ATLANTA, GA-Studies show that COVID-19 vaccines are effective at keeping you from getting COVID-19. Experts also think that getting a COVID-19 vaccine may help keep you from getting seriously ill even if you do get COVID-19. But while COVID-19 vaccines can keep you from getting sick, scientists are still learning how well vaccines prevent you from spreading the virus that causes COVID-19 to others. So even after vaccination, we need to continue using all the tools available to help stop this pandemic as we learn more about how COVID-19 vaccines work in real-world conditions. Although the vaccine supply is currently limited, the federal government is working toward making vaccines widely available.
Because COVID-19 is a new disease with new vaccines, information is rapidly emerging about how vaccines can help us stop the pandemic. CDC will update this page with more information about what we know—and what we don’t know—as it becomes available. Learn more facts about COVID-19 vaccines.
Currently, two vaccines are authorized and recommended to prevent COVID-19:
Pfizer-BioNTech COVID-19 vaccine
Moderna COVID-19 vaccine
Vaccine Types
Understanding How COVID-19 Vaccines Work
This web page explains how the body fights infection and how COVID-19 vaccines protect people by producing immunity. It also describes the different types of COVID-19 vaccines that currently are available or are undergoing large-scale (Phase 3) clinical trials in the United States.
Understanding COVID-19 mRNA Vaccines
This web page provides information about mRNA vaccines generally and about COVID-19 vaccines that use this new technology specifically.
Understanding Viral Vector COVID-19 Vaccines
This web page provides information about viral vector vaccines generally and about COVID-19 vaccines that use this new technology specifically.
Vaccines in Phase 3 Clinical Trials
As of December 28, 2020, large-scale (Phase 3) clinical trials are in progress or being planned for three COVID-19 vaccines in the United States:
- AstraZeneca’s COVID-19 vaccine
- Janssen’s COVID-19 vaccine
- Novavax’s COVID-19 vaccine
Help stop the pandemic by getting vaccinated
What we know
illustrations of vaccine, person wearing a mask, hand washing, and social distancing
Studies show that COVID-19 vaccines are effective at keeping you from getting COVID-19. Experts also think that getting a COVID-19 vaccine may help keep you from getting seriously ill even if you do get COVID-19.
COVID-19 vaccination is an important tool to help us get back to normal. Learn more about the benefits of getting vaccinated.
COVID-19 vaccines teach our immune systems how to recognize and fight the virus that causes COVID-19. It typically takes a few weeks after vaccination for the body to build protection (immunity) against the virus that causes COVID-19. That means it is possible a person could still get COVID-19 just after vaccination. This is because the vaccine has not had enough time to provide protection.
There are steps you can take to protect yourself until you can get vaccinated. Even after you get vaccinated it’s important to continue using all the tools available to help stop this pandemic as we learn more about how COVID-19 vaccines work in real-world conditions. Even after vaccination, take steps to protect yourself and others from COVID-19.
What we do not know
Although COVID-19 vaccines are effective at keeping you from getting sick, scientists are still learning how well vaccines prevent you from spreading the virus that causes COVID-19 to others, even if you do not get sick.
If you are vaccinated against COVID-19, you may still be exposed to the virus that causes COVID-19. After exposure, people can be infected with or “carry” the virus that causes COVID-19 but not feel sick or have any symptoms. Experts call this “asymptomatic infection.”
For this reason, even after vaccination, we need to continue using all the tools available to help stop this pandemic as we learn more about how COVID-19 vaccines work in real-world conditions.
You may have side effects after vaccination, but these are normal
After COVID-19 vaccination, you may have some side effects. These are normal signs that your body is building protection. The side effects from COVID-19 vaccination, such as chills or tiredness, may affect your ability to do daily activities, and they should go away in a few days. Learn more about what to expect after getting vaccinated.
Media Release/Centers for Disease Control and Prevention
