– Looking to get the facts about the new COVID-19 vaccines? Here’s what you need to know about the different vaccines and the benefits of getting vaccinated.

Vaccines to prevent the coronavirus disease 2019 (COVID-19) are perhaps the best hope for ending the pandemic. But as the U.S. Food and Drug Administration (FDA) begins authorizing emergency use of COVID-19 vaccines, you likely have questions. Find out about the benefits of the COVID-19 vaccines, how they work, the possible side effects and the importance of continuing to take infection prevention steps.

What are the benefits of getting a COVID-19 vaccine?

COVID-19 can cause severe medical complications and lead to death in some people. There is no way to know how COVID-19 will affect you. If you get COVID-19, you could spread the disease to family, friends and others around you.

Getting a COVID-19 vaccine can help protect you by creating an antibody response in your body without your having to become sick with COVID-19.

A COVID-19 vaccine might prevent you from getting COVID-19. Or, if you get COVID-19, the vaccine might keep you from becoming seriously ill or from developing serious complications.

Getting vaccinated also might help protect people around you from COVID-19, particularly people at increased risk of severe illness from COVID-19.

What COVID-19 vaccines have been approved and how do they work?

Currently, several COVID-19 vaccines are in clinical trials. The FDA will review the results of these trials before approving COVID-19 vaccines for use. But because there is an urgent need for COVID-19 vaccines and the FDA‘s vaccine approval process can take months to years, the FDA will first be giving emergency use authorization to COVID-19 vaccines based on less data than is normally required. The data must show that the vaccines are safe and effective before the FDA can give emergency use authorization.

Pfizer/BioNTech vaccine

The FDA has given emergency use authorization to the Pfizer/BioNTech COVID-19 vaccine. Data has shown that the vaccine starts working soon after the first dose and has an efficacy rate of 95% seven days after the second dose. This means that about 95% of people who get the vaccine are protected from becoming seriously ill with the virus. This vaccine is for people age 16 and older. It requires two injections given 21 days apart.

Moderna vaccine

Moderna has applied for FDA emergency use authorization of its COVID-19 vaccine. Data has shown that the vaccine has an efficacy rate of 94.1%. This vaccine requires two injections given 28 days apart.

Both the Pfizer/BioNTech and the Moderna COVID-19 vaccines use messenger RNA (mRNA). Coronaviruses have a spike-like structure on their surface called an S protein. COVID-19 mRNA vaccines give cells instructions for how to make a harmless piece of an S protein. After vaccination, cells begin making the protein pieces and displaying them on cell surfaces. Your immune system will recognize that the protein doesn’t belong there and begin building an immune response and making antibodies.

Can a COVID-19 vaccine give you COVID-19?

No. The COVID-19 vaccines currently being developed in the U.S. don’t use the live virus that causes COVID-19.

Keep in mind that it will take a few weeks for your body to build immunity after getting a COVID-19 vaccination. As a result, it’s possible that you could become infected with the virus that causes COVID-19 just before or after being vaccinated.

What are the possible side effects of a COVID-19 vaccine?

A COVID-19 vaccine can cause mild side effects, including:

  • Pain, redness or swelling where the shot was given
  • Fever
  • Fatigue
  • Headache
  • Muscle pain
  • Chills
  • Joint pain

Most reactions happen with the first few days after vaccination and last no more than three days. If you experience side effects after getting a COVID-19 vaccine, it doesn’t mean that you have COVID-19. Take time to rest and recover. If you develop a fever, stay home. However, it’s not necessary to get a COVID-19 test or quarantine.

If you have a reaction that prevents you from being able to eat, sleep or work, contact your doctor. Also, contact your doctor if you have a reaction that lasts longer than three days.

Signs of an allergic reaction include hives, swelling of the face and throat, difficulty breathing, a fast heartbeat, dizziness, and weakness. If you have any of these signs, seek care immediately.

How are the COVID-19 vaccines being distributed?

Due to limited supplies, not everyone will be able to get a COVID-19 vaccine right away.

The Advisory Committee on Immunization Practices (ACIP) is a U.S. federal advisory group made up of medical and public health experts. The ACIP has recommended that in the first phase of vaccination in the U.S., COVID-19 vaccines should be given to health care personnel and adult residents of long-term care facilities. Other groups under consideration for early COVID-19 vaccination include workers in essential and critical industries, adults at high risk of severe COVID-19 due to underlying medical conditions, and adults age 65 and older.

Is there anyone who should not get a COVID-19 vaccine?

The COVID-19 vaccine is not being offered to pregnant women. This is because researchers don’t know enough about how COVID-19 vaccination can affect children, pregnant women or their babies. There is also no data on the safety of COVID-19 vaccines for breastfeeding women.

