What you need to know
- COVID-19 infections can cause long-lasting changes to our immune cells, which might make our immune systems less efficient.
- Every time we get infected with the COVID-19 virus, our risk of dangerous health outcomes increases.
- COVID-19 vaccines strengthen our immune systems by teaching cells how to respond to the virus.
COVID-19-related hospitalizations have declined in recent weeks, but JN.1 and other COVID-19 variants are still prevalent throughout the U.S., leaving us vulnerable to infection and post-infection complications.
Every COVID-19 infection puts us at risk of short- and long-term health complications, including immune system dysfunction. Fortunately, COVID-19 vaccines and other COVID-19 mitigation methods make our immune systems smarter.
Read on to learn more about how COVID-19 infections impact our immune systems and how we can safely build protection.
How do COVID-19 infections change our immune systems?
Research shows that COVID-19 infections can cause long-term immune dysfunction. A 2023 study found that COVID-19 infections may reduce our production of “killer T-cells,” which help our bodies fight off infections. This makes our immune systems less efficient, potentially putting us at greater risk of severe illness from future infections.
Another recent study found that our innate immune cells—our immune systems’ first line of defense—change when we become infected with the COVID-19 virus, causing a long-term inflammatory response. That inflammatory response might explain why some people develop long COVID.
How can I safely build immunity against future COVID-19 infections?
Staying up to date on COVID-19 vaccines is a safer and more reliable way to build protection against COVID-19 than getting sick from the virus. COVID-19 vaccines make our immune systems stronger by teaching our cells how to respond to the virus.
The CDC recommends the updated COVID-19 vaccine for everyone 6 months and older. Find appointments near you at Vaccines.gov.
Taking additional steps to reduce your risk of contracting COVID-19 helps prevent immune system damage caused by COVID-19 infection. Wearing a high-quality, well-fitting mask—especially in crowded and indoor spaces—and improving ventilation at indoor gatherings helps reduce your risk of contracting COVID-19.
How do COVID-19 vaccines work?
There are two types of COVID-19 vaccines: messenger RNA (mRNA) vaccines and protein subunit vaccines. All COVID-19 vaccines teach our bodies how to protect us from the virus.
The COVID-19 vaccines created by Pfizer and Moderna use mRNA, which carries information, to teach our cells how to make viral protein. Then, our immune systems recognize the foreign protein and create antibodies that bind to it so the T-cells can destroy them. The antibodies stay in our immune systems and recognize the COVID-19 virus if we become infected, attacking the virus before it can make us seriously ill.
Novavax’s protein subunit vaccine also protects against COVID-19. This type of vaccine introduces a protein from the COVID-19 virus to prompt an immune response.
For more information, talk to your health care provider.
This article is supported by the Centers for Disease Control and Prevention of the U.S. Department of Health and Human Services (HHS) as part of a financial assistance award to the CDC Foundation totaling $69,392,486 with 100 percent funded by CDC/HHS. The contents are those of the author(s) and do not necessarily represent the official views of, nor an endorsement, by CDC/HHS, or the U.S. Government. In addition, the CDC Foundation does not guarantee and is not responsible for the accuracy or reliability of information or content contained in this article. Moreover, the CDC Foundation expressly disclaims all liability for damages of any kind arising out of use, reference to, or reliance on any information contained within this article. This article are not intended as, and should not be interpreted by you as, constituting or implying the CDC Foundation’s endorsement, sponsorship, or recommendation of the information, products, or services found therein.