Key Takeaways

In President Joe Biden’ssix-pronged planto combat the spread of the Delta variant, booster shots are a prominent piece. Boosters are authorized for all three of the available COVID vaccines in the United States.

In addition to the previously authorized additional doses for moderately to severely immunocompromised individuals, the Centers for Disease Control and Prevention (CDC) now recommends a COVID-19 booster for everyone 5 years and older who:

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But some scientists are asking if healthy Americans need booster shots. Continuing clinical trials show that antibodies from the Pfizer-BioNTech and Moderna vaccines slowly decline starting around six months.

Antibodies Are Only One Line of Defense

“What we’re seeing is that there are good immune memory cells that we can look at both their quality and their quantity,” Pepper said. “And more importantly, we are not seeing studies that are showing increases in disease. That’s what we have to look at with these vaccines: are they preventing disease? They are largely still doing that.”

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Pepper explained that while antibody levels may gradually decline, they are not the only line of defense against infection and disease.

“What we need to remember is that antibodies are like a force field,” Pepper says. “If you’ve seen ‘The Incredibles,’ that is the force field that is sent out to protect the family. But if the infection gets past the antibodies, if there are holes in the force field, or that force field begins to wane, there’s still this whole team of superheroes underneath it.”

B and T Cells Work Behind the Scenes

The superheroes in this case are B cells and T cells, also known as the lymphocytes that make up part of the adaptive immune system.

When a vaccine is administered, whether it’s conventional or mRNA, the vaccine material communicates primarily with the B and T cells. It activates them to attack incoming viral or bacterial cells.

B cells are primarily responsible for producing antibodies. Still, even after that functionality wanes, they retain the memory of how to produce those antibodies in the event they encounter the same or similar pathogen in the future.

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Pepper states that during the contraction phase of the body’s immune response, the body produces roughly 10% more immune cells, specifically B and T cells. While there may not be as many B cells over time, they retain the memory of producing antibodies so they can make them quickly when needed.

Even within the category of B cells, specialization occurs, creating plasma cells that produce antibodies for the person’s lifetime and memory B cells that patrol for viral cells.

So are there are as many antibodies? No. But if COVID-19 were detected, the memory B cells would ramp up antibody production and attack the virus in hours rather than days, lessening the severity of symptoms.

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T-cells support the work of B cells and specialize as well. Some aid B cells in their functionality, while others directly attack infected cells. Between the two types of immune cells, they create an ongoing web of protection.

There’s a Reason for Waning Antibodies

As an HIV researcher,Monica Gandhi, MD, MPH, professor of medicine and associate division chief of the Division of HIV, Infectious Diseases, and Global Medicine at UCSF/San Francisco General Hospital, knows the importance of B and T cells.

HIV attacks T cells to destroy the immune system. At the webinar, she pointed out that there is a reason for decreased antibody production.

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Antibodies should be produced on an as-needed basis. B and T cells help them do that.

So, even though antibodies are only one part of the immune equation, why have we placed so much emphasis on them? The answer lies in testing.

“It’s a lot easier to take blood and measure the antibody levels than it is to find and track these elusive, specialized cells,” Pepper said.

There is only onecommercially available testfor T cell analysis at the moment, making antibodies the most accessible yardstick for immune response.

What This Means For You

Immunocompromised People Are the Exception

Giving boosters to immunocompromised patients ”makes sense,” Gandhi said. “We’ve always done that with immunocompromised patients [because] they may need a little more to build up their B cell and T cell memory.”

But outside of those with severe immunocompromised conditions such as cancer, HIV, or certain blood diseases, Gandhi emphasizes that the booster may just not be necessary.

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All studies have shown consistent protection against severe disease, Gandhi adds. Even if an immunocompromised person encounters the virus, the likelihood of hospitalization is extremely low.

Since eradication is likely not on the table for the foreseeable future, scientists and the World Health Organization(WHO) are urging leadersto focus on initial vaccination for all people rather than booster shots for those already protected.

Correction:A previous version of this article stated there were no commercially available tests for T cell analysis. It was updated on September 20 to include the T-Detect COVID test.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit ourcoronavirus news page.

2 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.COVID-19 vaccine booster shots.Thomas SJ, Moreira ED, Kitchin N, et al.Six month safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine.MedRxiv. Preprint posted online July 28, 2021. doi:10.1101/2021.07.28.21261159.

2 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.COVID-19 vaccine booster shots.Thomas SJ, Moreira ED, Kitchin N, et al.Six month safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine.MedRxiv. Preprint posted online July 28, 2021. doi:10.1101/2021.07.28.21261159.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Centers for Disease Control and Prevention.COVID-19 vaccine booster shots.Thomas SJ, Moreira ED, Kitchin N, et al.Six month safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine.MedRxiv. Preprint posted online July 28, 2021. doi:10.1101/2021.07.28.21261159.

Centers for Disease Control and Prevention.COVID-19 vaccine booster shots.

Thomas SJ, Moreira ED, Kitchin N, et al.Six month safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine.MedRxiv. Preprint posted online July 28, 2021. doi:10.1101/2021.07.28.21261159.

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