Inter-individual variation in objective measure of reactogenicity following COVID-19 vaccination via smartwatches and fitness bands

This study investigated the possibility of detecting individual physiological responses to COVID-19 vaccination using consumer wearable devices. Data from 5674 participants in the DETECT study who received mRNA vaccines were analyzed. Resting heart rate (RHR) increased after vaccination, peaking on day 2 and returning to normal by day 6. This increase was greater than one standard deviation above baseline in 47% after the second dose. The effect was stronger after the second dose than the first (except in those with prior COVID-19 infection), more pronounced with the Moderna vaccine, and greater in females (first dose only) and individuals under 40. These findings suggest that wearable sensors can detect objective evidence of reactogenicity, potentially serving as a surrogate for vaccine-induced immune response.

Giorgio Quer, Matteo Gadaleta, Jennifer M. Radin, Kristian G. Andersen, Katie Baca-Motes, Edward Ramos, Eric J. Topol, Steven R. Steinhubl