COVID-19 Vaccine: What You Need to Know

The COVID-19 vaccine is very good at preventing serious illness, hospitalization and death. Because the virus that causes COVID-19 continues to change, vaccines are updated to help fight the disease. It is important to check the Centers for Disease Control and Prevention (CDC) COVID-19 vaccine information for the latest details. (Posted 11/22/23)

What is the COVID-19 vaccine?

The COVID-19 vaccine lessens the severity of COVID-19 by teaching the immune system to recognize and fight the virus that causes the disease.

For fall/winter 2023–2024, the updated COVID-19 vaccine is based on the XBB.1.5 variant. The updated vaccine is made by Pfizer-BioNTech, Moderna and Novavax. This season, only one shot of the vaccine is needed for most people, and there are no boosters. (People who are immunocompromised or ages 6 months to 4 years may need more than one 2023–2024 vaccine.)

How is the 2023–2024 COVID-19 vaccine different from previous COVID-19 vaccines?


The 2023–2024 COVID-19 vaccine targets XBB.1.5, a subvariant of Omicron. While none of the variants currently circulating are exact matches to the vaccine, they are all closely related to the XBB.1.5 strain. Studies show that the updated vaccine is effective against the variants currently causing the majority of COVID-19 cases in the U.S.

Who should get a COVID-19 vaccine?

Because the 2023–2024 vaccine is effective for recent strains of COVID-19, it is recommended that everyone stay up to date with this vaccine. Previous vaccines or boosters were not developed to target the more recent strains. For 2023–2024, the CDC recommends:

  • Everyone age 5 and older receive one shot of the updated vaccine.
  • Children ages 6 months to 4 years may need more than one shot to be up to date.
  • People who are moderately or severely immunocompromised may need more than one shot.

You can review the full recommendations on the CDC’s Stay Up to Date with COVID-19 Vaccines webpage. Be sure to talk to your primary care doctor or pediatrician if you are unsure about vaccine recommendations.

What are the side effects of the COVID-19 vaccine?

Side effects vary and may last one to three days. Common side effects are:

  • Soreness at the injection site
  • Fatigue
  • Headache
  • Body aches
  • Fever

COVID-19 Vaccine and Pregnancy

COVID-19 vaccines approved by the Food and Drug Administration (FDA) are safe and recommended for people who are pregnant or lactating, as well as for those r intending to become pregnant.

People who are pregnant or were recently pregnant are at a greater risk for severe COVID-19. Having a severe case of COVID-19 while pregnant is linked to a higher risk of pre-term birth and stillbirth and might increase the risk of other pregnancy complications.

What should parents know about the COVID-19 vaccine and children?

The CDC recommends the 2023–2024 vaccine for adolescents and teenagers ages 12 and older, and for children ages 6 months through 11 years.

  • Children age 5 and older need one shot of the updated vaccine.
  • Children ages 6 months to 4 years may need more than one shot to be up to date.

Children are less likely to become seriously ill from COVID-19 than adults, although serious illness can happen. Speak with your pediatrician if you have questions about having your child vaccinated.

If I recently had COVID-19, do I need a 2023–2024 vaccine?

If you recently had COVID-19, the CDC recommends waiting about three months before getting this updated vaccine. If you encounter the virus again, having the updated vaccine will:

  • Lessen your risk of severe disease that could require hospitalization
  • Reduce the chance that you infect someone else with COVID-19
  • Help keep you protected from currently circulating COVID-19 variants

How long should I wait to get this vaccine if I recently had an earlier version of a COVID-19 vaccine or booster?

People age 5 years and older should wait at least two months after getting the last dose of any COVID-19 vaccine before receiving the 2023–2024 vaccine, according to CDC guidance.

Is natural immunity better than a vaccine?

Natural immunity is the antibody protection your body creates against a germ once you’ve been infected with it. Natural immunity to the virus that causes COVID-19 is no better than vaccine-acquired immunity, and it comes with far greater risks. Studies show that natural immunity to the virus weakens over time and does so faster than immunity provided by COVID-19 vaccination.

Do I need a COVID-19 booster?

The 2023–2024 vaccine is a one-shot vaccine for most people, and there is no booster this season. (People who are immunocompromised or ages 6 months to 4 years may need more than one 2023–2024 vaccine.)

The FDA calls this an updated vaccine (not a “booster” like previous shots) because it builds a new immune response to variants that are currently circulating. This change reflects the current approach of treating COVID-19 similarly to the flu, with preventive measures such as an annual vaccination.

When should I get a COVID-19 vaccine?

Like the flu and other respiratory diseases, COVID-19 tends to be more active in the fall and winter, so getting a vaccine in the fall is recommended.

How quickly does the COVID-19 vaccine become effective?

It usually takes about two weeks for the vaccine to become effective. The CDC website provides more information on how the COVID-19 vaccines work.

How long does the COVID-19 vaccine last?

Studies suggest that COVID-19 vaccines are most effective during the first three months after vaccination.

Is it safe to get a flu and COVID-19 vaccine at the same time?

Yes, it safe to get both shots at the same time. Keep in mind that each has similar side effects and you may experience side effects from both.

Is the COVID-19 vaccine safe?

Yes. COVID-19 vaccines approved by the FDA meet rigorous testing criteria and are safe and effective at preventing serious illness, hospitalization and death. Millions of people have received the vaccines, and the CDC continues to monitor their safety and effectiveness as well as rare adverse events.

Where can I get a COVID-19 vaccine?

The COVID-19 vaccine is available at pharmacies. See vaccines.gov to find a convenient location.