FDA on Wednesday released its analysis of the Covid-19 vaccine developed by Johnson & Johnson (J&J), saying the vaccine was safe and effective—paving the way for the agency to provide an emergency use authorization (EUA) in the coming days.

4 takeaways on the Johnson & Johnson, Novavax vaccine trial results

FDA says J&J's vaccine is safe and effective

For the analysis, FDA analyzed a 45,000-person, international clinical trial conducted by J&J. It found that, overall, the vaccine was 66.9% effective at preventing moderate to severe Covid-19 among patients who had been vaccinated at least two weeks previously. There were no Covid-19 hospitalizations or fatalities among patients who had been vaccinated at least 28 days previously.

When broken down by region, the study found that, among patients who had been vaccinated at least 28 days previously:

• In the United States, the vaccine had an 72% efficacy rate against moderate to severe Covid-19 cases and an 85.9% efficacy rate against severe cases of Covid-19;
• In South Africa, where the B.1.351 variant is driving most Covid-19 cases, the vaccine had a 64% efficacy rate against moderate to severe Covid-19 cases and 81.7% efficacy rate against severe Covid-19 cases; and
• In Brazil, where the P.1 variant is prevalent, the vaccine had a 68.1% efficacy rate against moderate to severe cases of Covid-19 and an 87.6% efficacy rate against severe cases.

According to the study, the vaccine provided similar levels of protection across Black, Hispanic, and white participants, as well as across various age groups.

In total, there were seven deaths during the trial, all of which occurred in the group who received a placebo.

According to the New York Times, there were no reports of severe allergic reactions, such as anaphylaxis, among those who received the vaccine, and reported side effects appeared to be milder than those linked to the vaccines produced by Pfizer/BioNTech and Moderna.

Specifically, the most commonly reported side effects were injection site pain, which nearly half of participants reported, followed by headache, fatigue, and muscle pain.

Ultimately, FDA said the vaccine has a "favorable safety profile" with "no specific safety concerns identified that would preclude issuance of an EUA."

What experts think

According to the Times, J&J's vaccine has certain logistical advantages over Pfizer/BioNTech's and Moderna's vaccines, the two vaccines authorized for use in the United States. Specifically, J&J's vaccine can be stored at normal refrigeration temperatures for at least three months, and it only requires one dose.

"With a J&J vaccine, we'll be able to accelerate the vaccine rollout for our country and the world," Dan Barouch, a virologist at Beth Israel Deaconess Medical Center, said.

Experts especially praised the vaccine's effect on reducing severe or fatal cases of Covid-19.

"What you care about is hospitalizations and deaths," Ashish Jha, dean of the Brown University School of Health, said. "Johnson & Johnson appears to be just as good as Moderna and Pfizer at preventing those."

"We know this vaccine prevents 85% of the severe disease. … It was 100% effective in preventing hospitalization and deaths, and that's really what's important," Nancy Bennett, a professor of medicine and public health sciences at the University of Rochester School of Medicine and Dentistry, said. "Those facts are the most important thing to recognize."

What's next?

On Friday, an external group of scientists is scheduled to meet to decide on whether J&J's vaccine should be recommended for an EUA by FDA. Following that meeting, FDA could issue an authorization as soon as this weekend, Axios reports.

However, the vaccine's initial supply may be low, the Times reports. The U.S. government has a deal for 100 million doses of the vaccine by the end of June. However, Richard Nettles—VP of U.S. medical affairs at Janssen Pharmaceuticals, J&J's drug development arm—told lawmakers Tuesday that about four million doses of the vaccine will be ready to ship once FDA issues an EUA, far fewer than the original 12 million promised by the end of February, according to the Times.

And White House officials on Tuesday told state governors on a call that as of next week, pending the vaccine's authorization, only about two million doses will be available. Jeff Zients, White House coronavirus coordinator, added J&J will not have a "big inventory" of doses ready to ship immediately, although Nettles noted that the company will have 20 million doses ready to ship by the end of March (Axios, 2/24; Zimmer et. al., New York Times, 2/24; Johnson/McGinley, Washington Post, 2/24; Hensley, NPR, 2/24).