Vivaldi et al have presented a very well conducted prospective review of residual symptoms after Covid 19, and after other non-Covid respiratory infections.  They demonstrated, at least in the short term, persistence of symptoms can be troubling not just after COVID-19 but after many other infections.

Whilst in the first to explore this prospectively, this is not a new phenomenon.  Indeed, the Spanish flu epidemic in 1918-20 left many individuals with Encephalitis Lethargica that took decades to resolve (This was the subject matter for the Oliver Sacks book Awakenings or depending on the audience the Robert De Niro and Robin Williams film).  The concept of post viral illness is also well established.  Today in the UK, approximately 280,000 people are living with Myalgic Encephalomyelitis (ME, otherwise known as Chronic Fatigue Syndrome) many of whom report a rather benign initial viral illness as the trigger.

A limitation of this study is that it only looks at symptoms at a single timepoints.  Whereas those involved in the COVIDENCE trial report symptoms lasting beyond 3 months and up to 2 years, many of those with ME/CFS have experienced their symptoms for decades.  In the absence of an understanding of the mechanisms or any diagnostic tests they have faced unprecedented stigma from society.  It is hoped that it will not be the legacy of today’s healthcare system, to leave these young and previously fit people behind.  This study will bring into focus the urgent need for further research into post viral syndromes, the risk factors and therefore routes to risk mitigation, diagnostic tests and potential treatments to help the quarter of a million plus in the UK and Millions worldwide who are suffering this terrible condition.

The study supports previous findings that long-term symptoms are common after respiratory infections in general, not just following COVID-19.  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.  A strength of the study is its prospective, UK population-based nature. A weakness is the relatively small number of non-COVID-19 infection cases.