A coronavirus disease 2019 (COVID-19) vaccine candidate developed by Moderna was deemed highly effective by the FDA in a filing released Tuesday, which could clear the way for a second COVID-19 vaccine to gain emergency use authorization (EUA) in the United States.

The FDA’s Vaccines and Related Biological Products Advisory Committee is expected to review the safety and efficacy data package on December 17, which could lead to an EUA being issued soon thereafter. On December 11, the FDA approved an EUA application for BNT162b2, jointly developed by Pfizer and BioNTech, which began administration to the first wave of recipients on Monday.

Moderna’s COVID-19 vaccine candidate, mRNA-1273, showed 94.5% efficacy in preventing COVID-19, according to preliminary results from the ongoing phase 3 COVE trial. In data submitted to an independent data and safety monitoring board (DSMB) overseeing the trial, the interim review showed that the vaccine is safe and effective at preventing symptomatic COVID-19 in adults, according to a press release from the National Institutes of Health.

“This is a pivotal moment in the development of our COVID-19 vaccine candidate. Since early January, we have chased this virus with the intent to protect as many people around the world as possible. All along, we have known that each day matters. This positive interim analysis from our phase 3 study has given us the first clinical validation that our vaccine can prevent COVID-19 disease, including severe disease,” said Stéphane Bancel, chief executive officer of Moderna, in a November press release.

The primary efficacy analysis, conducted on 196 cases, confirmed the 94.1% efficacy observed in the first interim analysis. This efficacy was consistent across age, race and ethnicity, and gender demographics. The cases included 33 older adults and 42 participants who identified themselves as being from diverse communities (29 Hispanic or Latinx, 6 Black, 4 Asian Americans, and 3 multiracial participants).

The primary endpoint of the COVE study is based on the analysis of COVID-19 cases confirmed and adjudicated starting 2 weeks after the second dose of the Moderna vaccine. In the primary analysis, 185 cases of COVID-19 were observed in the placebo group compared with 11 cases observed in the group who received the vaccine.

A secondary endpoint analyzed severe cases of COVID-19 and included 30 severe cases. All 30 occurred in the placebo group and none in the vaccinated group. To date, there has been 1 COVID-19-related death in the study, which occurred in the placebo group.

The interim analysis included 95 cases of symptomatic COVID-19 among volunteers. The DSMB found that the vaccine was safe and well-tolerated with a statistically significant vaccine efficacy rate. Ninety of the cases occurred in the placebo group and 5 occurred in the vaccinated group. Among the 95 total cases, there were 11 cases of severe COVID-19, all of which occurred in the placebo group.

Data released by the FDA on Tuesday suggest that Moderna’s vaccine candidate may also prevent the spread of COVID-19, with asymptomatic infection reduced by 63% following administration of the first dose; however, the FDA may require 2 doses of the vaccine for maximum protection.