Why is a third dose of the COVID-19 vaccine necessary? Is it not as effective as we thought?

COVID-19 vaccines have been proven safe and highly effective, even against the Delta variant. The CDC’s Advisory Committee on Immunization Practices (ACIP) now recommends an additional dose of the mRNA COVID-19 vaccines (Pfizer and Moderna) specifically for people who are moderately to severely immunocompromised. A third dose will help this vulnerable population enhance their immune response and further protect them from serious – and potentially prolonged – illness.

Why is a third dose only recommended for immunocompromised individuals at this time?

Studies have shown that immunocompromised individuals typically have less of an immune response after initially completing a 2-dose COVID-19 vaccine series than those who are non-immunocompromised. The third dose is intended to help enhance their immune response by increasing antibody levels for greater protection against the virus.

 What are the criteria for receiving a third dose?

Individuals may qualify for a third dose if they are moderately or severely immunocompromised due to a medical condition or receipt of immunosuppressive medications or treatments. This includes people who have: 

• Been receiving active cancer treatment for tumors or cancers of the blood
• Received an organ transplant and are taking medicine to suppress the immune system
• Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
• Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
• Advanced or untreated HIV infection
• Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

Is a doctor’s permission or a prescription required?

No. The CDC has indicated that immunocompromised people will not need a doctor’s permission or a prescription to get a third shot. They will only need to attest that they meet the eligibility requirements for an additional dose. Individuals who are unsure whether they meet the criteria above should consult their provider. 

 Can immunocompromised individuals who initially received the Johnson & Johnson/Janssen COVID-19 vaccine now receive a dose of the mRNA vaccine?

Currently, there are insufficient data to support the use of an mRNA COVID-19 vaccine dose after a single-dose J&J/Janssen COVID-19 vaccination series in immunocompromised people. The FDA and CDC are actively working to provide guidance to immunocompromised individuals who previously received the single-dose J&J/Janssen vaccine.

What if someone has a chronic medical condition like diabetes or asthma? Can they get the third dose now?

These individuals should not receive a third dose at this time. However, it is expected that the general public will be able to get a booster shot sometime this fall. We anticipate that the booster dose will first be available to healthcare workers, first responders and nursing home residents.

What is the difference between a third dose and a “booster” shot? Are they the same thing?

The vaccine dose is the same, but the intended purpose is different. The third dose is intended to improve immunocompromised people’s response to the initial vaccine series. A booster dose is given to people when the immune response to a primary vaccine series is likely to have waned over time.

 How long after completing the 2-dose series should an immunocompromised individual receive a third dose?

The CDC recommends that people with moderately to severely compromised immune systems receive an additional dose of mRNA COVID-19 vaccine at least 28 days after a second dose of the Pfizer or Moderna vaccine.

Where can someone get a third dose?

Check www.vaccines.gov to find a COVID-19 vaccine near you.