More than 100 million Americans have received full courses of a COVID-19 vaccine.

The three vaccines available in the U.S. — Pfizer-BioNTech, Moderna, and Johnson & Johnson/Janssen (J&J) — are all safe and effective against COVID-19. They are especially effective in preventing severe illness, hospitalization, and death.

However, according to the U.S. Department of Health and Human Services and other health officials, protection from the COVID-19 vaccine can decrease over time. Some people — such as those with compromised immune systems — also may not have had a strong immune reaction to their initial doses of vaccine. And the highly contagious Delta variant (B.1.617.2) is causing COVID-19 cases to rise in the U.S. and worldwide.

With those factors in mind, many people are wondering if they need to receive an additional shot of the COVID-19 vaccine.

What Is a Booster Shot?

Protection from many vaccines begins to decrease over time. Booster shots are additional doses of a vaccine, meant to help your immune system recharge protection against the disease.

Booster shots are common for many vaccines, including:

  • Tetanus, diptheria, and pertussis (Tdap).
  • Measles-mumps-rubella (MMR).
  • Hepatitis A and B.

People often receive booster shots for vaccines throughout their lives. For instance, you may need a tetanus booster about every 10 years to ensure protection.

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COVID-19 and Booster Shots

Factors that could influence an additional shot of the COVID-19 vaccine include:

  • Your immune system didn’t have a strong response to the initial doses of the vaccine series. This may be the case for people who are immunocompromised after receiving solid organ transplants or for other reasons.
  • Your immune system had strong protection against COVID-19 after your initial vaccine series, but it’s beginning to decrease.
  • The SARS-CoV-2 virus that causes COVID-19 has changed enough that another dose of vaccine is needed to protect against it.

The COVID-19 vaccines are safe and effective in preventing serious infections from SARS-CoV-2 and its variants, including the Delta variant. However, it is still possible to get infected and to spread the virus — even if you’ve been vaccinated.

Will There Be a COVID-19 Booster Shot?

On Aug. 12 and Aug. 13, 2021, the U.S. Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) announced that immunocompromised people who received the first two doses of the Pfizer or Moderna COVID-19 vaccines were eligible for an additional dose of those vaccines.

Immunocompromised people have a medical condition or treatment that impairs their immune system’s ability to fight the virus. Their immune system also may not have had a strong response to the initial vaccine series.

If you are immunocompromised, you can get a third dose of the Pfizer and Moderna vaccine now. Those eligible include solid organ transplant recipients, many cancer patients, and others who are immunocompromised. For more information, visit or call 844-876-2822 between 8 a.m. and 5 p.m., seven days a week.

The FDA and CDC also have authorized a third “booster” dose for people who received the Pfizer and Moderna vaccines. To be eligible, you must be 18 and older and must have received your second dose of those vaccines at least six months ago.

The CDC and FDA also have authorized a booster dose for recipients of the J&J vaccine. To be eligible, you must be 18 and older and must have received your J&J vaccine at least two months ago.

For the booster dose, you can receive any of the three available vaccines: Pfizer, Moderna, or J&J.

Why Do We Need Another COVID-19 Shot?

The COVID-19 vaccines are safe and effective, especially in preventing severe cases of COVID-19 — and deaths.

However, data suggests that protection from the vaccines may decrease over time. An additional shot can help maintain or improve your immune system’s protection against SARS-CoV-2 and its variants.

Also, research shows that some people don’t have a strong immune reaction to the initial doses of vaccine. That’s the case for many immunocompromised people, such as organ transplant recipients.

When Can I Get the Additional COVID-19 Shot?

In line with the FDA’s and CDC’s announcements, UPMC is currently offering a third dose of the Pfizer and Moderna vaccines to immunocompromised patients who received the first two doses. At least 28 days must have passed since your second dose of the vaccine. We recommend getting the same vaccine as your first two doses.

We also are offering a booster dose for Pfizer, Moderna, and J&J recipients who are 18 and older. Pfizer and Moderna recipients are eligible for a booster six months after their second dose. J&J recipients are eligible two months after their initial dose.

According to the CDC and FDA, people who are eligible for this booster dose can choose which vaccine they wish to receive as a booster — even if they didn’t receive that vaccine as part of their initial series.

If you are eligible and would like to schedule an appointment for an additional dose, visit or call 844-876-2822 between 8 a.m. and 5 p.m., seven days a week.

You must have an appointment to get an additional dose of the vaccine. We are not offering additional doses on a walk-in basis.

On the day of your appointment, please bring your CDC vaccination card.

Do I Still Need to Wear a Mask?

The vaccine represents a crucial step in preventing COVID-19. However, masking and social distancing also can provide important protection — especially if you’re immunocompromised.

After getting an additional dose of the COVID-19 vaccine, you should continue to follow any laws, regulations, or guidelines about wearing a facemask. The CDC recommends even fully vaccinated people wear a mask and physically distance while in public in areas with high rates of transmission.

At UPMC, we strongly encourage people who are eligible for the COVID-19 vaccine to get vaccinated. Americans 5 and older are eligible to get the vaccine. For more information on the vaccine, visit

Editor's Note: This article was originally published on .


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About UPMC

Headquartered in Pittsburgh, UPMC is a world-renowned health care provider and insurer. We operate 40 hospitals and 700 doctors’ offices and outpatient centers, with locations in central and western Pennsylvania, Maryland, New York, and internationally. We employ 4,900 physicians, and we are leaders in clinical care, groundbreaking research, and treatment breakthroughs. U.S. News & World Report consistently ranks UPMC Presbyterian Shadyside as one of the nation’s best hospitals in many specialties and ranks UPMC Children’s Hospital of Pittsburgh on its Honor Roll of America’s Best Children’s Hospitals.