Long-COVID: How Common Is It?

I often find that as the pandemic of COVID-19 has progressed and interest has waned in response and/or interventions, I’m having to remind people that the acute piece of an infectious disease isn’t all you get.

It many ways, we’re just starting to more broadly acknowledge the chronic conditions that are a result of an acute infection. In terms of COVID-19, long COVID has been a real piece that we’re just starting to dig into.

How long do these symptoms last? How frequently do they occur and is there any association with disease severity? There are countless examples of people infected with COVID-19 in early 2020, still experiencing symptoms of long COVID. While the narrative around COVID has changed with so many calling it “another flu”, the simple truth is that the long-lasting symptoms of COVID are something we should all be worried about, even if the acute infection is mild.

A new research study was just released in JAMA via the Global Burden of Disease Long COVID Collaborators in which the research team sought to estimate what proportion, globally, people with symptomatic COVID-19 in 2020 and 2021, experienced persistent fatigue, cognitive, and respiratory symptom clusters. Utilizing a bayesian meta-regression and pooling observational analysis, 54 studies and 2 medical record databases were utilized to assess 1.2 million individuals across 22 countries who had experienced symptomatic COVID infections during the first two years of the pandemic. Cohort studies utilized were from countries such as Austria, Germany, Iran, Italy, and the United States, whereas participant data was pulled from 44 studies and the two electronic medical record databases previously mentioned were from US healthcare systems.

How did they measure this? Assessing the proportion of individuals who self-reported at least one of the three Long COVID clusters (persistent fatigue with bodily pain or mood swings; cognitive problems; or persistent respiratory problems) three months after their acute SARS-CoV-2 infection. Researchers assessed those individuals who were hospitalized vs non-hospitalized, those 20 years or older, by sex, etc.

So, what did they find? Well, the proportion of people with Long COVID symptom clusters was startling. The research team noted that, “in the modeled estimates, 6.2% (95% uncertainty interval [UI], 2.4%-13.3%) of individuals who had symptomatic SARS-CoV-2 infection experienced at least 1 of the 3 Long COVID symptom clusters in 2020 and 2021, including 3.2% (95% UI, 0.6%-10.0%) for persistent fatigue with bodily pain or mood swings, 3.7% (95% UI, 0.9%-9.6%) for ongoing respiratory problems, and 2.2% (95% UI, 0.3%-7.6%) for cognitive problems after adjusting for health status before COVID-19, comprising an estimated 51.0% (95% UI, 16.9%-92.4%), 60.4% (95% UI, 18.9%-89.1%), and 35.4% (95% UI, 9.4%-75.1%), respectively, of Long COVID cases.

The Long COVID symptom clusters were more common in women aged 20 years or older (10.6% [95% UI, 4.3%-22.2%]) 3 months after symptomatic SARS-CoV-2 infection than in men aged 20 years or older (5.4% [95% UI, 2.2%-11.7%]).” The estimated mean duration of these symptoms was around 9 months in the hospitalized group versus 4 months in the non-hospitalized group. For those with Long COVID symptoms 3 months after their acute infection, 15.1% continued to experience these symptoms at a year.

Ultimately, this underscores the considerable impact that COVID has on individuals, how long such symptoms of Long COVID can last, and a desperate need to address the implications of these issues for individuals.