Different COVID-19 Vaccines
The best COVID-19 vaccine is the first one that is available to you. Do not wait for a specific brand. All currently authorized and recommended COVID-19 vaccines:
are effective, and
reduce your risk of severe illness.
CDC does not recommend one vaccine over another.
People 16 years and older
2 Shots Given 3 weeks (21 days apart)
People 18 years and older
2 Shots Given 28 days apart
Johnson & Johnson Janssen
Persons 18 years and older
1 If you have had a severe allergic reaction (anaphylaxis) or an immediate allergic reaction to any ingredient in the vaccine you are scheduled to receive, you should not get that vaccine. If you have been instructed not to get one type of COVID-19 vaccine, you may still be able to get another type. Learn more information for people with allergies.
2 You should get your second shot as close to the recommended 3-week or 4-week interval as possible. However, your second shot may be given up to 6 weeks (42 days) after the first dose, if necessary.
Currently, three vaccines are authorized and recommended in the United States to prevent COVID-19:
- Understanding How COVID-19 Vaccines Work
Learn how the body fights infection and how COVID-19 vaccines protect people by producing immunity. Also see the different types of COVID-19 vaccines that currently are available or are undergoing large-scale (Phase 3) clinical trials in the United States.
- COVID-19 mRNA Vaccines
Information about mRNA vaccines generally and COVID-19 vaccines that use this new technology specifically.
- Viral Vector COVID-19 Vaccines
Information about viral vector vaccines generally and COVID-19 vaccines that use this new technology specifically.
Vaccines in Phase 3 Clinical Trials
As of February 27, 2021, large-scale (Phase 3) clinical trials are in progress or being planned for two COVID-19 vaccines in the United States:
AstraZeneca COVID-19 vaccine
Novavax COVID-19 vaccine
Learn more about U.S. COVID-19 vaccine clinical trials, including vaccines in earlier stages of development, by visiting clinicaltrials.govexternal icon.
This page will be updated as additional information is available.Content provided and maintained by the US Centers for Disease Control and Prevention (CDC). Please see our system usage guidelines and disclaimer.