Scientists say “long colds” may exist and are just as common as long Covid.
Researchers at Queen Mary University of London found people experience long-term symptoms – or long colds – after respiratory infections that test negative for Covid-19.
Some of the most common symptoms of long cold were coughing, stomach pain and diarrhoea lasting for more than four weeks after infection.
The research, published in The Lancet’s EClinicalMedicine journal, suggests some – though not all – people may suffer long-term effects from colds, flu or pneumonia.
“Our findings suggest that there may be long-lasting health impactsfrom other respiratory infections that are going unrecognised, although we do not yet have evidence that these symptoms have a similar duration to long Covid,” the researchers said.
These ‘long’ infections are so difficult to diagnose and treat primarily because of a lack of diagnostic tests and there being so many possible symptoms— Giulia Vivaldi, Queen Mary University
For the study, experts looked at data from 10,203 people taking part in the Covidence UK study into coronavirus in the population.
At the time of this analysis, some 1,343 had suffered a Covid infection and 472 a respiratory infection that tested negative for Covid.
The results showed that 22% of people with Covid-19 suffered prolonged symptoms after infection, as did 22% of those who had an infection that was not Covid, Professor Adrian Martineau, from Queen Mary University of London, who worked on the study, told the PA news agency.
He said there was a “similar risk of prolonged symptoms” irrespective of whether it was caused by Covid or non-Covid infection.
Prof Martineau said people with Covid in the study were more likely to suffer taste and smell problems – known symptoms of coronavirus – and light-headedness or dizziness than those without.
They also suffered heart palpitations, sweating and hair loss.
Meanwhile, those in the non-Covid group were more likely to have a cough or a hoarse voice than people with Covid, something that was surprising given a cough is often associated with Covid.
Both groups suffered breathlessness and fatigue.
The study also suggested that the more serious a bout of illness, the greater the chance of having long-term symptoms.
However, the experts said more studies are needed on why some people suffer while others do not.
Lead author Giulia Vivaldi from Queen Mary University of London, said: “Our findings shine a light not only on the impact of long Covid on people’s lives, but also other respiratory infections.
Ongoing research into the long-term effects of Covid-19 and other acute respiratory infections is important because it can help us to get to the root of why some people experience more prolonged symptoms than others— Professor Adrian Martineau, Queen Mary University
“A lack of awareness – or even the lack of a common term – prevents both reporting and diagnosis of these conditions.
“As research into long Covid continues, we need to take the opportunity to investigate and consider the lasting effects of other acute respiratory infections.
“These ‘long’ infections are so difficult to diagnose and treat primarily because of a lack of diagnostic tests and there being so many possible symptoms.
“There have been more than 200 (symptoms) investigated for long Covid alone.”
The study looked at people’s symptoms after their initial infection, using standardised questionnaires.
The longest time from initial infection to reports of ongoing symptoms was 37 weeks for non-Covid infections and 64 weeks for Covid-19.
The non-Covid group all tested negative for Covid, while those in the Covid group either tested positive or had classic coronavirus symptoms but developed the infection at a time when testing was not routinely available.
To ensure the results were robust, Prof Martineau said further analysis of the data had been carried out.
This was of those who tested positive and those who did not, and the findings were the same as for the larger group of people in the study.
Prof Martineau said: “Our findings may chime with the experience of people who have struggled with prolonged symptoms after having a respiratory infection despite testing negative for Covid-19 on a nose or throat swab.
“Ongoing research into the long-term effects of Covid-19 and other acute respiratory infections is important because it can help us to get to the root of why some people experience more prolonged symptoms than others.
“Ultimately, this could help us to identify the most appropriate form of treatment and care for affected people.”
Dr David Strain, clinical senior lecturer and honorary consultant at the University of Exeter, welcomed the study, adding the researchers had “demonstrated, at least in the short term, persistence of symptoms can be troubling not just after Covid-19 but after many other infections”.
He said this was not a new phenomenon, citing the Spanish flu epidemic in 1918-20 as leaving many people with post-viral illness.
He said the research will bring into focus the “urgent need for further research into post-viral syndromes”, what causes them and the need for treatments.
Data suggests around 1.9m people in the UK are living with long Covid.
