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8 common questions about COVID-19 vaccines

A healthcare worker in a mask and face shield touches the shoulder of a masked patient.

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. Five are in progress or being planned for Phase 3 clinical trials. Phase 3 clinical trials involve tens of thousands of people. 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. But if the first vaccines submitted to the U.S. Food and Drug Administration (FDA) are approved, some doses can start shipping out almost immediately. That means some people may be able to be vaccinated before the end of the year. But it could take six months or more for a vaccine to be distributed to everyone who needs it.

Q. Who will get the vaccine first?

A. In early December, the Advisory Committee on Immunization Practices recommended that the following groups should be offered the vaccine first:

  • Healthcare workers.
  • Residents of long-term care facilities.

Later groups may include people 65 and older and people at high risk for severe COVID-19 due to underlying medical conditions.

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 12/4/2020

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