The UK is likely missing between 50,000-70,000 Covid-19 cases because it has not updated its list of coronavirus symptoms, a professor who leads the Kings College London Covid Symptom Tracker app said Monday.

Professor Tim Spector told BBC Radio 4’s Today programme that his team’s app has listed “about 14 symptoms which [they] know are related to having a positive swab test and these are not being picked up by the NHS.” These include symptoms such as the loss of smell and taste and severe muscle pain and fatigue.

Professor Spector said the app is the “largest source of data” in the UK, with more than 1.5 million signed up to offer information about their response to the virus.

Citizens in the dark about symptoms: He said that UK citizens are not aware of the full spectrum of symptoms due to the lack of testing and the advice to only self-isolate if they have a high-fever or cough.

“There’s no point telling people to be alert if they don’t know the symptoms,” he added.

Other countries expand lists: Professor Spector noted 17 other countries, the WHO, the EU and even the CDC altered and expanded their list of symptoms a few weeks ago.

Since the UK began testing, 243,695 people have tested positive for the virus, according to the latest figures from the Department of Health and Social Care.

Spector advised that “Public Health England … get in line with the rest of the world and make people more aware.”

He estimated that there are 100,000 cases of infected people in the UK at present and stressed that “there are still people out there who can infect others and we do have to be very vigilant,” as some parts of the UK begin to ease their lockdown.