At first, Pfizer-BioNTech’s vaccine appeared to require ultra-cold storage, but the FDA approved the company's claim that the vaccine did not actually need it.
The Johnson & Johnson vaccine was found to be 72 per cent effective in a US trial, but less so in South Africa and South America, with variants threatening the efficacy of vaccines.
FDA briefing documents also stated that the Johnson & Johnson vaccine was effective in reducing the risk of Covid-19, preventing asymptomatic infections and avoiding medical intervention.
No patient in the vaccine trial was admitted to hospital or died from Covid-19.
Bahrain was the first country to issue emergency approval of the vaccine.
The panel held a day-long meeting to review information, discuss concerns and address questions about the vaccine before it held its vote.
The FDA is not bound to follow what the panel recommends, but it often does.
Its commissioner could issue the emergency-use approval within the next few days.
President Joe Biden's administration has ordered 100 million doses from Johnson & Johnson.
The company says it is ready to send out 20 million in March, after it receives full approval, and projects it can send the remaining 80 million by June.
The US is dealing with the worst coronavirus outbreak in the world, with the highest death toll and the most recorded cases.
It passed 500,000 fatalities on Tuesday.
The vaccination programme is well under way in the US. The Centres for Disease Control and Prevention report more than 14 per cent of Americans have received one vaccine dose, while 6.8 per cent have been fully vaccinated.
Cases, deaths and hospital admissions had been on the decline from the worst surge in December and January until this week, when the downward trend appears to have stalled.
There is growing concern that with new highly transmissible variants spreading, there may be another small surge of cases.
The expectation is that the UK variant will become the dominant US coronavirus strain in March, while health authorities are monitoring ones detected in California and New York.
The rise of new variants is further emphasising the need for widespread vaccination.
Centres for Disease Control Director Rochelle Walensky said at the White House Covid-19 task force briefing Friday: “We may be done with the virus but clearly the virus is not done with us.”