Staying Healthy
Side effects after a COVID shot indicate it's working
In the journals
- Reviewed by Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
One reason people avoid getting a COVID booster is concern about side effects like fatigue, achiness, muscle and joint pain, chills, headache, and fever. But a new study found that these symptoms indicate a robust immune response to the vaccine that increases antibody levels and offers extra protection against the virus.
Researchers examined the antibody responses and side effects from 363 people who had the two-dose Pfizer-BioNTech or Moderna mRNA vaccines. One month after the second dose, they found that those who cited at least one side effect, such as chills, fatigue, headache, or generally feeling unwell, had antibody levels 1.4 to 1.6 times higher than those who reported no symptoms. The researchers found that these levels were still elevated six months later.
Of note, COVID vaccines increase antibody levels in almost everyone who gets vaccinated even if they have no symptoms. The study was published online June 10, 2024, by Annals of Internal Medicine.
Image: © Jacob Wackerhausen/Getty Images
About the Author
Matthew Solan, Executive Editor, Harvard Men's Health Watch
About the Reviewer
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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