Skip to content

Coronavirus Vaccine: When Will We Have One, Who Gets It and Will It Work?

As the pandemic rolls on, researchers race to find answers

image of a vial labeled coronavirus vaccine

Manjurul/Getty Images

En español | Getting past the “new normal” and back to the way things were before the coronavirus pandemic hit hinges on the development and widespread availability of a vaccine. Without one, some public health experts predict, current tactics aimed to suppress the virus and the damage it causes — think school closures and stay-at-home orders — could continue intermittently into 2022.

The good news: More than 100 biotech companies and academic institutions around the world are racing to find a vaccine, according to the Milken Institute’s COVID-19 Treatment and Vaccine Tracker. Here’s what you need to know.

What, exactly, is a vaccine?

A vaccine is something that helps a person build up immunity to an infectious disease. It works by intentionally introducing the body to an inactive form of a disease-causing germ, or something similar to it. This then stimulates the immune system’s production of antibodies, the proteins that help to protect the person from a future infection if they ever come across the real germ.

Think of it like a workout for your immune system: You’re “sending it to the gym and preparing it to be able to do something when it encounters the real thing in the future,” says Tony Moody, M.D., associate professor of pediatrics and immunology at Duke University School of Medicine and a principal investigator at the Duke Human Vaccine Institute.

For the latest coronavirus news and advice go to

“Essentially, what a vaccine is doing is teaching the immune system how to handle something before you actually encounter the real thing. So that hopefully, when you do encounter the real thing, you’re able to deal with it quickly and get rid of it.”

In the case of the new coronavirus, a vaccine would make a person resistant to an infection from the virus and the illness it causes — COVID-19 — or, at the very least, make it so that a person who becomes infected has “a shorter course [of disease] or not as many complications,” Moody says.

Who is working on a coronavirus vaccine?

Everyone — government scientists, biotech companies, university researchers — is involved in the effort to develop a coronavirus vaccine. It’s a crowded field with more than 100 different projects underway, but Kathleen Neuzil, M.D., professor in vaccinology and director of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, says that’s a good problem to have.

“Many more vaccines are going to fail than succeed, so you want a lot of shots on goal,” Neuzil says.

Another reason it’s advantageous to have so many institutions working on prevention efforts is that a pandemic, by definition, means this is a global rather than a national issue to resolve. “We are going to have a demand for a vaccine for over 7 billion people,” Neuzil says.

If more than one works, that’s OK. Think of the flu vaccine, Neuzil says: There are multiple formulations on the market, including the injectable high-dose vaccine and the nasal spray vaccine, for example. If more than one coronavirus vaccine proves safe and effective, it might be that one works better in older adults while another is better for children.

“And as I said, we really need every person on earth, theoretically, to be able to receive this vaccine,” Neuzil says. “So, to me, [having more than one option] is a positive, because we need so much.”

Will the coronavirus vaccine be made of the live virus?

A handful of existing vaccines — including polio, chicken pox and the measles, mumps and rubella shot (MMR) — contain a weakened version of the live virus that causes the disease. Because it’s the closest thing to a natural infection, so-called live attenuated vaccines “are good teachers for the immune system,” the Centers for Disease Control and Prevention (CDC) explains.

Few research teams are taking this approach with the coronavirus vaccine, however, since “it takes a lot of time to be sure [the virus used in the vaccine] is weak enough that it doesn’t cause disease,” Neuzil says. And in a pandemic, time is of the essence.

Instead, scientists are looking at different ways to introduce a piece of the virus to the body — whether it’s a protein from the virus or a genetic code that the body can use to make its own protein to stimulate an immune response. Some are also studying the possibility of introducing the coronavirus by way of a vector, where a gene for a protein of the coronavirus, for example, is inserted into a harmless form of another virus and delivered to the cells. The advantage of this approach, Neuzil says, is that the vector-carrying vaccine “looks more like the real virus than perhaps just a piece of the protein does.”

“These are just different ways that we’re trying to get at the same goal: We’re trying to have the body make its own immune response to the virus,” Neuzil says. “Since this is such a new disease, we don’t really know what’s going to work the best for [the coronavirus], so we’re trying a number of different approaches.”

When will a vaccine be available?

The answer to the question on everyone’s mind — when will a vaccine be available? — varies depending on whom you ask. Anthony Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID) and a key member of the White House coronavirus task force, has said he is “cautiously optimistic” a vaccine will be available by the end of 2020 or early 2021. In a June 2 interview with the Journal of the American Medical Association (JAMA), Fauci explained the government is going to “start manufacturing doses of the vaccines way before we even know that the vaccine works,” so that if one does prove safe and effective in clinical trials, it can quickly be deployed to the public. The federal government’s Operation Warp Speed project has so far invested billions in this accelerated approach.

