Enlarge / This unassuming building in Massachusetts has taken on remarkable significance in recent weeks. (credit: JOSEPH PREZIOSO / Getty Images )

Earlier this week, the FDA released documents that summarized the data on a second SARS-CoV-2 vaccine candidate, this one from a company called Moderna. That document was the background for a meeting of the FDA's Vaccines and Related Biological Products Advisory Committee, which would consider whether the benefits of the vaccine outweigh its potential risks. That question is one of the key considerations for the agency as it decides whether to grant an emergency use authorization similar to the one it gave the Pfizer/BioNTech vaccine .

After an all-day meeting that frequently focused on other topics, the committee was near unanimous: 20 votes for approval, none against, and one abstention.

Emergency use authorizations have a number of requirements once a health emergency hsa been declared. There must be no alternatives that have achieved full FDA approval, there must be reasons to think that the treatment will be effective, and its benefits are considered likely to outweigh its risks. It's that final question—the risk vs. benefit balance—that the advisory committee was called to address.