He told Sky News: “We have been saying since last Spring that the range of symptoms should be expanded.
“This has been clear from people reporting on our app, where over twenty symptoms of Covid are linked.
“30 percent of people who have a positive PCR test do not have those three classic symptoms.
“This is particularly true in the first three days of the illness when it is most infectious.”
He continued: “I understand why we didn’t do it last Spring because we didn’t have a testing process and it would have crashed the system.
“But now we have a fantastic testing system which is able to do more than 600,000 tests a day. This is time to do that and add those symptoms.
“We could reduce infections by 30 percent because these people would be told to stay at home.
“It is a real risk that we are ignoring.”
He also said more research was needed on whether the new variants of Covid cause different symptoms.
Professor Spector added that around 330,000, who have had a first vaccine dose and logged this using the app, show “very low levels of side-effects”.
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