The NHS online symptom checker for coronavirus is too simplistic and may be causing the public to discount mild symptoms and underestimate their risk, say experts.
Across the globe governments and private companies have created online tools for their citizens to check whether their symptoms are likely to be coronavirus.
In the UK, the NHS online service is solely based on three Covid-19 symptoms: a high temperature, a cough or breathlessness. If a user says they have none of them, the system responds that “you’re unlikely to have coronavirus.”
This approach is in marked contrast with other governments. In France, the online tool asks everyone 23 questions – including whether an individual has a sore throat, aches and pains, fatigue or loss of smell and taste.
If a person responds that they do have these symptoms, even without a fever, cough or shortness of breath, they are told to “monitor your condition carefully” and limit contact with other people.
“Do not hesitate to contact your doctor if in doubt,” the online tool says. “Measure your temperature twice a day. Repeat this test if there is a new symptom to reassess the situation. Stay home until the symptoms go away, but watch for any worsening.”
The United States also has a more thorough symptom checker than the NHS – chatbot called ‘Clara’ created by the the Centre for Disease Control (CDC) and Microsoft’.
The tool asks users if they have a fever, shortness of breath or cough, but also if they are experiencing nausea or diarrhea, fatigue, muscle aches, a headache, a sore throat or a runny nose.
Although patients who have the latter set of symptoms are not told whether or not they might have Covid-19, they are advised to “stay at home and monitor your symptoms. Call your provider if you get worse.”
While the NHS symptom checker asks for a user’s gender, age and postcode, it does not warn about other symptoms or ask about underlying health conditions – creating the risk that users will be less cautious than they should be and spread the virus.
“Throughout the outbreak I have been incredibly bothered by the [UK’s] restricted case definition,” said Jonathan Ball, professor of molecular biology at the University of Nottingham.
“When you look at the medical reports describing how cases are presenting, particularly mild infections, coronavirus patients clearly have cold-like symptoms,” he added.
As the Telegraph previously noted, the NHS was advising for the first two full months of the crisis that “shortness of breath” was a necessary symptom of coronavirus.
This is despite the WHO making clear from the outset this was only the case with more serious forms of the illness.
Other nations have tended to follow the WHO’s more nuanced approach. Canada and Australia either ask individuals to stay at home or call a health care provider if they have a sore throat.
Meanwhile in South Korea the Centres for Disease Control has created a chatbot through KakaoTalk, one of the country’s most popular messaging services.
The symptoms flagged as indicating a coronavirus infection include fatigue, fever, coughing, pain, blocked nose, runny nose, sore throat or diarrhea. The service says that this list is based on information from the WHO and urges individuals with symptoms to call a doctor and get tested.
The country has been praised for rigorous and widespread testing, with every potential coronavirus patient checked.
Prof Ball said that this was the only way to confirm a coronavirus infection. “Nobody at any other time would try and do a differential diagnosis for a respiratory virus based on symptoms alone. Yet here we are with a new virus relying on that because we don’t have capacity to test.”
The WHO states that “common” coronavirus symptoms include fever, tiredness and dry cough. The UN agency also lists shortness of breath, aches and pains, a sore throat, diarrhoea, nausea or a runny nose on its website.
Paul Hunter, professor of medicine at the University of East Anglia, said the NHS online checker was based on a paper published in late February on the clinical characteristics of the coronavirus in China. But he said the issue for all health providers is that the symptoms are broad and cases can be extremely mild.
“The problem with all of the symptoms that are associated with Covid19 is that are associated with a whole range of other stuff too. But if you’ve got these classic symptoms of fever and cough then we can be pretty sure you have the coronavirus. So I think that’s a reasonable diagnostic”
Public Health England said that the NHS 111 symptom checker follows the case definition as set by the Chief Medical Officer, Professor Chris Witty.
Steve Powis, NHS England Chief Executive, said on Saturday: “On the question of symptoms, like many viruses that give infections of the upper respiratory tracts. There is a range of symptoms. The two commonest are by far cough and a fever and that is exactly why they are the two symptoms that we are asking people to self-isolate if they get those symptoms.”
The French system also asks patients about underlying health conditions – including diabetes, cardiovascular disease or cancer. An individual also inputs weight and height, allowing the system to calculate their body mass index (BMI) – there is evidence that being overweight can increase the risk of developing severe disease.
This article was originally published on Wednesday 25th March.
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