Side Effects From COVID Vaccine Show Its Effectiveness

Jay Croft

October 25, 2022

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If you had fever, chills, nausea, or other common side effects to the Pfizer/BioNTech and Moderna COVID-19 vaccines, that's good news.

It means your body had a greater antibody response than people who had just a little pain or rash at the injection site, or no reaction at all.

That's according to new research published in the journal JAMA Network Open .

"These findings support reframing postvaccination symptoms as signals of vaccine effectiveness and reinforce guidelines for vaccine boosters in older adults," researchers from Columbia University in New York, the University of Vermont, and Boston University wrote.

The vaccines provided strong protection regardless of the level of reaction, researchers said. Almost all the study's 928 adult participants had a positive antibody response after receiving two doses of vaccine.

"I don't want a patient to tell me that, 'Golly, I didn't get any reaction, my arm wasn't sore, I didn't have fever. The vaccine didn't work.' I don't want that conclusion to be out there," William Schaffner, MD, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center told CNN.

"This is more to reassure people who have had a reaction that that's their immune system responding, actually in a rather good way, to the vaccine, even though it has caused them some discomfort," said Schaffner, who was not involved in the study.


JAMA Network Open: "Association of Symptoms After COVID-19 Vaccination With Anti–SARS-CoV-2 Antibody Response in the Framingham Heart Study"

CNN: "Covid-19 vaccine study links side effects with greater antibody response"


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