A recent paper published in the Journal of Infectious Diseases should set off an alarm about the lingering impacts of COVID-19 on the global workforce.

Biostatistics researchers at the University of Michigan School of Public Health conducted a meta-analysis of 41 studies around the world looking at "post COVID-19 condition", otherwise known as Long COVID, in hospitalized and nonhospitalized patients.

The global prevalence of post COVID-19 condition was estimated at 37 percent after 30 days, 25 percent at 60 days, 32 percent at 90 days, and 49 percent at 120 days.

They found that fatigue was the most common symptom followed by memory problems.

"This study finds post COVID-19 condition prevalence is substantial; the health effects of COVID-19 appear to be prolonged and can exert stress on the healthcare system," they wrote.

A meta-analysis is an examination of data from many independent studies on the same subject in order to detect trends in the research.

On a global basis, post COVID-19 condition prevalence was estimated at 43 percent over the entire period. It was 54 percent for those who had been hospitalized compared to 34 percent for those who were not admitted to hospital.

The meta-analysis found that post COVID-19 condition was more prevalent in women, at 49 percent, in comparison to men, at 37 percent.

The greatest prevalence, 51 percent, was in Asia, compared to 44 percent in Europe and 31 percent in North America.

"We defined post COVID-19 condition as having any symptoms, or at least one new or persisting symptom during the follow-up time," they stated. "Furthermore, the follow-up time of COVID-19 patients across studies was divided into the following four groups: symptoms at 28-30 days (labeled as 30 days), 60 days, 90 days, and 120 days after the index date.:

This definition diverges from that of the World Health Organization.

"Post COVID-19 condition occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms and that last for at least 2 months and cannot be explained by an alternative diagnosis," the WHO states on its website.

"Common symptoms include fatigue, shortness of breath, cognitive dysfunction but also others and generally have an impact on everyday functioning," the WHO definition continues. "Symptoms may be new onset following initial recovery from an acute COVID-19 episode or persist from the initial illness. Symptoms may also fluctuate or relapse over time."