COVID-19 Vaccine

The key to effectively managing coronavirus is vaccination.

Currently, there are two vaccines authorized for use in the United States to prevent coronavirus disease 2019 (COVID-19). Other vaccines are being developed and are in various stages of the development and testing process.

Photo of COVID-19 vaccine administration


Since it was discovered in the U.S. in early 2020, Coronavirus has infected more than 21 million Americans and killed more than 380,000. The introduction of vaccines to fight the COVID-19 opens up the path to managing the deadly disease.

By choosing to be vaccinated, you can protect not only yourself and your family but your community as well.

When can I get the vaccine?

The vaccine is strongly encouraged for all eligible adults, and it is being distributed in a phased approach designated by the state of Missouri. Learn more about vaccine availability.

State of Missouri COVID-19 Vaccine Availability Phases
The COVID-19 vaccine will be available in phased approach. Learn more.


As of Jan. 18, the state of Missouri has approved vaccinating people in Phase 1A and Tier 1 and Tier 2 of Phase 1B. Please note: Our ability to vaccinate depends on our supply of vaccine. Click below to sign up for notification of vaccine availability.

COVID-19 Vaccine Survey

How does the vaccine work?

The first two vaccines to earn authorization — those developed by Pfizer and its German partner, BioNTech, and Moderna — use messenger RNA (mRNA) to instruct the body to build the Coronavirus’ signature spike protein. The body then produces antibodies to combat the Coronavirus when it enters the body.

The Pfizer-BioNTech vaccine requires two doses given 21 days apart. The Moderna vaccine requires two doses given 28 days apart. Data from the clinical trials found the Pfizer-BioNTech vaccine to be 95% effective after two doses and the Moderna vaccine 94.1% effective, meaning they prevented people who got the vaccine from getting COVID-19.

Facts about COVID-19 mRNA vaccines:

  • They cannot give you COVID-19.
    • mRNA vaccines do not use the live virus that causes COVID-19.
  • They do not affect or interact with your DNA in any way.
    • mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept.
    • The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.

Learn more about mRNA vaccines.

Are the vaccines safe?

The vaccines have passed the same rigorous Food and Drug Administration (FDA) standards as other vaccines. They were tested in large clinical trials — made up of tens of thousands of adults of different ages, races, ethnicities and medical conditions — to ensure they meet safety standards.

  • The FDA carefully reviews all safety data from clinical trials and authorizes emergency vaccine use only when the expected benefits outweigh potential risks.
  • The Advisory Committee on Immunization Practices (ACIP) reviews all safety data before recommending any COVID-19 vaccine for use.
  • FDA and Centers for Disease Control and Prevention will continue to monitor the safety of COVID-19 vaccines to ensure even very rare side effects are identified.

You cannot get COVID-19 from the vaccines. Some participants in the trials did report side effects similar to mild symptoms of Coronavirus infection, including muscle pain, chills and a headache. Serious reactions were rare.

What if I’ve already had COVID-19?

If you have already had COVID-19, there is evidence that you can still benefit from the vaccine. At this time, experts do not know how long someone is protected from getting sick again after recovering from COVID-19. The immunity someone gains from having an infection, called natural immunity, varies from person to person. Some early evidence suggests natural immunity may not last very long.

See below on timing of when you should consider vaccination.

More Frequently Asked Questions

Q: If I’ve had COVID-19, how long do I need to wait to get vaccinated?

A: The Advisory Committee on Immunization Practices recommends that people wait until they’ve recovered and have completed the isolation period. For most people, that is 10 days after symptom onset and at least 24 hours without fever. For people with no symptoms, isolation can be discontinued 10 days after the first positive test.

Because reinfection is uncommon within 90 days of infection and vaccine supply currently is limited, people with documented acute infection are OK to delay the vaccine for 90 days if they choose.

If you are infected between your first and second doses, you should consult with your health care provider and consider getting the second dose after completing the isolation period. You should not wait 90 days because it’s unknown how that long of a delay would impact the vaccine’s effectiveness.

Q: If I received an antibody treatment or convalescent plasma can I get the vaccine?

A: Anyone who received monoclonal antibody or convalescent plasma treatment for COVID-19 should wait 90 days before getting vaccinated. This precautionary delay is recommended because it’s unclear if the treatment would interfere with the vaccine-induced immune response.

Q: If I get the vaccine, do I still have to wear a mask?

A: Yes. Masking, handwashing and physical distancing remain necessary until enough of the population is immune and spread is unlikely. The best protection we can offer each other right now is to continue to follow masking and distancing guidelines when at work and in our personal lives, when appropriate. Evidence will be continuously reviewed, and practices continuously modified in regard to public health interventions.

Q: How long will I have immunity after getting a vaccine, and will it last longer than immunity from having the disease?

A: Because this virus is new, we don’t know how long immunity lasts — either for infection or vaccination.

Q: Should I wait after getting my flu shot to receive a COVID-19 vaccine?

A: Consistent with CDC guidelines, we recommend the Pfizer vaccine be spaced at least 14 days from any other vaccine, including the flu vaccine.

Q: What are common reactions to the vaccine?

A: Most reactions are mild to moderate and are similar to side effects seen with other immunizations. These can include fever, soreness at the injection site, or even a temporary flu- like feeling with muscle aches, headache or fatigue.

Q: What if I have a reaction to the vaccine?

A: Some people might develop temporary flu-like symptoms, including fever, shortly after the second dose. This reaction is not an infection or sickness but is part of the immune system’s reaction to “seeing” the proteins from the vaccine.

State of Missouri Vaccine Information