Academics found there was a surge in coronavirus cases roughly three to four weeks after a spike in online searches for the symptoms.
In New York, one of 15 regions examined in the study, searches for ‘diarrhoea’ almost doubled three weeks before the city’s cases of Covid-19 soared.
The NHS does not currently recognise diarrhoea as being a tell-tale sign of Covid-19, contradicting their colleagues in the US.
It says only a fever, a new cough and a loss of taste and smell are symptoms of the virus, meaning thousands of Britons who don’t experience those effects may fail to self-isolate and get tested during the early stages of their infection.
Scientists have already called for diarrhoea to be added to the list of symptoms for children in Britain, after their ability to spot the disease in youngsters rose from 76 to 97 per cent when it was included in the symptoms list.
Diarrhoea could be an early warning sign of coronavirus. A study found that searches for this rose before an outbreak of coronavirus was detected in their area
The ability to detect children who had coronavirus rose from 76 per cent to 97 per cent when stomach and gut pains were included with the official NHS symptoms, say researchers (stock)
What are the symptoms of coronavirus?
What the NHS says:
- A high temperature
- New continuous cough
- Loss of taste or smell
What other symptoms are there?
As many as 16 other symptoms of coronavirus have also been identified, although they are yet to be listed by the NHS.
The Center for Disease Control (CDC) in the US updated its list back in May to include these symptoms:
- Shortness of breath or difficulty breathing
- Muscle or body aches
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
The UK’s Covid symptom app says it has additional several further warning signs of the disease.
It has done this by asking more than 3.9 million people to report daily how they are feeling.
When they feel unwell they are asked to report the symptoms. Those that test positive for coronavirus then tell the app, allowing it to reveal less-well-known signs of the disease. It adds the following:
- Skin rash
- Abdominal pain
- Chest pain
- Hoarse voice
- Eye soreness
- Dizziness or light-headed
The study, carried out by Massachusetts General Hospital in Boston, used Google Trends to monitor digital queries for ‘diarrhoea’, ‘loss of appetite’ and ‘loss of smell’ made in 15 states between January 20 and April 20.
It revealed a correlation between searches for these terms and a rise in coronavirus cases almost a month later.
The five states with the strongest correlation were New York, New Jersey, California, Massachusetts and Illinois.
The research was published in the Journal Clinical Gastroenterology and Hepatology.
Writing in the study Dr Kyle Staller, a gastroenterologist at Massachusetts General Hospital, said: ‘Gastrointestinal symptoms appear to be a harbinger of Covid-19 infection.
‘Google Trends may be a valuable tool for predicting geographic hotspots of Covid-19 and other epidemic diseases that have gastrointestinal manifestations.’
UK health chiefs have been repeatedly accused of being behind the curve when it comes to fighting coronavirus for continuously refusing to list gut problems as symptoms of the disease.
The Centers for Disease Control and Prevention (CDC) in the US revised its website four months ago to include diarrhoea, alongside a runny or blocked nose, nausea and five others.
Professor Tim Spector, an epidemiologist at King’s College London, warned that the UK’s list of symptoms is still ‘too limited’ and has fallen behind other countries around the world.
Speaking to MailOnline, he said: ‘By only stating three symptoms we are failing to provide people with all the information they need to take action.’
His Covid Symptom Study app, where users enter in what symptoms they have when they are feeling unwell and whether they have tested positive for coronavirus, has identified 20 possible symptoms.
‘What our data has shown is that symptoms like headache and fatigue are more common than the classical symptoms,’ he said.
‘We also see children under 18 and adults over 65 presenting with different symptoms.’
The team behind the app is working directly with the Government, and hoping to get more symptoms added to the official list ‘soon’.
The limited number of recognised symptoms means that many possible infections may be missed in the early stages, increasing the risk that the disease could be spread to others as people don’t realise they may need a test and to self-isolate.
Scientists in Northern Ireland advised at the start of this month that vomiting, diarrhoea and stomach pains should be considered as symptoms of coronavirus in children.
The Centers for Disease Control and Prevention (CDC) now recognises 11 Covid-19 symptoms
The UK has been accused of missing ‘the majority’ of Covid-19 cases because it still only recognises three tell-tale signs of the infection (the NHS website, shown)
Dr Tom Waterfield at Queen’s University Belfast told the BBC: ‘We are finding that diarrhoea and vomiting is a symptom reported by some children and I think adding it to the list of known symptoms is worth considering.’
Dr Waterfield and other scientists studied 992 children, of whom 68 had coronavirus. They had an average age of 10 years.
By looking at children with fever, coughs and changes in smell or taste – the official Covid-19 symptoms – scientists correctly identified 76 per cent of children with the coronavirus.
But when they added children who had stomach problems this rose to 97 per cent – 33 out of the 34.
Dr Waterfield and colleagues wrote: ‘This study demonstrates that approximately half of children are asymptomatic when infected with SARS-CoV-2 and that current UK testing strategies will fail to diagnose the majority of paediatric infections.’
The NHS, like the majority of health bodies around the globe, initially recognised just two symptoms of coronavirus – a dry and persistent cough and a fever.
But a mountain of evidence emerged in the months after the initial outbreak in China showing the virus caused rarer symptoms.
Health bosses dug their heels in and refused to admit any new symptoms to their list despite mounting reports that loss of taste and smell should be included.
They finally caved-in in May, adding it to their list, but have since refused to recognise any additional symptoms of coronavirus.