Study reports that Apple watches require further evaluation to determine their ability to predict COVID-19 infection due to small study size, self-reported data, and a small number of infections within the group.

Medical Mythbusting Commentary for January 18, 2021

Source:
Study suggests Apple Watch can detect COVID-19 before symptoms appear

Reference:

Longitudinal Physiological Data from a Wearable Device Identifies SARS-CoV-2 Infection and Symptoms and Predicts COVID-19 Diagnosis