3rd Doses and Booster Doses

Both 3rd dose and boosters COVID vaccines have different purposes and are intended for different groups of people.  A third dose of the Pfizer and Moderna COVID-19 vaccine can help protect people with weakened immune systems who did not have a strong enough response to the first two doses of the vaccines.  A COVID booster shot is an additional dose of a vaccine given after the protection provided by the original shot(s) has begun to decrease over time.  COVID-19 vaccines continue to be very effective when it comes to preventing hospitalizations and death, but effectiveness against getting the virus may be reduced over time. 3rd doses and boosters increase the strength of your antibody response, and your protection against COVID infection, hospitalization and deaths.

Additional (3rd) Doses

Third doses of Pfizer or Moderna vaccines are available at least four weeks (28 days) after completing the original two-dose vaccine series for individuals age 12 and older in the following categories:

  • Recipients of organ or stem cell transplants
  • People with advance or untreated HIV infection
  • Active recipients of treatment for cancer
  • People who are taking some medications that weaken the immune system

You can get your booster (fourth) dose 6 months after receiving your additional/third dose

Booster Doses

1st booster doses

Available for the following individuals:

  • 18+ and 5 months after second dose of Moderna;
  • 5+ and 5 months after your second dose of Pfizer;
  • 8+ and 2 months since your initial dose of Johnson & Johnson

2nd Booster Doses

Available for the following Individuals, at least 4 months after their first booster

  • Certain immunocompromised persons, as listed above
  • Those over the age of 50

You may choose which vaccine you want to receive as a booster dose unless you are under 18.  Pfizer is the only option for those younger than 18.


Mix and Match boosters

“Mix and match” boosters are authorized by the CDC and FDA.  This means that individuals who received one vaccine for the initial dose or doses can get any of the three available COVID vaccines as a booster.  For instance, if someone completed the Pfizer series 6 months ago, they could now get Moderna as a booster dose.

You may choose which vaccine you want to receive as a booster dose unless you are under 18.  Pfizer is the only option for those younger than 18.

View a COVID-19 3rd dose and booster information sheet HERE.

Locations & Hours

Note that some of our hours have changed.

To schedule an appointment at one of our locations, please call (302) 224-6800.

Please fax all clinical information and/or medical health record information to (302) 322-6201.

Westside’s Provider-On-Call service is available for urgent medical questions or concerns when our office is closed, by calling (302) 655-5822.

For emergencies, dial 9-1-1 or go to the emergency room.

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