the vaccine. It is 94% overall, assessed at least two weeks after the second dose of vaccine, in the final analysis. An interim analysis put it at 95%. The vaccine shots are given 28 days apart.

The vaccine is less effective in older people, the FDA analysis finds. For people ages 18 to less than 65, the effectiveness is 96%, compared with 86% for people 65 and older.

On Thursday, the Vaccines and Related Biological Products Advisory Committee, an advisory group, will discuss the vaccine in an open public meeting.

Last Thursday, Dec. 10, the same committee voted 17-4, with one abstention, in favor of emergency authorization of the Pfizer vaccine for use during the pandemic. The Pfizer vaccine, developed in partnership with German drugmaker BioNTech, was given the OK for use for people 16 and older.

The FDA will ask the experts to assess whether the available scientific evidence supports the proposed emergency use of the Moderna vaccine. The FDA will also ask the experts to weigh in on what studies should be done by the companies to further characterize the safety and effectiveness of the vaccine after it is available under an EUA.

Immunizations with the Pfizer vaccine began Monday. Distribution of the vaccine is complicated by its need to be kept extremely cold: minus 76 degrees Fahrenheit or colder.

For shipping and storage, Moderna's vaccine needs to be frozen, too, but at minus 4 degrees Fahrenheit — more like a regular home freezer. Once the vaccine is thawed for use, it can be kept at 36 to 46 degrees Fahrenheit, the temperature of a typical home fridge, for up to 30 days.

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