Developed by American pharmaceutical company Pfizer and German firm BioNTech, this COVID-19 vaccine has been approved for emergency use by the U. S. Food and Drug Administration (FDA) for people age 16 and older. The approved vaccine has been given the brand name Comirnaty.

  • The distribution of this vaccine began in December 2020 under FDA Emergency Use Authorization (EUA) that made the vaccine available for people age 16 and up. On August 23, 2021, the Pfizer vaccine received full FDA approval for people age 16 and up.
  • In May 2021, the EUA was expanded to include children ages 12 to 15. That EUA is still in effect, and this age group is still able to receive the vaccine.
  • In August 2021, the EUA was updated to authorize a third dose in moderately to severely immunocompromised people age 18 and up. That EUA is still in effect.

Important Information about the Pfizer Vaccine

  • Number of doses required: 2 doses of the same vaccine
  • Time between doses: Minimum of 21 days
  • Third dose for immunocompromised people: Yes
  • FDA status: Ages 16 and up (FDA-approved); ages 12-15 (FDA EUA)
  • Time to reach full protection: 14 days after second dose
  • Effectiveness: Highly effective in preventing severe illness, hospitalization and death
  • How long protection will last: Unknown at this time; studies are ongoing
  • Storage: Ultracold temperature as low as -112 degrees Fahrenheit

How the Pfizer Vaccine Works

Both the Pfizer and Moderna COVID-19 vaccines are based on messenger RNA (mRNA) technology. mRNA vaccines contain a code that provides the cells "instructions" to create antibodies to protect against COVID-19. Learn more about how mRNA vaccines work.

This type of vaccine does not contain any part of the virus, so it cannot cause COVID-19.

Who Can and Cannot Get the Pfizer Vaccine

The vast majority of people are able to get the Pfizer vaccine or any of the other approved vaccines. However, a few groups of people cannot receive it or should consult a doctor first.

  • Children under the age of 12 are not eligible to receive the Pfizer vaccine at this time; studies are underway to test its safety and effectiveness in children.
  • Pregnant women, as well as those who are breastfeeding or may become pregnant, may receive the Pfizer vaccine. The CDC has recommended that women who are pregnant, breastfeeding or plan to become pregnant be vaccinated against COVID-19. Please see the recommendations from the CDC about COVID-19 Vaccines While Pregnant or Breastfeeding.
  • People who are allergic to any of its ingredients or had an allergic reaction to their first dose cannot receive this vaccine. Please see additional information about allergic reactions below.

Third Dose for Immunocompromised People

In August 2021, both the FDA and the CDC approved a third dose of mRNA vaccines (Pfizer and Moderna) for moderately to severely immunocompromised people age 18 and up, to be given 28 days or more after their second dose of the vaccine.

For more information, please see the CDC's recommendations for immunocompromised people.

How the Pfizer Vaccine Was Developed

Although the Pfizer vaccine was developed quickly, it still underwent the same rigorous approval process as laid out by the FDA. No safety steps were skipped. Learn more about the vaccines' development and approval process.

In May 2020, the University of Maryland School of Medicine (UMSOM) became the first in the United States to begin testing this COVID-19 vaccine candidate. Learn more about how we're fighting COVID at the University of Maryland Medical System.

Allergic Reactions and Side Effects

Please see the FDA's Fact Sheet for the Pfizer vaccine or the most up-to-date information on:

  • Vaccine ingredients
  • Side effects and what to do about them
  • Possible allergic reactions

If you have a history of immediate or severe allergic reaction to anything – especially another vaccine or injectable medicine – it is strongly recommended you talk to your doctor before getting the vaccine. This is so your doctor can confirm it is safe for you to get the vaccine.

If you have a history of severe allergic reactions, you will also be monitored for 30 minutes after your vaccination.

Other Conditions

Before you get vaccinated, you should talk to your doctor if you:

  • Have any allergies
  • Have a fever
  • Have a bleeding disorder or are on a blood thinner
  • Are immunocompromised or are taking a medicine that affects your immune system
  • Have received another COVID-19 vaccine

Updated 8/30/2021

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