Key Things to Know About COVID-19 Vaccines

Key things to know about COVID-19

The CDC recently released an updated fact sheet providing key information related to COVID-19 Vaccines. The fact sheet provides updates on recent policies, vaccination status, definitions, and safety information. As part of the most recent OSHA ETS, this information is required to be provided by employers. You may download a copy of the original key fact sheet by clicking on the image to the right, or you may read the contents  directly below.

What You Need to Know

from the virus that causes COVID-19, including known variants currently circulating (e.g., Delta variant).

pandemic. However, people should wear a mask indoors in public if they are in an area of substantial or high transmission.

  • If you received a Pfizer-BioNTech (ages 12 and older) or Moderna (ages 18 and older)

mRNA COVID-19 vaccine primary series and have a moderately or severely compromised immune system, you should receive an additional primary dose of the same mRNA COVID-19 vaccine at least 28 days after the second dose.

  • Everyone ages 16 years and older can get a booster shot. Pfizer-BioNTech or

Moderna (mRNA COVID-19 vaccines) are preferred in most situations. Although mRNA vaccines are preferred, J&J/Janssen COVID-19 vaccine may be considered in some situations.

  • Unlike many medications, COVID-19 vaccine dosage does not vary by patient weight but by age on the day of
  • People can get a COVID-19 vaccine and other vaccines, including flu vaccine, at the same

Availability of Vaccines

COVID-19 vaccines are widely accessible in the United States. Everyone ages 5 years and older should get a COVID-19 vaccination as soon as possible. COVID-19 vaccines are available for everyone at no cost, regardless of their immigration or health insurance status

Many doctors’ offices, retail pharmacies, hospitals, and clinics offer COVID-19 vaccinations. Visit to find locations that are offering vaccines to everyone ages 5 years and older. Parents can check with their child’s healthcare provider, their local pharmacy, and health department about whether they offer COVID-19 vaccination. Learn more about how to find a COVID-19 vaccine.


COVID-19 vaccines are effective at protecting people from COVID-19 and help keep adults and children from getting seriously sick. COVID-19 vaccines can reduce the risk of people spreading the virus that causes COVID-19. Getting everyone ages 5 years and older vaccinated can help the entire family, including siblings who are not eligible for vaccination and family members who may be at risk of getting very sick if they are infected.

Adults and children 5 years and older who are fully vaccinated can resume activities that they did before the pandemic. Learn more about what people can do when they have been fully vaccinated.


Studies show that COVID-19 vaccines are effective, especially at keeping adults and children from getting seriously ill even if they do get COVID-19. 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 2 weeks after vaccination for the body to build (immunity) against the virus that causes COVID-19.

People are considered fully vaccinated 2 weeks after their second dose of the Pfizer- BioNTech or Moderna COVID-19 vaccines, or 2 weeks after the single-dose Johnson & Johnson’s Janssen COVID-19 vaccine. To receive the most protection, people should receive

of a COVID-19 vaccine. Learn more about who is recommended to get an additional primary dose or a booster dose.

People can sometimes get COVID-19 after being fully vaccinated. However, this only happens in a small proportion of people, even with the Delta variant. When these infections occur among vaccinated people, they tend to be mild.

Learn more about the effectiveness of COVID-19 vaccines.

COVID-19 vaccines are safe and effective. Vaccines cannot give you COVID-19. You may have side effects after vaccination. These are normal and should go away within a few days.

COVID-19 vaccines are safe and effective. Millions of people in the United States have received COVID-19 vaccines. COVID-19 vaccines have undergone and continue to undergo the most intensive safety monitoring in U.S. history, which includes studies about adolescents and children. This monitoring includes using both established and new safety monitoring systems

  to make sure that COVID-19 vaccines are safe.

Before recommending COVID-19 vaccination for children, scientists conducted clinical trials. The FDA gave the Pfizer- BioNTech COVID-19 vaccine emergency authorization to use in children ages 5 years through 15 years old and full approval to use in people ages 16 years and older. Learn more about the process of developing, authorizing and approving COVID-19 vaccines.

COVID-19 vaccines cannot give you COVID-19. There is no evidence that COVID-19 vaccines cause fertility problems. Read more to bust myths and learn the facts about COVID-19 vaccines.

CDC has developed a tool, v-safe, to help monitor how people are feeling after getting COVID-19 vaccines. V-safe is a free, easy-to-use, and confidential smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after vaccination. Parents and caregivers can enroll themselves and their children ages 5 years and older in v- safe and report how they are feeling after they have been vaccinated for COVID-19. Learn how the federal government is using and other systems to monitor and ensure the safety of COVID-19 vaccines.

While COVID-19 vaccines were developed rapidly, all steps have been taken to ensure their safety and effectiveness.

Population Immunity

Population immunity makes it hard for a disease to spread from person to person. It even protects those who cannot be vaccinated, like newborns or people who are allergic to a vaccine. The percentage of people who need to have protection to achieve population immunity varies by disease.

We are still learning how many people need to be vaccinated against COVID-19 before the population can be considered protected.

As we know more, CDC will continue to update our recommendations for both vaccinated and unvaccinated people.

Vaccines and Variants

  • FDA-authorized COVID-19 vaccines help protect against COVID-19 and known variants.
  • These vaccines are effective at keeping adults and children 5 years and older from getting COVID-19, getting very sick, and
  • To maximize protection from the virus that causes COVID-19 and prevent possibly spreading it to others, you should wear a mask indoors in public if you are in an area of substantial or high transmission even if you are fully
  • We don’t know how effective the vaccines will be against new variants that may