The US Food and Drug Administration authorized Johnson & Johnson's Covid-19 vaccine Saturday. It is the first single dose Covid-19 vaccine available in the US, and is one that "checks nearly all the boxes."
With more than 28.5 million confirmed Covid-19 cases and over 511,000 reported deaths in the US since the start of the pandemic, and while the demand for vaccine still far exceeds supply, these vaccines can't come soon enough.
"A third safe and effective vaccine is very welcome news," Andy Slavitt, the White House's senior for Covid Response, tweeted on Friday.
The vaccine, made by Janssen, J&J's vaccine arm, is safe and effective, and it's considered flexible. It's a single dose, and it doesn't require special storage.
The vaccine is authorized for people ages 18 and older.
"We need a vaccine that can be quickly mass produced," Dr. Greg Poland, head of the Mayo Clinic's Vaccine Research Group, said Friday. "We'd want to see a reasonable duration of efficacy and protection.
"The Janssen vaccine candidate checks nearly all the boxes."
The vaccine was tested in more than 44,000 people in the US, South Africa and Latin America. Globally, it was 66.1% effective against moderate to severe/critical Covid-19 at least four weeks after vaccination, according to an FDA analysis. In the US, it is considered 72% effective, and offered 86% protection against severe forms of the disease.
"One dose will keep you out of the hospital, keep you out of the intensive care unit, and keep you out of the morgue," Dr. Paul Offit, a vaccine adviser to the FDA, told CNN's Wolf Blitzer on Friday.
The vaccine comes with few side effects, most of which are mild, including pain at the injection site, headache, fatigue and muscle pain.
Overall, non-fatal serious adverse events were infrequent, according to the FDA's analysis, and there were no reported cases of anaphylaxis following vaccination in the trial. There have been a small number of severe allergic reactions with the Moderna and Pfizer/BioNTech vaccines. For example, in the first week of the Pfizer vaccine rollout, there were only 29 cases out of 1.9 million doses administered, according to the US Centers for Disease Control and Prevention.
More research is needed, but the FDA analysis also hinted that the J&J vaccine may help prevent asymptomatic infections.
A January study from the CDC showed that most coronavirus cases are spread by people without symptoms. If a vaccine prevented asymptomatic infection, it might help reduce opportunities to transmit the disease -- not just keep the vaccinated from getting sick.
With so much positive data, an independent group of advisers voted unanimously on Friday to recommend the emergency use authorization of the J&J vaccine.
"I think it's a relatively easy call. It clearly gets way over the bar, and it's nice to have a single-dose vaccine," Dr. Eric Rubin, a member of the committee who is also the editor in chief of The New England Journal of Medicine and a professor at the Harvard T.H. Chan School of Public Health, said after the vote.
There is some concern that because the public has heard that the shot is only 72% protective in the US, and the Pfizer and Moderna Covid-19 vaccines are about 95% protective, some will think this is a "second class" vaccine, but the experts say those numbers are highly misleading.
"It's difficult to make an apples-to-apples comparison between vaccines authorized based on data collected before new variants are believed to have been in widespread circulation," said Sarah Christopher, the policy advocacy director at the National Women's Health Network. Christopher spoke during the public comment section of the FDA's advisory meeting on Friday.
The Pfizer and Moderna Covid-19 vaccines were tested earlier in the pandemic when there were fewer known variants. FDA research found that the majority of the cases that happened during the South African part of the J&J trial came from a newer and possibly more contagious variant.
Public health experts say people should take whatever shot is first available to them.
"If I had a J&J vaccine available today and a Moderna vaccine available tomorrow, I would be happy to take the J&J today. I don't feel like I would need to wait. They are all terrific vaccines for the things that we care about," Dr. Ashish Jha, dean of the Brown University School of Public Health, told a House Ways and Means Health Subcommittee hearing Friday.
Experts have said variants may fuel a surge of cases in the spring in the US, and say that's one reason why it's important to get as many people vaccinated as quickly as possible.
"We'll be seeing how much of an impact the variants have and how best these vaccines can address them, whether it will be booster doses, or other vaccines," said Dr. Aditya Gaur, a co-lead investigator on the J&J trial at St. Jude in Memphis. "But I think one could not have asked for better from this first round of vaccine development from a standpoint of how quickly it has happened and how quickly it has started to roll out around the world."
On Sunday, the CDC's Advisory Committee on Immunization Practices, known as ACIP, will meet to set the guidelines for who should get the vaccine. Their vote is scheduled for 3 p.m. ET.
From there, the much needed vaccine could start rolling out to vaccine centers around the country.
While the initial supply is limited -- the company says it only has about 4 million doses of its vaccine ready to ship "immediately" -- it should have 20 million ready by the end of March.
The advancement of the Johnson & Johnson coronavirus vaccine is "really good news for the world," Dr. Francis Collins, director of the National Institutes of Health, told CNN's Wolf Blitzer on Friday. Even with cases in the US declining recently, the pandemic is far from over. "The best way to get done is with this vaccine being added to the others."