Scientists discover a new form of chronic illness and you may already suffer from it

According to the Santé Publique France website, 2 million people were suffering from a post-COVID-19 condition at the end of 2022. Worldwide, the number is estimated at 10 million. Over 200 symptoms of long COVID have been studied, the most common being fatigue, shortness of breath and cognitive impairment. But COVID may not be the only one to cause long-lasting symptoms.

Discover our latest podcast

After the long COVID, the 'long cold'

In an experiment conducted by a team of researchers from Queen Mary University of London led by Giulia Vivaldi, 10,000 people reported 16 symptoms commonly observed in cases of long-lasting acute respiratory infections, such as fatigue, shortness of breath, pain and dizziness.

Giulia Vivaldi and colleagues then compared the frequency of these symptoms in three groups: those who had tested positive for COVID, those who had reported another acute respiratory infection (but tested negative for COVID) and those who had reported no infection.

We focused on long-term symptoms, including only those who had been infected more than four weeks previously. We also took into account people's general state of health prior to infection, and whether they had any respiratory problems.

Experience has shown that this type of symptom is more frequent in people who have already suffered from COVID or a respiratory infection without COVID, than in those who have not.

In other words, our results suggest the existence of a "long cold": lasting health effects from other respiratory infections, such as colds, flu or pneumonia, that are not currently recognized.

Among the most common symptoms of the long cold are coughing, stomach pains and diarrhea. These symptoms were reported on average 11 weeks after infection.

While a severe initial infection seems to increase the risk of long-term symptoms, researchers still don't understand why some people suffer prolonged symptoms while others do not.

'Long Cold': A Hidden Form of Chronic Sickness Has Just Been Identified https://t.co/H9P4YQRpqZ
— ScienceAlert (@ScienceAlert) October 15, 2023

Significant differences

Further refining their research, Giulia Vivaldi and her colleagues discovered significant differences in the symptoms reported by the two groups: indeed, people recovering from COVID were more likely to suffer from dizziness or vertigo and problems with taste and smell.

These findings highlight not only the impact of long COVID on people's lives, but also that of other respiratory infections. The lack of a common term, such as 'long cold' or 'long flu', hinders both reporting and diagnosis of these infections. And people who do report their long cold may still find it difficult to get a diagnosis, due to the wide range of symptoms and lack of diagnostic tests.

The persistence of symptoms after a respiratory infection is not a new phenomenon: studies carried out on survivors of two epidemics - the Severe Acute Respiratory Syndrome (Sars) pandemic and the Middle East Respiratory Syndrome (Mers) epidemic - revealed long-term repercussions on lung function, quality of life and mental health. In addition, some people hospitalized for influenza A experienced respiratory and psychological problems for at least two years after discharge from hospital. Giulia Vivaldi explains:

However, most research to date has focused on people with severe illness, often serious enough to require hospitalization. Little is known about the long-term effects of respiratory infections in people whose acute episode of illness is less severe.

By demanding recognition and publicizing their condition, long COVID sufferers have also put post-infectious syndromes in the spotlight.