The third phase of a clinical trial testing a vaccine candidate from the biotech company Moderna is expected to begin in July. Data from an early-stage trial show the Moderna vaccine candidate produced an immune response in all 45 trial participants, ages 18 to 55 years old, The third phase will test the vaccine in a much larger population. Several other trials testing potential vaccines are also underway.

Does it usually take this long to develop a vaccine?

Though the timelines projected for the coronavirus vaccine may seem long and “frustratingly inefficient,” Duke’s Moody says, in reality this process is moving at record speed. Vaccine development typically takes 10 to 15 years, according to a vaccine history resource created by the College of Physicians of Philadelphia. The fastest vaccine created thus far was for mumps; that process took four years.

Traditionally, researchers need time to prove a vaccine is safe and effective in a series of months-long clinical trials before it is mass-produced and distributed throughout the world.

“And those processes take time because, you know, you’ve got to give people the full injection series, you have to follow them for long enough to see if there’s an effect, and it’s got to be done in a setting where you can actually tell if people are protected or not,” Moody says.

The key, experts say, is finding the balance between speed and safety. In the case of the new coronavirus, some parts of the vaccine process can be accelerated, says Amesh Adalja, an infectious disease physician and senior scholar at the Johns Hopkins University Center for Health Security. “But there is a lot of testing that needs to be done if you’re going to make a vaccine that’s going to vaccinate the entire world,” he adds. Even a small adverse effect, when amplified on a global scale, can hurt a lot of people.

The Food and Drug Administration (FDA) in June released a set of guidelines for drugmakers, detailing requirements for vaccine approval. Coronavirus vaccine candidates need to be at least 50 percent effective compared to a placebo in clinical trials, the agency says. And safety considerations “should be no different than for other preventive vaccines for infectious diseases.”

“I think it’s really important for people to understand that the response to this pathogen has been faster than any other pathogen in history,” Moody says. “The fact that you had a virus that was first reported in China in December, and by March we were already talking about setting up a phase 1 trial … I think the speed of the response, both by the medical community and by everyone else, is actually pretty astonishing.”

What if scientists don’t come up with a vaccine that works?

That’s also a possibility. And that’s why it’s important to pursue therapeutics for COVID-19, as well, Moody says.

“If we had sort of the Tamiflu equivalent for coronavirus where you could be exposed and take Tamiflu and, you know, be protected, or you could get early disease and it could attenuate the disease or shorten the course, that would be great,” Moody says of the antiviral treatment for influenza. “There’s a lot of work being done there. And I think all of that work needs to proceed as well.”

The FDA on May 1 issued an emergency use authorization for Gilead Sciences’ antiviral drug remdesivir as a treatment option for people who are hospitalized with COVID-19. The news came days after the National Institutes of Health (NIH) announced preliminary results from an international clinical trial that showed that patients severely ill with COVID-19 who received remdesivir recovered faster than similar patients who received a placebo. The steroid dexamethasone has also been shown in preliminary studies to help with recovery from a coronavirus infection. Still, there is no official FDA-approved treatment for COVID-19.

Once a vaccine is developed, will high-risk populations get it first?

“That’s an interesting and also a somewhat complicated question,” Moody says. The early phases of clinical trials are usually conducted in young, healthy people, and the population at highest risk for severe illness from a coronavirus infection includes adults 65 and older and people with chronic health conditions. So if trials are fast-tracked or certain phases are skipped, it could be risky to vaccinate the high-risk population without adequate testing first.

“If we get to a point where you have a vaccine that looks like it’s effective but has a limited supply, then my expectation is it will probably end up going first to people who are on the front lines,” Moody says. “So health care workers, EMS, police, fire — all the people who are in situations where they’ve got to interact with the public.”

A major issue to consider, however, is that the definition of frontline workers extends beyond health care workers and emergency responders. Grocery workers, delivery personnel and public transportation employees are all essential workers who are also at high risk of exposure, Moody points out. “And how do you prioritize that? That’s going to be a complicated discussion,” he says. “I don’t know how well our society has done at having those conversations, but I think they are conversations we’re going to have to have.”

dynamic a logo mark for a a r p

Save 25% when you join AARP and enroll in Automatic Renewal for first year. Get instant access to discounts, programs, services, and the information you need to benefit every area of your life.

Will the coronavirus vaccine be annual, like the flu shot?

It’s hard to say at this point. So far, the new coronavirus has not shown signs of “rapid genetic change,” like influenza viruses, Neuzil says. That’s why a new flu vaccine is needed every year. If that continues to be the case, a coronavirus vaccine likely wouldn’t need to be administered on an annual basis. At the same time, Neuzil says she would be “surprised if a vaccine for a respiratory virus conferred lifelong immunity.” So it will probably fall somewhere in between.

“I usually remind people that we’ve only known about this virus not quite five months yet,” Neuzil says. “We are learning a lot.”

This article, originally published May 1, has been updated to reflect new information.

Join the Discussion

0 | Add Yours

Please leave your comment below.

You must be logged in to leave a comment.