A smart wearable ring which can reliably detect the onset of fever may help curb the spread of Covid-19 say researchers. The ring that can be worn on the finger records temperature heart rate respiratory rate and levels of activity. Manufactured by Finnish startup Oura the ring can collect temperature data continuously throughout the day and night allowing researchers to measure people's true temperature baselines and identify fever peaks more accurately. Fever is a leading symptom of COVID-19. Temperature varies not only from person to person but also for the same person at different times of the day according to