While weariness, a sore throat, and headaches are well-known symptoms of Covid, there is a new symptom that has been reported by many people.
The ZOE Health Study app found that diarrhoea was the most often reported symptom of Covid among vaccinated British citizens.
There was an increase in the number of reports of this symptom in January 2022, and part of that increase seems to be attributable to the Omicron form of Covid-19.
There seems to be a "wave of other non-Covid tummy illnesses going around also," the ZOE team noted.
According to the research team, diarrhoea may be an early indication of the virus.
Appearing as early as the first day of infection and worsening over the course of the week.