CDC officially recommends third vaccine dose for immunocompromised

The Centers for Disease Control and Prevention (CDC) on Friday officially recommended an additional dose of coronavirus vaccines for certain people with compromised immune systems, clearing the way for doses to be administered to several million Americans as soon as possible.

CDC Director Rochelle WalenskyRochelle WalenskyCDC working to tighten testing requirement for international travelers Overnight Health Care — Presented by March of Dimes — Omicron sets off a flurry of responses CDC strengthens recommendation to say all adults should get booster shot MORE signed off on the recommendation for people with moderate to severely compromised immune systems only a few hours after it was unanimously endorsed by the agency's Advisory Committee on Immunization Practices.

The CDC said the recommendation was needed because data increasingly show some people with moderately to severely compromised immune systems do not always build the same level of immunity compared to people who are not immunocompromised.


In a statement, Walensky said the recommendation is "an important step in ensuring everyone, including those most vulnerable to COVID-19, can get as much protection as possible from COVID-19 vaccination."

"At a time when the Delta variant is surging, an additional vaccine dose for some people with weakened immune systems could help prevent serious and possibly life-threatening COVID-19 cases within this population," Walensky added.

The recommendation is only for the mRNA vaccines from Pfizer-BioNTech and Moderna. People as young as 12 years old who are immunocompromised would be eligible for Pfizer-BioNTech; the Moderna vaccine is for those 18 and older.

The additional doses are not considered boosters, because they are considered part of the primary vaccine series. 

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

The agency's narrow definition of immunocompromised includes people undergoing treatment for solid tumors or blood cancers; organ transplant patients, including those who have gotten a stem cell transplant within the last two years; and people with advanced or untreated HIV.


The CDC has estimated that about 2.7 percent of U.S. adults are immunocompromised, or about 7 million people.

However, there is no requirement for people to show proof that they meet the definition. Patients will only need to attest to pharmacists that they fall into one of the specific categories. 

Some CDC advisory panel members expressed concern that relying on the honor system would be confusing, and open the door to people with other types of conditions that affect the immune system.

However, other panel members noted that self-attesting is the most equitable way to ensure people who need the extra dose get it. Requiring a doctor’s note could deter people without health insurance or a primary care physician.

Neither the CDC nor the Food and Drug Administration recommend booster doses for the general population, though the CDC said that more than 1 million people in the U.S. have received unauthorized booster shots of the Moderna or Pfizer vaccines. About 90,000 people have received an additional dose of the Johnson & Johnson vaccine.

During a White House briefing on Thursday, Walensky warned that Americans getting unauthorized booster shots undermine the agency's safety monitoring of recipients.

Health officials have left the door open to booster doses, stating that they may be needed eventually.

The U.S. has plenty of extra doses available. But demand for a third dose among people who don't necessarily need it would be controversial given that many people around the world, including health care workers in some countries, are still waiting for their first dose.

Walensky said immunocompromised people are especially vulnerable to COVID-19 because they are more at risk of serious, prolonged illness. 

While vaccination is likely to increase protection for them, Walensky said people with moderate to severe immune weakness should still maintain precautions to help prevent COVID-19, like masking, physical distancing and avoiding crowds.