The Pfizer/BioNTech vaccine is not available to children under age 16.

COVID-19 vaccination also might not be recommended for people with certain health conditions. Talk to your doctor if you have questions about getting the vaccine.

Also, if you have a history of allergic reactions, talk to your doctor before getting the vaccine. You might need to be observed for a short time after getting the vaccine.

Should I get the COVID-19 vaccine even if I’ve already had COVID-19?

Getting COVID-19 might offer some natural protection or immunity from reinfection with the virus that causes COVID-19. But it’s not clear how long this protection lasts. Because reinfection is possible and COVID-19 can cause severe medical complications, it might be recommended that people who have already had COVID-19 get a COVID-19 vaccine.

Can I stop taking safety precautions after getting a COVID-19 vaccine?

Experts want to learn more about the protection that a COVID-19 vaccine provides and how long immunity lasts before changing safety recommendations. Factors such as how many people get vaccinated and how the virus is spreading in communities will also affect these recommendations.

In the meantime, the Centers for Disease Control and Prevention recommends following these precautions for avoiding infection with the COVID-19 virus:

  • Avoid close contact. This means avoiding close contact (within about 6 feet, or 2 meters) with anyone who is sick or has symptoms. Also, keep distance between yourself and others. This is especially important if you have a higher risk of serious illness.
  • Wear cloth face coverings in public places. Cloth face coverings offer extra protection in places such as the grocery store, where it’s difficult to avoid close contact with others. Surgical masks may be used if available. N95 respirators should be reserved for health care providers.
  • Practice good hygiene. Wash your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitizer that contains at least 60% alcohol. Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue. Avoid touching your eyes, nose and mouth. Avoid sharing dishes, glasses, bedding and other household items if you’re sick. Clean and disinfect high-touch surfaces daily.
  • Stay home if you’re sick. Stay home from work, school and public areas if you’re sick, unless you’re going to get medical care. Avoid public transportation, taxis and ride-sharing if you’re sick.

If you have a chronic medical condition and may have a higher risk of serious illness, check with your doctor about other ways to protect yourself.


  1. Coronavirus disease 2019 (COVID-19): How to protect yourself & others. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html. Accessed Dec. 4, 2020.
  2. Amanat F, et al. SARS-CoV-2 vaccines: Status report. Immunity. 2020; doi:10.1016/j.immuni.2020.03.007.
  3. AskMayoExpert. COVID-19: Vaccination. Mayo Clinic; 2020.
  4. How CDC is making COVID-19 recommendations. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations-process.html. Accessed Dec. 8, 2020.
  5. Vaccines and related biological products advisory committee meeting. U.S. Food and Drug Administration. https://www.fda.gov/media/144245/download. Accessed Dec. 9, 2020.
  6. Office of Patient Education. COVID-19 vaccine. Mayo Clinic; 2020.
  7. Benefits of getting a COVID-19 vaccine. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/vaccine-benefits.html. Accessed Dec. 8, 2020.
  8. Facts about COVID-19 vaccines. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/vaccine-benefits/facts.html. Accessed Dec. 8, 2020.
  9. Understanding mRNA COVID-19 vaccines. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html. Accessed Dec. 8, 2020.
  10. Frequently asked questions about COVID-19 vaccination. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/faq.html. Accessed Dec. 8, 2020.
  11. COVID-19 frequently asked questions. U.S. Food and Drug Administration. https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/covid-19-frequently-asked-questions. Accessed Dec. 9, 2020.
  12. Moderna announces primary efficacy analysis in phase 3 COVE study for its COVID-19 vaccine candidate and filing today with the U.S. FDA for emergency use authorization. Moderna. https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-primary-efficacy-analysis-phase-3-cove-study. Accessed Dec. 9, 2020.
  13. Facts about COVID-19 vaccines. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/vaccine-benefits/facts.html. Accessed Dec. 9, 2020.
  14. Interim considerations for COVID-19 vaccination of healthcare personnel and long-term care facility residents. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19/clinical-considerations.html. Accessed Dec. 10, 2020.
  15. Oliver SE, et al. The Advisory Committee on Immunization Practices’ interim recommendation for use of Pfizer-BioNTech COVID-19 vaccine — United States, December 2020. Morbidity and Mortality Weekly Report. 2020; doi: http://dx.doi.org/10.15585/mmwr.mm6950e2.
  16. DeSimone DC (expert opinion). Mayo Clinic. Dec. 14, 2020.
  17. Mbaeyi S. Use of Pfizer-BioNTech COVID-19 vaccine: Clinical considerations. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2020-12/slides-12-12/COVID-03-Mbaeyi.pdf. Accessed Dec. 14, 2020.

Go to Original – mayoclinic.org