Association of symptoms after COVID-19 vaccination with antibody response

Editor's Note

This study by investigators in the Framingham Heart Study—an ongoing, prospective cohort study evaluating cardiovascular disease risk factors—finds that systemic symptoms after COVID-19 vaccination were associated with greater antibody response than local only or no symptoms.

A total of 928 of 3,200 Framingham Heart Study participants completed this study. After either the first or second vaccine dose, 446 (48%) participants reported systemic symptoms, 109 (12%) reported local symptoms only, and 373 (40%) reported no symptoms.

In bivariate analysis, symptoms were associated with younger age, female gender, prior infection, and the Moderna vaccine. Antibody reactivity occurred in 365 (98%) asymptomatic participants, 108 (99%) with only local symptoms, and 444 (99%) with systemic symptoms.

In adjusted models, systemic symptoms were linked to greater antibody response, but associations were weakened with adjustment for confounders. Similar results occurred when participants with prior COVID-19 infection were excluded.

The results support reframing post-vaccination symptoms as signals of vaccine effectiveness and reinforce guidelines for vaccine boosters in older adults, the researchers say.