The Food and Drug Administration appeared on track Tuesday to authorize Moderna's COVID-19 vaccine this week in the same process used to evaluate and issue emergency authorization for Pfizer's COVID-19 vaccine.
FDA scientists and experts said there was strong evidence the Moderna vaccine is 94.5% effective at preventing COVID-19 cases at least 14 days after vaccination and that there were no significant safety concerns.
The COVID-19 vaccines from Pfizer and Moderna use similar technology and both require two doses, but they cannot be combined. Because the supply of both is limited which vaccine people receive will likely be determined by which is available in the area they live at the time of vaccination.
One significant difference is that the Moderna vaccine has not been studied in children so it will only be authorized for people 18 and older at this time. Moderna's clinical trial also did not include pregnant women and people with a compromised immune system.
The most common side effects reported from the Moderna vaccine were pain at the site of injection, fatigue, headache, muscle pain, join pain, and fever.
A group of independent experts that advises the FDA on vaccines will meet Thursday and vote on whether the benefits of authorizing the Moderna vaccine outweigh any risks, essentially recommending it for emergency authorization.
FDA Commissioner Stephen Hahn will then decide whether to sign off on emergency authorization. Advisors for the Centers for Disease Control and Prevention will then meet to finalize recommendations on who should receive the Moderna vaccine, which would need to be approved by CDC Director Robert Redfield.