Who Can Get COVID Booster Shots and When Can They Get Them? Here's What to Know

With COVID booster shots now approved for some people with compromised immune systems, who can get the shots and when?

U.S. regulators authorized an extra dose of the Pfizer or Moderna COVID-19 vaccines for people with compromised immune systems last week.

The U.S. Centers for Disease Control and Prevention advisory panel also recommended the extra shot Friday.

Here's what we know so far.

Who is eligible for booster shots under the newest guidance?

The announcement applies to several million Americans who are especially vulnerable because of organ transplants, certain cancers or other disorders and who received the Moderna or Pfizer COVID vaccines.

According to the CDC, the list 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

The agency notes that "people should talk to their healthcare provider about their medical condition, and whether getting an additional dose is appropriate for them."

What about those who got the Johnson & Johnson vaccine?

 The FDA and CDC’s approval and recommendation does not apply to immunocompromised individuals who got the Johnson and Johnson vaccine.

"There is not enough data at this time to determine whether immunocompromised people who received the Johnson & Johnson’s Janssen COVID-19 vaccine also have an improved antibody response following an additional dose of the same vaccine," the CDC states.

Why should immunocompromised people get a third shot?

The announcement comes as the extra-contagious delta version of the coronavirus surges through much of the country, pushing new cases, hospitalizations and deaths to heights not seen since last winter.

It’s harder for vaccines to rev up an immune system suppressed by certain medications and diseases, so those patients don’t always get the same protection as otherwise healthy people — and small studies suggest for at least some, an extra dose may be the solution.

"There has been a number of studies looking at how well does the vaccine perform in people with different underlying conditions? And the vaccine performs beautifully in the huge majority of Americans, but in people who are severely immunocompromised, for example after an organ transplant or people who are undergoing chemotherapy or who are on severe immune suppressing medications - not surprisingly, the goal of those medications and treatment is to suppress the immune system and so we don't see the immune system, in some cases, learning the lesson as well about how to fight off COVID," Chicago Department of Public Health Commissioner Dr. Allison Arwady said Thursday morning.

Do immunocompromised people need to get a third shot of the same vaccine they already received?

According to the CDC, "a third dose of the same mRNA vaccine should be used."

"A person should not receive more than three mRNA vaccine doses. If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered," the agency's website states.

When can eligible people get their third dose?

The FDA determined that transplant recipients and others with a similar level of compromised immunity can receive a third dose of the vaccines from Pfizer and Moderna at least 28 days after getting their second shot.

Chicago's top doctor says the city is "absolutely ready" to administer booster vaccines to people with compromised immune systems should the Food and Drug Administration approve it.

"We are absolutely ready," Arwady said. "We have vaccine available, especially because if this recommendation comes through, it would be for probably 2-3% of eligible Chicagoans where we think about even... kind of the outside estimate of who this might include."

Walgreens announced Friday that its pharmacies will offer additional COVID-19 vaccine doses to eligible patients.

“Walgreens is committed to administering COVID-19 vaccines to our most vulnerable populations as quickly and safely as possible,” said Kevin Ban, Walgreens Chief Medical Officer. “As one of the first companies to begin providing these vaccines, we have an experienced team of pharmacists and technicians, as well as the infrastructure to support the increased demand for these vaccines.”

Walgreens has begun offering same-day appointments available on a walk-in basis at select stores, the company said. Patients will bring their vaccination card or record to the appointments to prove eligibility.

Are there any risks with getting a third dose? What about side effects?

The CDC reports there is "limited information about the risks of receiving an additional dose of vaccine, and the safety, efficacy, and benefit of additional doses of COVID-19 vaccine in immunocompromised people continues to be evaluated."

The agency noted that side effects with the third shot "were similar to that of the two-dose series."

The most common symptoms include fatigue and pain at the injection site, but "most symptoms were mild to moderate."

As with previous doses of the vaccine, the CDC notes that, "serious side effects are rare, but may occur."

What about people without compromised immune systems?

U.S. health officials are continuing to closely monitor if and when average people’s immunity wanes enough to require boosters for everyone — but for now, the vaccines continue to offer robust protection for the general population.

The CDC says it does not recommend additional doses or booster shots for any other population at this time.