COVID-19 Vaccine Booster Shots and Third Doses

• A COVID-19 booster shot is an additional dose of the vaccine that helps people maintain their level of immunity for longer. Booster doses are given to people who have built enough protection after their vaccine, but that protection decreases over time, a situation called waning immunity.
• A third dose of the COVID-19 vaccine is an additional dose of the vaccine that is given to individuals who cannot build up enough protection when they get the initial vaccination because their immune systems are weakened, a condition called immunocompromise.

The CDC has recommended booster shots for individuals age 5 years and older who have completed a primary series of the Pfizer vaccine (two doses) and for individuals 18 and older who have completed a primary series of the Moderna vaccine (two doses) or the Johnson & Johnson vaccine (one dose).

Individuals who completed the primary series of the Pfizer vaccine become eligible for a booster shot five months after their second dose.

Individuals who completed the primary series of the Moderna vaccine become eligible for a booster shot six months after their second dose.

Individuals who received a single dose of the Johnson & Johnson vaccine become eligible for a booster shot two months after their initial dose.

In addition, individuals 50 and older and certain immunocompromised individuals are eligible to receive a second booster shot of an mRNA COVID-19 vaccine, such as those from Pfizer or Moderna. They can receive this second booster at least four months after their first booster dose of Pfizer, Moderna or Johnson & Johnson vaccine. This second booster dose will increase protection against getting severely ill with COVID-19.

Learn more about COVID-19 booster shots.

The CDC recommends that people who have moderately or severely compromised immune systems receive a third dose of the Pfizer or Moderna COVID-19 vaccine. A third dose can be administered at least 28 days following the two-dose regimen of the same vaccine.

Individuals who are immunocompromised are more likely to get severely ill from COVID-19 and are at a higher risk for prolonged COVID infection and viral shedding. They are also more likely to transmit the COVID-19 virus to household contacts and are more likely to have breakthrough infections.

Individuals with moderate to severe immunocompromise include those who:

• Are in active treatment for solid tumor and hematologic malignancies
• Have received solid-organ transplant and are taking immunosuppressive therapy
• Have received CAR-T-cell or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
• Have moderate or severe primary immunodeficiency (e.g., DiGeorge syndrome, Wiskott-Aldrich syndrome)
• Have advanced or untreated HIV infection
• Are in active treatment with high-dose corticosteroids (i.e., ≥20mg prednisone or equivalent per day), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, tumor-necrosis (TNF) blockers, and other biologic agents that are immunosuppressive or immunomodulatory.

The need for the third dose for this group is not due to a waning effect of the two-dose regimen; rather, data show the standard two-dose regimen does not produce the same degree of protective effect in immunocompromised individuals as it does in people who are not immunocompromised. Patients who are immunocompromised should consult with their health care provider to discuss additional precautions and any questions they may have about protecting themselves from COVID-19.

Learn more about the CDC recommendations for third doses.

Booster shots are intended to bolster the effect of the initial dose(s) of the vaccine. Data has shown that after several months the effectiveness of the vaccine, while still substantial, does decline somewhat. This does not mean that the vaccine is no longer working. According to the CDC, the COVID-19 vaccines still work very well to prevent severe illness, hospitalization, and death, even against the widely circulating Delta variant. However, with the Delta variant, public health experts are starting to see reduced protection against mild and moderate disease. The booster shots will help vaccinated people maintain that protection over the coming months.

The recent emergence of the Omicron variant makes booster shots even more important. Scientists around the world are studying vaccine effectiveness related to this variant, which appears to be highly transmissible. According to the CDC, strong immunity will likely prevent serious illness, and the CDC recommends that everyone 18 and older receive a booster either when they are six months after their initial Pfizer or Moderna series or two months after their initial Johnson & Johnson vaccine.

Booster shots are used for many types of vaccines, such as for tetanus or whooping cough. Unlike an additional dose of vaccine that is given to individuals who are immunocompromised and do not build up enough protection when they get the initial vaccination, booster doses are given to people who have built enough protection after their vaccine, but that protection decreases over time, a situation called waning immunity.

Talk with your health care provider about any questions or concerns you have about getting a COVID-19 vaccine booster shot.

It depends on which COVID-19 vaccine you received first:

• If you received the one-dose Johnson & Johnson vaccine, you are eligible to receive a booster shot at least two months after you received your initial dose of the Johnson & Johnson vaccine.
• If you had the two-dose series of the Pfizer vaccine you can receive a booster shot beginning at least five months after you completed the initial two doses of vaccine.
• If you had the two-dose series of the Moderna vaccine you can receive a booster shot beginning at least six months after you completed the initial two doses of vaccine.

If you are 50 and older or have certain immunocompromising conditions, you are also eligible to receive a second booster dose of an mRNA vaccine such as those from Pfizer or Moderna. You can get a second booster at least four months after you received your first booster shot of Pfizer, Moderna or Johnson & Johnson.

If you are 18 or older, you can receive a single booster dose of any of the available COVID-19 vaccines, regardless of which vaccine you received initially. However, you must meet the eligibility and timing requirements for a booster based on the vaccine you first received.

For example, if you initially had the Johnson & Johnson vaccine, you can receive a single booster dose of the Johnson & Johnson vaccine, the Moderna vaccine, or the Pfizer vaccine as long as you are 18 or older and as long as it has been at least two months since you received your initial dose of the Johnson & Johnson vaccine.

Likewise, if you completed the two-dose series of the Moderna or Pfizer vaccine, you can receive a single booster dose of the Johnson & Johnson vaccine, the Moderna vaccine, or the Pfizer vaccine as long as you meet the eligibility criteria as long as it has been at least six months (for Moderna) or five months (for Pfizer) since you completed your initial two doses of vaccine.

Second booster doses are given only with one of the mRNA vaccines, such as those made by Pfizer and Moderna. You can get a second booster of Pfizer or Moderna at least four months after you received your first booster shot of Pfizer, Moderna or Johnson & Johnson.

Check with the COVID-19 vaccine providers in your community. Booster shots are widely available through pharmacies, local health departments and other providers. Find a vaccine provider in our county-by-county list.

If you or someone you know is homebound in the Finger Lakes Region and would like to receive a first dose, booster shot, or third dose of the COVID-19 vaccine, learn about how to receive vaccine while homebound.

Public health officials ask that you only seek a booster dose if you qualify for one at this time. The FDA and CDC base their authorizations and recommendations on the latest data, updating their guidance as scientists and medical experts review evidence about COVID-19 immunity and each individual COVID-19 vaccine. These science-based recommendations help keep people safe, which is why CDC advises people against seeking booster doses if they are not in the recommended groups.

The COVID-19 vaccines continue to be remarkably effective in reducing fully vaccinated people’s risk of severe disease, hospitalization, and death. If you have questions about your risk of COVID-19, how to protect yourself from COVID-19, or about the vaccines, speak to your health care provider.