‘Long colds’ with similar respiratory impact as long Covid may be an ‘underestimated’ issue, a new study has concluded.

By analysing 16 potential long Covid symptoms in participants from a UK population-based study, researchers have found that a previous Covid infection was ‘associated with increased prevalence and severity of a wide range of symptoms’.

In particular, participants with a previous Covid infection had increased odds of problems with taste or smell and lightheadedness or dizziness compared with participants with previous non-Covid acute respiratory infections (ARIs).

However, they also found ‘increased burden of many symptoms’ among those who had non-Covid ARIs when compared with those with no previous infections.

The authors therefore suggested there could be ‘long-lasting health impacts from other respiratory infections that are going unrecognised’.

Using the COVIDENCE UK study, the researchers looked at data reported between January and February 2021 by over 10,000 participants who were unvaccinated against Covid.

Their findings said: ‘Participants with SARS-CoV-2 infection had increased odds of problems with taste/smell (odds ratio 19.74, 95% CI 10.53–37.00) and lightheadedness or dizziness (1.74, 1.18–2.56) compared with participants with non-COVID-19 ARIs.’

But for other symptoms, there was ‘little difference’ between those with previous Covid infections and those with other infections.

While the researchers suggested that long-term symptoms following ARIs could be similar to long Covid, they highlighted that their study does not show whether these symptoms have a similar duration.

The findings also indicated that coughing, problems with taste or smell and dyspnoea may be the first symptoms to show improvement following a Covid infection, since there was a lower symptom burden among participants who had been infected more than 12 weeks prior.

Both long Covid and post-ARI symptoms are likely under-reported, and for the latter, an ‘alternative diagnosis’ may be needed, according to the authors.

They said: ‘Importantly, less than a quarter of our participants with previous SARS-CoV-2 infection had ever reported long COVID—including half of participants with the most severe symptoms—suggesting that some people with ongoing symptoms may not be ascribing these symptoms to the infection, or may not consider their symptoms serious enough to qualify as long COVID.

‘This could exacerbate under-reporting of the condition, likely impacting the healthcare resources made available to people with long-term sequelae.

‘A lack of awareness of post-acute sequelae of other ARIs—or even the lack of a common term, like “long Covid”—is likely to contribute to under-reporting as well.’

The authors highlighted the need for future research which will enable diagnosis of both long Covid and other post-ARI symptoms so that all patients get the support they need.

Professor Paul Harrison, professor of psychiatry at the University of Oxford, said the study ‘supports previous findings that long-term symptoms are common after respiratory infections in general’ and not just after Covid.

He added: ‘However, Covid-19 infection was associated with a higher risk of several complaints, including memory problems, suggesting that ‘brain fog’ may be particularly related to the SARS-CoV-2 virus.’

Professor Peter Openshaw, professor of experimental medicine at Imperial College London, said: ‘The study is important in showing that recovery from 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.

‘The study does not show how many of those suffering from ARI go on to develop longer term debility.’

Research earlier this year suggested that for most patients with long Covid after an initial mild infection, symptoms may linger for several months but will resolve within a year. 

This article first appeared on our sister publication Pulse.