What did the research discover?
This study examined whether short-term side effects after receiving an mRNA COVID-19 vaccine are linked to a stronger immune response. Researchers followed 363 adults in the San Francisco Bay Area who received two doses of either the Pfizer (BNT162b2) or Moderna (mRNA-1273) vaccine and had no prior COVID-19 exposure. They measured neutralizing antibodies (nABs)—which help protect against infection—one month and six months after vaccination.
The study found that people who experienced chills, tiredness, feeling unwell, or headaches after the second dose had 1.4 to 1.6 times higher nAB levels at both time points compared to those who did not have these symptoms. Additionally, more severe side effects and increased body temperature or heart rate after vaccination were linked to even higher antibody levels. For example, a 1°C rise in skin temperature was associated with 1.8 times higher nAB levels after one month and 3.1 times higher levels after six months.
These findings suggest that experiencing temporary side effects after vaccination could be a sign of a stronger and longer-lasting immune response.
How can I apply this information?
If you experience fatigue, chills, or other mild symptoms after a COVID-19 vaccine, this study suggests that your immune system may be building stronger protection. Rather than being a negative outcome, side effects could indicate that your body is responding well to the vaccine.
This information could help address vaccine hesitancy, as concerns about side effects are a major reason why some people avoid vaccination. Understanding that temporary symptoms may signal a better immune response could encourage more people to get vaccinated, especially as booster uptake remains low.
Because this is research, more studies are needed to confirm these findings for updated vaccines and individuals with prior COVID-19 infections. However, these results suggest that short-term vaccine side effects may be a positive sign of strong immunity rather than something to be feared.
Source:
Dutcher EG, Epel ES, Mason AE, Hecht FM, Robinson JE, Drury SS, Prather AA. COVID-19 vaccine side effects and long-term neutralizing antibody response: a prospective cohort study. Annals of Internal Medicine. 2024 Jul;177(7):892-900. https://pubmed.ncbi.nlm.nih.gov/38857503/
