‘Long colds’: People may experience prolonged symptoms weeks after a respiratory infection

Symptoms of respiratory illnesses such as common cold viruses, influenza, or pneumonia may last more than four weeks after the initial infection, according to new research.

Scientists from the Queen Mary University of London analysed data from more than 10,000 people to compare long-term symptoms of COVID-19 and other illnesses.

While long COVID is now a recognised affliction affecting millions, few studies have compared it to lasting symptoms following other acute respiratory illnesses. The findings were published in The Lancet’s eClinicalMedicine journal.

Researchers found that people may have ‘long cold’ symptoms such as coughing, stomach pain, and diarrhoea weeks after infection.

The people recovering from COVID-19, however, were more likely to experience light-headedness, dizziness, and problems with taste and smell.

“Our findings shine a light not only on the impact of long COVID on people’s lives, but also other respiratory infections. A lack of awareness—or even the lack of a common term —prevents both reporting and diagnosis of these conditions,” said lead author Giulia Vivaldi in a statement.

Another study, published in April this year, observed persistent symptoms in patients infected by influenza, calling it ‘long flu’.

‘Long colds’ difficult to diagnose

Researchers noticed that people suffering from long-term symptoms were more likely to be female, lower class, or have comorbidities.

Frontline workers were also statistically overrepresented, and the data showing that having a severe primary infection could be a risk factor.

“As research into long COVID continues, we need to take the opportunity to investigate and consider the lasting effects of other acute respiratory infections,” Vivaldi said.

She added that they are difficult to diagnose and treat because of a lack of diagnostic tests and the range of possible symptoms.

“The study is important in showing that recovery from acute respiratory infection (ARI) may be slow regardless of cause, that people should expect a slow return to normality and not expect to immediately return to full activities immediately after an ARI from whatever cause,” said Peter Openshaw, a professor of experimental medicine at Imperial College London, in a statement.

Openshaw wasn’t involved in the study and he cautioned that the term “long cold” should not belittle the very serious disability of long COVID that some suffer from.

Experts also noted the need “to ensure all people with ongoing symptoms can access the support they need” and avoid under-diagnosis.

The next step for researchers is to identify the underlying reasons why some people are more susceptible to suffer from long colds compared to others.