JMIR Publications

ABSTRACT

Background:

The Pfizer COVID-19 Vaccine employs a novel technology which utilizes messenger Ribonucleic Acid (mRNA) to deliver viral proteins to the host and elicit a protective immune response, but the short-term physiologic response to the vaccine has yet to be studied using wearable devices.

Objective:

Using wearable devices, we aim to characterize physiologic changes in response to COVID-19 vaccination in a small cohort of subjects.

Methods:

In this prospective observational study, physiologic data from 19 internal medicine residents at a single institution who received both doses of the Pfizer COVID-19 vaccine were collected using the WHOOP strap 3.0 to determine participant baseline resting heart rate (RHR), heart rate variability (HRV), respiratory rate (RR), and sleep duration. Primary outcomes included change from baseline in HRV, RHR, RR, and sleep duration. Percent change and standard deviation from baseline (defined as the 30 days of wear prior to vaccination) were calculated for six days after the first and second dose of the Pfizer COVID-19 for all participants who met inclusion and exclusion criteria. Symptom type, severity, and duration were reported as secondary outcomes.

Results:

In 19 individuals, mean age 28.8 (+/- 2.2), 53% female, percent change in HRV was decreased on day 1 (-13.44% +/- 13.62%) following administration of the first vaccine dose, and this response was blunted following dose 2 (-9.25% +/- 22.6%). RHR had a slight initial increase (+2.73% +/- 5.50%, +4.20% +/- 9.42%) after each dose and normalized after one day and RR showed no change compared to baseline after either vaccine dose. Sleep duration was increased up to 6 days post vaccine and peaked on day 3. Increased sleep duration prior to vaccine also demonstrated a more significant change in HRV compared to those who were sleep deprived (as determined by Pearson correlations). A more robust response in terms of symptom severity and duration was seen following dose 2. Arm soreness was the most reported symptom for both doses.

Conclusions:

This represents the first observational study of the physiologic response in humans to any of the novel COVID-19 vaccines, as measured using wearable devices. We provide evidence that HRV decreases in response to both vaccine doses, with no consequent changes in RHR or RR. Sleep duration initially decreased following each dose and subsequently increased thereafter. Future studies with a larger cohort and comparison to other inflammatory and immune biomarkers, such as antibody response, will be needed to determine the true utility of this type of continuous wearable monitoring in regards to vaccine responses. Our data raises the possibility that increased sleep prior to vaccination may impact physiologic response, which could be used to track immune response to vaccination. Clinical Trial: NCT04304703: https://www.clinicaltrials.gov/ct2/show/NCT04304703