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COVID-19 booster shots: Your questions answered

Wellness | Chronic Conditions | October 26, 2021
COVID-19 vaccination card in hands showing booster shot box checked
Boosters are now available for a wide swath of people.

In September, the Food and Drug Administration (FDA) the Centers for Disease Control and Prevention (CDC) recommended a booster shot of the Pfizer vaccine for those 65 and older and those at high risk of illness from COVID-19. The agencies did not recommend booster shots for the general public age 16 and older.

Who is eligible for a booster shot?

Individuals who received a Pfizer or Moderna vaccine are eligible for a booster shot six months or more after completing their initial series:

It’s important to note that the CDC recommends that everyone 65+, those 18+ living in long-term care settings, and those 50-64 with an underlying medical condition get a booster shot. Depending on one’s individual situation, people 18-49 with an underlying medical condition and those 18+ who work or live in high-risk settings may get a booster shot. If you’re unsure about eligibility, speak with your primary care provider.

Individuals 18+ who received the one-dose Johnson & Johnson vaccine are eligible for a booster dose two months after their initial shot. The booster shot may be any of the available vaccines.

Currently, the Pfizer booster shot is only authorized for adults. A decision will be made later as to if and when children aged 12-17, who received the Pfizer vaccine, should receive a booster dose.

Does my booster shot need to be from the same manufacturer?

No. The CDC also approved the mixing and matching of vaccine manufacturers. Eligible individuals may choose which vaccine they receive as a booster dose.

Some people may have a preference for the vaccine type that they originally received and others, may prefer to get a different booster. For example, women under age 50, who are at a higher risk for the very rare but also very serious blood clotting disorder associated with the Johnson & Johnson vaccine, may want to get a Pfizer or Moderna booster instead. Similarly, young men who are concerned about myocarditis and pericarditis after a Pfizer or Moderna vaccination may want to consider the Johnson & Johnson booster as an alternative.

Do boosters mean the vaccines are not working?

No. For most people, the vaccines are doing what they were designed to do: keeping people from getting severely sick or dying. As the delta variant surges across the U.S., those falling seriously ill are overwhelmingly unvaccinated.

Am I getting the same dose as I originally received?

In the case of the Pfizer and Johnson & Johnson vaccines, the booster dose is the same as the original dose. For the Moderna vaccine, it is a half dose.

What are the side effects of the booster shots?

The side effects after getting a booster shot are similar to side effects after the two-shot series. The most common side effects are fatigue and pain at the injection site and overall. Like the two-shot primary series, serious side effects are rare, but may occur. 

Can I get my booster and flu shots at the same time?

Yes. The CDC says you can receive the flu vaccine and a COVID vaccine or booster at the same time. If you have concerns about getting both vaccines at the same time, talk with your healthcare provider.  

Do I still need to follow safety precautions after a booster dose?

Yes. You should continue following safety recommendations after a third or additional dose.

  • Wear a mask in public.
  • Stay 6 feet away from people you don't live with.
  • Avoid crowded and poorly ventilated spaces.

Has the definition of "fully vaccinated" changed?

No. For most people being fully vaccinated means it has been at least two weeks since:

  • A second dose of the Pfizer or Moderna vaccine.
  • One dose of the Johnson & Johnson vaccine.

For some immunocompromised people, fully vaccinated means it has been at least two weeks since receiving a third dose of the Pfizer or Moderna vaccine. 

What's the difference between an additional dose and a booster shot?

Additional dose: When someone with a weakened immune system gets an additional dose of vaccine, it is not a booster. It is part of the first series of shots needed for the person to be fully vaccinated. Many people with impaired immunity did not have a full response to their first doses.

Booster shot: A booster is when someone has a full response to vaccination, but effectiveness wanes over time. The booster re-energizes their immune response.

Who can get an additional dose of the vaccine now?

The FDA has authorized a third dose of the Pfizer or Moderna vaccine for some people with weakened immune systems. The CDC recommends that moderately to severely immunocompromised people who initially received two doses of the Pfizer or Moderna vaccines receive a third dose of mRNA COVID-19 vaccine at least 28 days after a second dose. If you are severely immunocompromised, talk with your doctor about next steps.

Immunocompromised people who got Johnson & Johnson vaccine should follow the same recommendation for everyone else who got Johnson & Johnson, according to the CDC. Meaning they can choose a booster from any of the three vaccine-makers. 

PeaceHealth is offering booster shots to those who are eligible and completed the Pfizer or Moderna regimen at many of our locations. Visit to find a location near you. Booster doses are now widely available at many places, including pharmacies and drug stores. You can find locations by zip code at, by calling 1-800-232-0233, or by texting your zip code to 438829.

Source: CDC

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