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8 common questions about COVID-19 vaccines

Many aspects of the COVID-19 pandemic are unprecedented. One of those is the ongoing effort to quickly develop a safe and effective vaccine against the virus that causes COVID-19.

Here are answers to a few questions you may have about these potential vaccines.

Q. How many vaccines are in development?

A. Multiple vaccines are being worked on in the U.S. Four have already begun phase 3 clinical trials. Phase 3 clinical trials involve tens of thousands of people, and they're typically the final stage of the vaccine trial process.

Q. Why are so many vaccines being developed at once?

A. The vaccines work in different ways. Some are based on using dead viruses to stimulate immunity. (This is the same method used for the flu shot and many other vaccines.) Others use just a part of the virus, like the spike protein from its surface. And still others are based on newer methods using the virus's genetic material—either on its own or inserted into another harmless virus. Exploring different approaches gives a better chance of finding a safe and effective vaccine soon.

Q. When will a vaccine be ready?

A. It's hard to say. Once clinical trials are complete, the U.S. Food and Drug Administration (FDA) has to review the trial data. Then it decides whether to approve the vaccine. If approved, the vaccine would then be made and distributed across the country. Some experts believe that may take six months to a year after FDA approval.

Q. Who will get the vaccine first?

A. An expert advisory committee has been looking at who should get vaccines first if the supply is limited early on. Groups that may get priority could include:

  • Healthcare workers.
  • Workers in essential and critical industries.
  • People at high risk for severe COVID-19 due to underlying medical conditions.
  • People 65 and older.

Q. How will we know a vaccine is safe?

A. A vaccine must be shown to be safe and effective before it can be offered to the public. That's what the clinical trial process is for. Phase 1 trials test a vaccine in a small number of people. Phase 2 trials test a vaccine in several hundred people. Phase 3 trials involve thousands of people who are given either the vaccine or a placebo. All of these trials assess a vaccine's safety and how well it works.

The FDA will only approve a vaccine if it determines that the benefits outweigh the risks. And the FDA continues to monitor vaccines for safety after they're approved. That includes inspecting the production process and tracking reports of side effects.

Q. What does it mean when a vaccine trial is paused?

A. A vaccine trial may be paused for safety when one or more participants have what's called an adverse event. That's usually an unexplained illness. Researchers temporarily pause the trial so they can look into whether the person's illness was random or related to the vaccine being studied. These pauses are a normal part of the clinical trial process. They mean that the system is working the way it should.

Q. How much will a vaccine cost?

A. The government has said vaccines will be provided either free or at low cost. If there is a cost to getting vaccinated, most health plans will cover it. So there should be no cost to the person getting the vaccine.

Q. When I get a vaccine, will I be able to stop social distancing and wearing a mask?

A. No. A vaccine is just one safety measure we can use to help stop the pandemic. But no vaccine is 100% effective. People will still need to wear masks and stay 6 feet away from others after getting the vaccine. That will need to continue until health experts are sure the vaccine provides long-term protection and until a large enough portion of the public is vaccinated to stop the virus from spreading so widely.

In the meantime, learn more about how to help stop the spread in our Coronavirus health topic center.

Reviewed 11/3/2020

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