Research has shown that vaccinated immunocompromised individuals account for more than 40 percent of breakthrough COVID-19 cases. Knowing that seven million adults are immunocompromised in the United States and that the Delta variant is surging, the Centers for Disease Control and Prevention (CDC) published guidance on the importance of an additional vaccine dose for this population.

The purpose of the additional dose of an mRNA vaccine is to develop as much protection as currently possible against COVID-19.

The guidance came shortly after the U.S. Food and Drug Administration authorized the use of a third shot for people with weakened immune systems. However, healthcare providers typically wait for the CDC’s recommendation before acting.

What Does The Guidance Say?

The CDC is recommending that people who are moderately to severely immunocompromised receive a third dose of mRNA COVID-19 vaccines, either Pfizer-BioNTech or Moderna, after at least 28 days after the administration of the first two doses.

The CDC defines moderately to severely immunocompromised as those:

• Who are receiving active treatment for tumor and cancer affecting blood, bone marrow, and lymph nodes
• Who received an organ transplant and are prescribed immunosuppressive therapy
• Who received CAR-T-cell or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
• With moderate or severe primary immunodeficiency, including DiGeorge syndrome and Wiskott-Aldrich syndrome 
• With Advanced or untreated HIV infection
• Who are receiving treatment with high-dose corticosteroids and other drugs that suppress the immune system

Currently, the Pfizer BioNTech vaccine is recommended for those 12 years and up while the Moderna vaccine is available for people 18 years and up. It is recommended that patients get the same vaccine type they received initially, but if that is not possible, then a dose from the other brand is permitted.

What the Research Says

Researchers have found that:

• Immunocompromised people are more likely to transmit the disease to household contacts.
• They’re also more likely to have a low antibody response to the initial two-dose vaccine series.
• The vaccine is considered 90-94% effective in people without immunodeficiencies, whereas this number declines significantly to a range of 56-72% in those who are immunocompromised.
• Vaccine efficacy is even lower in those who had a solid organ transplant.

Questions You May Have

Won’t the vaccine make me as sick as a COVID-19 infection?

Many immunocompromised individuals are concerned about the misconception that the vaccine contains a live virus, putting their immune systems in a risky situation, but mRNA vaccines do not contain inactivated or attenuated (weakened) pathogens.

Is this the booster shot that’s been mentioned on the news?

This third-dose recommendation differs from a booster vaccine. It is used in those who had a poor response to the two-dose series. As of August 2021, booster vaccines have not yet been approved; however, there is increased speculation that the Biden Administration will soon be recommending a booster be given eight months after patients’ second vaccine dose. 

Is there research to support the safety of a third dose?

Small studies have found zero serious adverse effects in immunocompromised individuals who received an additional dose. Fatigue and pain at injection sites were noted as the most common short-term side effects. However, rare yet serious adverse events, including anaphylaxis and myocarditis and pericarditis in young adults, have been seen in individuals who were administered the initial series. It is unknown if these were immunocompromised patients. 

Do I still need to follow other precautions even when vaccinated?

Immunocompromised individuals should make sure to socially distance themselves at six feet apart from others, wear a mask and avoid large crowds and poorly ventilated indoor places. It is also recommended that those who live with these individuals prioritize vaccination to prevent transmission in the at-risk population. 

What about the Johnson & Johnson vaccine?

Information is not yet available on whether those who are immunocompromised and received the Johnson & Johnson (Janssen) vaccine will have an improved immune response after an additional dose of the same vaccine.

Much about the novel coronavirus, i.e., COVID-19, is still not fully understood. As research progresses and our knowledge of the virus increases, information can change rapidly. We strive to update all of our articles as quickly as possible, but there may occasionally be some lag between scientific developments and our revisions.

More information on this topic can be found in the article “CDC Recommends 3rd Vaccine Dose For Immunocompromised People” on NPR.org. 

*National Center for Immunization and Respiratory Diseases. (2021, August 13). Additional Dose of mRNA COVID-19 Vaccine for Patients Who Are Immunocompromised | CDC. CDC. https://www.cdc.gov/vaccines/covid-19/clinical-considerations/immunocompromised-patients.html