According to new research, people who reported experiencing side effects to the Pfizer/BioNTech and Moderna Covid-19 vaccines, such as fever, chills or muscle aches, tended to have a greater antibody response after vaccination.
Having such symptoms after vaccination is associated with a greater antibody response compared with pain or rash at the injection site or no symptoms at all, the paper published on Friday suggests. in the JAMA Network Open review.
“In conclusion, these results support the reframing of post-vaccination symptoms as signals of vaccine effectiveness and strengthen guidelines for vaccine boosters in older adults,” the researchers wrote – from Columbia University in New York, the University of Vermont and Boston University – in their article.
But even though some people may have small localized side effects or no symptoms, the vaccine still elicits robust immune responses in them too. Almost all study participants showed a positive antibody response after completing a two-dose Pfizer/BioNTech or Moderna vaccine series.
“I don’t want a patient to say to me, ‘God, I had no reaction, my arm wasn’t sore, I didn’t have a fever. The vaccine didn’t work. I don’t want that conclusion out there,” said Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center and medical director for the National Foundation for Infectious Diseases, who was not involved in the the new study.
“It’s more to reassure people who have had a reaction that it’s their immune system that’s responding, actually quite well, to the vaccine, even though it caused them some discomfort,” Schaffner said.
The researchers analyzed data from 928 adults who self-reported the symptoms they experienced after receiving the Pfizer/BioNTech or Moderna Covid-19 vaccines, and also submitted a dried blood spot to test for antibodies. Most of the participants were white adults, with an average age of 65.
Researchers found that after either vaccine dose, 446 or 48% of participants reported systemic symptoms, while 12% reported only local symptoms and 40% reported no no symptoms.
Meanwhile, antibody reactivity was seen in 444 or 99% of participants with systemic symptoms, 99% of those with local symptoms only, and 98% of those with no symptoms.
“A lot of people have speculated over the years whether people who had more reactions to the vaccine might actually have a more vigorous immune response,” Schaffner said. “And this data seems to support that.”