The US is one step closer to having a third Covid-19 vaccine and it can't come soon enough.
With people clamoring for a shot, it was welcome news that the US Food and Drug Administration's analysis Johnson & Johnson's trial data showed its vaccine is safe and effective.
Here's what that could mean for you.
How soon will the J&J vaccine be available?
It could be as soon as early next week.
The vaccine still has a few steps to go before the FDA gives emergency use authorization.
On Friday, the FDA's Vaccines and Related Biological Products Advisory Committee holds a public meeting. This independent group of experts determines if the vaccine works and if it's safe. It will then make a recommendation to the FDA. The FDA usually follows its advice. The FDA could sign off on the vaccine as early as Friday or Saturday.
On Sunday afternoon, the US Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices, known as ACIP, is scheduled to meet and set guidelines for who should get the vaccine. Their vote is scheduled for 3pm.
From there, the vaccine could start rolling out of the J&J facility to vaccine centers around the country.
But don't expect those vaccine waiting lists to be gone any time soon.
The supply is limited. The company says it only has 4 million doses of its vaccine ready to ship "immediately." It should have 20 million ready by the end of March.
Where will people get this one?
That depends on where you live.
The Biden administration said Tuesday that about 2 million doses will go to the states after the vaccine is authorized.
Since states don't have a lot of details yet, a lot of plans are up in the air. Until they know details like how many and when they will get these vaccines, it's hard to plan. They also want to know who the vaccine may work for best.
Arkansas said it won't have details to share until it knows more about the characteristics of the vaccine.
Colorado said regardless of the details it hopes to make the J&J vaccine available at mass vaccination sites.
New York City plans a new initiative to expand access to seniors.
Since the J&J vaccine only requires one shot and doesn't need special refrigeration, medical personnel will be able to bring the vaccine to homebound adults who cannot get to vaccination center.
The White House said Monday that the vaccines that aren't sent to states in this initial rollout will go to pharmacies and community health centers.
Will I be able to choose the kind of vaccine I get?
"My advice to all my patients and to all my friends will be to get the first vaccine you can get. That's what matters the most -- to get protected," said Dr. Jeff Carson, Provost at Rutgers Biomedical and Health Sciences of Rutgers University in New Jersey.
Colorado plans to offer a choice at its larger mass vaccination sites, according to Brig. Gen. Scott Sherman, director of the state's unified coordination center vaccine task force. But that may not be true for all places where people get a vaccine.
Right now, with the Moderna and Pfizer vaccines, some sites have been offering whatever vaccine they have the most of that day. The supply changes from week to week.
Plus, it's not clear right now if the J&J shot will be better for one group or the other. The ACIP committee will help make that determination Sunday and from there the states will make decisions based on those guidelines.
How long do I have to wait for protection for this shot vs. other shots?
With any vaccine it takes your body a few weeks to build up immunity. Protection doesn't happen right away.
With the J&J vaccine it looks like protection against moderate/severe disease starts about two weeks after you get vaccinated. By four weeks after the shot, data from the clinical trial showed there were no hospitalizations or deaths.
Remember, this is a single dose shot, so there is no waiting around to get a second to develop full protection. US trials of the J&J shot showed it provides 72% of protection against moderate to severe disease after one month.
Recent studies show you get some good level of protection with the first dose of the Moderna and Pfizer vaccines, but you don't get full protection until about two weeks after your second dose. With the Moderna vaccine, the CDC says you should get your second shot four weeks after the first one. With the Pfizer shot it is three weeks. It takes about two weeks to develop the optimal level of protection after the second shot. The shots prevent Covid-19 disease 95% of the time.
How safe is this one?
The FDA analysis said the J&J vaccine has a "favorable safety profile."
The side effects were mostly mild. The most common were pain at the injection site, headache, fatigue and muscle pain. Some people had hives. Most of these side effects went away in one or two days.
There appeared to be more incidents related to blood clotting and ringing in the ears among those people who got the vaccine in the trial, compared to those who didn't, but the FDA notes that "data at this time are insufficient to determine a causal relationship between these events and the vaccine."
There were no reports of serious allergic reactions with this one.
With the Moderna and Pfizer Covid-19 vaccines, there have been a handful of severe allergic reactions, but this has been an extremely rare outcome. 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.