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COVID-19, delta and the immunocompromised: Will booster shots help?

The FDA has authorized vaccine booster shots for certain people with immune deficiencies, and the CDC recommends them. Should you get a booster?

People looking puzzled (illustration) Illustration: Getty Images

Updated August 16, 2021, to include CDC recommendation. This information is accurate as of the update date.

By Esther Benenson

The delta variant is more contagious than previous forms of the virus that causes COVID-19. It spreads much more rapidly and its symptoms are even more severe. Most COVID-19 hospitalizations in this country are due to the delta variant. 

Although vaccination is highly effective at preventing hospitalizations and death, people who are immunocompromised may not respond to the COVID-19 vaccine.

The Food and Drug Administration (FDA) has granted emergency use authorization for vaccine booster shots for certain people who are immunocompromised, and the Centers for Disease Control and Prevention (CDC) is now recommending them. Are booster shots the answer?

Here, VCU Health answers these questions and more on the safety and effectiveness of the COVID-19 vaccine for people who are immunocompromised and whether booster shots will help.

What is the immune system?

The immune system refers to your body’s means of attacking invading pathogens, like viruses and bacteria, after they enter your body. Your immune system attacks these pathogens to prevent them from harming your organs and tissues. Some of these invading pathogens are merely annoying, like a cold. Others, like the virus that causes COVID-19, can be deadly.

What does it mean to be immunocompromised?

Being immunocompromised means your body’s immune system is unable to keep you safe from invading agents, like viruses and bacteria.

What diseases, conditions and treatments can weaken your immune system and cause you to be immunocompromised?

More than 200 diseases cause immune system issues. These include:

  • Cancers that affect the bone marrow, such as leukemia and lymphoma
  • Insufficiently controlled diabetes (type 1 and type 2)
  • Advanced human immunodeficiency virus (HIV) infection — particularly in patients not on treatment with low CD4 counts

Sometimes it’s the treatment for a medical condition that can weaken your immune system. These include but are not limited to:

  • Some chemotherapy to treat cancer
  • Immunosuppressant drugs for transplant recipients
  • Steroids, used to treat a wide variety of diseases and conditions

What does the immune system have to do with COVID-19?

When your immune system doesn’t work well, viruses, such as the virus that causes COVID-19, can enter your body undetected and are given free reign. During a pandemic, viruses pass from one person to another quickly and easily. People with a healthy immune system have a greater chance at fighting the infection than those whose immune system is weak.

The virus that causes COVID-19 is highly lethal, and the delta variant even more so. Even people with a healthy immune system are succumbing to infection, severe symptoms and death. People without a properly functioning immune system have an even harder time fighting the infection.

Vaccines work by teaching your body how to produce antibodies to fight an infection before the infection actually takes place. That way your body is primed to fight off the invading pathogens as soon as they appear. 

People with weakened immune systems are at a disadvantage for two reasons:

  1. Their immune system may not be strong enough to fight off infection on its own.
  2. Their immune system may not be sufficiently strengthened by a vaccine to fight off infection.

Nonetheless, it is possible that someone who is immunocompromised may respond sufficiently to vaccination, so vaccination is critical to help prevent infection to the maximum extent possible.

Is it safe for people with weakened immune systems to get the vaccine?

Yes. All of the currently available COVID-19 vaccines in the United States are safe for people who are immunocompromised. They do not contain live coronavirus. No one can get COVID-19 from the vaccine. Without it, you are completely open to infection and the severe results of COVID-19, including death. More than 600,000 people in the United States have died from COVID-19.

Data show that people who are immunocompromised do not respond to the current vaccines as robustly as people who are not immunocompromised. That said, a significant proportion will respond, and any potential protection is better than no protection. Booster shots, as authorized by the FDA, may help fill in the gap.

Can people who are immunocompromised now get the booster shot?

The FDA has authorized a third mRNA shot for people who are moderately to severely immunocompromised, and the CDC now recommends it. The authorization applies in this country to the Pfizer and Moderna vaccines. The Virginia Department of  Health has updated its vaccination guidelines to include this provisionThe emergency use authorization is for booster shots in people who have a history of solid organ transplantation or have an equivalent level of immuncompromise.

Information on how people can get the booster shots will be forthcoming. Meanwhile, scientists are continuing to study whether a booster shot will be helpful for the rest of the population.

What else can people with weakened immune systems do to lower their risk of COVID-19?

Follow the same practices the CDC and FDA have been advising all along for unvaccinated people, but with even greater diligence:

  • Wear a face mask, especially when indoors
  • Maintain a distance of at least six feet from others
  • Minimize time spent in indoors around crowds
  • Wash your hands frequently or use alcohol hand sanitizer
  • Continue to watch for updated guidance from the CDC and the Virginia Department of Health

Talk to your doctor about any additional concerns you may have.

For more information

For a variety of news and information on COVID-19 and how VCU Health is keeping patients safe, please visit our COVID-19 News Center

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