Can a Fitbit or Apple Watch
detect the first symptoms of COVID-19 ?

https://medicalxpress.com/news/2020-05-wearables-coronavirus.html

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Also already underway is the Scripps Research Translational Institute's
DETECT (Digital Engagement & Tracking for Early Control & Treatment) Study
to monitor heart rates as a possible way to detect and track coronavirus, flu and other viral infections. As in the other studies, users share the health data captured by the Apple Watch, Fitbit and Garmin devices. For more information on the study, go to the DETECTStudy.org site.

Earlier this year, Scripps' first study on using wearable device data to study flu outbreaks was referenced in The Lancet as "encouraging proof of concept in this direction."

Scripps researchers expanded the flu study to see if
tracking of data (heart rate, activity, and sleep)
using the MyDataHelps mobile app can help predict whether someone will eventually get the flu, COVID-19 or other illness.

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