What You Need To Know About COVID-19 Booster Shots and Third Vaccine Doses

University of Chicago Assoc. Prof. dr. Emily Landon answers frequently asked questions about supplemental vaccine doses.

Increasingly, research shows that many people with weakened immune systems have not received full protection from their COVID-19 vaccines. Unlike healthy people vaccinated against SARS-CoV-2, the virus that causes COVID-19, immunocompromised people may not produce enough protective antibodies after two doses of the COVID-19 vaccines. This can make them particularly vulnerable to COVID-19, especially as there are more infectious variants circulating in a community.

That’s why federal health authorities announced in mid-August that they would allow immunocompromised people to receive special, extra doses of the Moderna and Pfizer/BioNTech vaccines. This week, US officials also announced that they will be preparing to offer booster shots to healthy, immunized people starting the week of September 20. The boosters will be available to individuals eight months after completing their second dose.

associate Prof. dr. Emily Landon. Credit: UChicago Medicine

In the next question and answer, Assoc. Prof. dr. Emily Landon explains what you need to know about additional vaccine doses COVID-19. Landon, an infectious disease specialist and hospital epidemiologist, is the Executive Medical Director for Infection Prevention and Control at UChicago Medicine and is one of Chicago’s leading experts on the coronavirus.

Am I eligible for a third dose of the COVID-19 vaccine?

In the United States, only people with weakened immune systems are currently eligible for a third dose of the COVID-19 vaccine. The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) says these doses should only go to those who are immunocompromised and who have received the mRNA vaccines made by Pfizer or Moderna for now.

While that is expected to change later this year, this group currently includes patients who have had or will receive:

Organ transplants Stem cell transplants within the last two years Active cancer treatment for tumors or blood cancers and chemotherapy that affects the immune system Severe primary immunodeficiency advanced or untreated HIV Active treatment with high doses of corticosteroids or other drugs that can suppress your immune response .

There isn’t enough data yet to know whether immunocompromised people who received the Johnson & Johnson single-dose vaccine will need another dose, but we expect to know more soon.

You are not currently eligible for a third dose of the vaccine if you are healthy, do not have any of these specific conditions, or are not taking certain immunosuppressive medications. However, if you have received a Moderna or Pfizer vaccine, you will be eligible for a booster shot eight months after your second dose.

Is a third dose the same as a booster dose?

The dosages are the same, but there is a small medical distinction. The term is used differently based on who receives it. Boosters are offered to people who have received the full vaccination course and initially developed a good response, but this decreased over time. Third doses are given to people whose immune systems were unable to fully respond to the initial vaccines. Therefore, the FDA and CDC first recommended an additional dose for immunocompromised individuals.

In the US, federal health officials say they expect boosters to begin the week of September 20. Healthy people who have received the Moderna or Pfizer vaccines are eligible for a booster eight months after their second dose.

Does my booster vaccine have to be the same brand as my original vaccine?

If possible, yes. The CDC recommends booster doses match the original mRNA vaccines people received earlier this year. This next dose should be given at least 28 days after the second dose of the vaccine. If you absolutely cannot find an appropriate dose of vaccine, it would be good to get the other one.

“Boosters are offered to people who have received the full course of vaccination and initially developed a good response, but this decreased over time.”

— Associate. Prof. dr. Emily Landon

If I am immunocompromised, will I be fully protected after I receive my third dose of the vaccine?

New. If you are immunocompromised, a third dose is believed to give you better protection against COVID-19, but you may not get the same level of immunity as healthy people. In studies, most participants who had an immune response to the first two doses did better after a third dose, but some people did not. Being immunocompromised means you still need to take extra precautions to avoid getting COVID-19, such as wearing a mask (especially indoors) and avoiding large crowds or risky activities. Consider wearing eye protection (such as a face shield), especially if you are around unmasked people who may not have been vaccinated.

Discuss your ongoing risk with your healthcare provider and ask them how you can reduce your risk. It is important that your family members and regular close contacts are also vaccinated. This reduces the chance that you will be exposed to COVID-19.

I have a health condition that is not on the CDC’s third dose list. Can I still get my COVID-19 booster shot?

If your health condition is not on the CDC’s third dose list, you are not yet eligible for an additional injection. If you’re not sure if your condition counts, talk to your doctor. Hospitals, doctors’ offices, and pharmacies are only allowed to give third doses to people who should be given the extra doses, according to federal public health authorities. Other people can get booster shots as early as the fall. Federal health officials say people shouldn’t get boosters until eight months after their second dose.

Why didn’t we know earlier that booster doses would be needed?

We are still learning about the COVID-19 vaccines and how well – and for how long – they protect us from the virus and its emerging variants. The CDC’s decision to administer third doses to immunocompromised people was made after data showed that these groups were particularly vulnerable to infection because they had little protection against their previous immunizations. We will continue to learn about these vaccines in the coming months and years, which means we will adjust our vaccine plan accordingly.

Will more people eventually need additional doses of the COVID-19 vaccines?

It’s almost certain that most people will eventually need booster shots or extra doses of the vaccines. However, we are still investigating how long the vaccines will protect people. The good news is that people who are healthy should still have adequate protection against their COVID-19 vaccines. While some healthy, vaccinated people do get COVID-19 infections, they are much less common than unvaccinated people and much less severe. That’s why it’s important that people who haven’t received their vaccine yet get it right away.