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COVID-19 vaccines

Vaccines for COVID-19; COVID - 19 vaccinations; COVID - 19 shots; Vaccinations for COVID - 19; COVID - 19 immunizations; COVID - 19 prevention - vaccines; mRNA vaccine - COVID; COVID-19 vaccine booster shots; Booster shots for COVID-19

COVID-19 vaccines are used to prepare the body's immune system to protect against COVID-19. These vaccines are a vital tool to help stop the COVID-19 pandemic.

Everyone ages 5 and older should get a free COVID-19 vaccination. This includes people who are pregnant and those planning to become pregnant. You should get a COVID-19 vaccine even if you have already had COVID-19.


COVID-19 vaccine



COVID-19 vaccines protect people from getting COVID-19 and from getting more severe symptoms if they get COVID-19. These vaccines "teach" your body how to defend against the SARS-CoV-2 virus, which causes COVID-19.

COVID-19 vaccines have been shown to do a very good job of:


The preferred COVID-19 vaccines approved in the United States are called mRNA vaccines. They work differently from many other vaccines.

The COVID-19 mRNA vaccine is given as an injection (shot) in the arm in 2 doses.

People who have a weak immune system (immunocompromised) should get an additional dose at least 28 days after their second shot of either the Pfizer-BioNTech or Moderna mRNA vaccine. This includes people receiving certain types of cancer treatment and people taking medicines that suppress the immune system. Ask your doctor if you are not sure. Getting a third dose will improve the response to the vaccine in people with weak immune systems.

Children ages 5 to 17 can get the Pfizer-BioNTech mRNA vaccine. This is the only vaccine available to this age group at this time. The Pfizer-BioNTech vaccine given to children and teens has the same active ingredients as the vaccine given to adults.


The Johnson and Johnson's Janssen (J&J/Janssen) COVID-19 vaccine is a viral vector vaccine. It is given as one shot. It has been approved for use in the United States in some cases:

It takes time for your immune system to start protecting you after receiving the vaccine. You are considered fully vaccinated:


COVID-19 vaccines:

To get up-to-date accurate information about COVID-19 vaccines, go to the Centers for Disease Control and Prevention (CDC) website:


While COVID-19 vaccines will not make you sick, they may cause certain side effects and flu-like symptoms. This is normal. These symptoms are a sign that your body is making antibodies against the virus. Common side effects include:

Side effects from the shot may affect your ability to do daily activities, but they will go away in a few days. Even if you have side effects, you should get the second shot. Any side effects from the vaccine are far less dangerous than the potential for serious illness or death from COVID-19.


There are several ways you can look for vaccination providers near you.

Learn what to expect when you get your COVID-19 vaccine.


The safety of vaccines is the top priority, and COVID-19 vaccines have passed rigorous safety standards before approval. Millions of people have received the vaccine, and no long-term side effects have been reported. They continue to be closely monitored to ensure they are safe and effective.

There have been reports of some people who have had an allergic reaction to the current vaccines. So it is important to follow certain precautions:

If you have had an allergic reaction, even if not severe, to other vaccines or injectable therapies, you should ask your doctor if you should get a COVID-19 vaccine. Your doctor will help you decide if it is safe to get vaccinated.

CDC recommends that people may still get vaccinated if they have a history of:

To learn more about COVID-19 vaccine safety, go to the CDC website:


Over time, COVID-19 vaccines appear to become less protective against the virus. Getting a booster dose helps provide additional protection against COVID-19. As a result, a booster shot is now recommended for all people age 18 and older.

If you received the Pfizer-BioNTech or Moderna mRNA vaccine, you can get a booster dose 5 months after receiving your second dose of the initial vaccine.

If you received the J&J/Janssen vaccine, you can get a booster dose 2 months after receiving your initial vaccine.

It is recommended to get an mRNA vaccine (Pfizer-BioNTech or Moderna) for your booster dose, regardless of which vaccine you first received. People ages 12 to 17 can only get the Pfizer-BioNTech vaccine as the booster dose.

The CDC has further information about COVID-19 vaccine booster shots.


The CDC has recommendations for what it is safe to do once you are fully vaccinated.

We are still learning how well vaccines help prevent COVID-19 from spreading and how long the protection they provide lasts. Until more is known, using vaccines, masks, and taking other steps to help protect yourself and others is the best way to stay safe and healthy.


Centers for Disease Control and Prevention website. Benefits of getting a COVID-19 vaccine. Updated February 25, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. COVID-19 vaccines for children and teens. Updated January 11, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. COVID-19 vaccines for moderately to severely immunocompromised people. Updated February 17, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. COVID-19 vaccines for people who would like to have a baby. Updated March 3, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. Different COVID-19 vaccines. Updated January 21, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States. Updated February 22, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. Myths and facts about COVID-19 vaccines. Updated December 15, 2021. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. Allergic reactions after COVID-19 vaccination. Updated February 3, 2022. Accessed March 13, 2022.

Centers for Disease Control and Prevention website. COVID-19 vaccine booster shots. Updated February 2, 2022. Accessed March 13, 2022.


Review Date: 3/13/2022  

Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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