After a full day of discussions, the Food and Drug Administration (FDA) advisory committee voted unanimously to recommend authorization of mRNA-1273, Moderna's (NASDAQ:MRNA) coronavirus vaccine. There was one abstention among the 21 votes by outside experts on the panel.

The FDA doesn't have to follow the recommendation of the advisory committee, but considering how positive the agency's review of the vaccine was, it seems highly likely regulators will issue an emergency use authorization (EUA) for mRNA-1273. Based on last week's schedule for Pfizer and BioNTech's coronavirus vaccine, BNT162b2, the FDA could issue the EUA tomorrow.

Doctor giving an injection into a child's arm

Image source: Getty Images.

While it's clear mRNA-1273 protects people from developing COVID-19, there are still some unanswered questions, including how much protection a single dose of the vaccine provides. There were fewer cases of COVID-19 between the first and second doses in participants who received the vaccine, compared to the group who received placebo, suggesting that there may be some protection from a single dose. But since almost all participants received two doses, it's impossible to tell if a single dose would offer long-term protection.

There's also a question of whether the mRNA-1273 is able to prevent transmission of the virus or if it simply reduces the likelihood of developing COVID-19. The committee also questioned whether the people who got mRNA-1273 but still developed COVID-19 were infected with a strain of the virus that the vaccine doesn't protect against. Unfortunately, Moderna doesn't have the answers to those questions yet.

Moderna will need to collect additional data before applying for a full approval for mRNA-1273, but an EUA authorization would allow the biotech to sell the vaccine for as long as the pandemic is deemed an emergency.

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