A new study across 13 middle- and high-income countries reveals that 25% of patients reported symptoms of long Covid after symptomatic COVID-19.

Among the 25.1% of participants who said they experienced long-Covid symptoms, 12.8% reported sleeping disorders, 9.8% reported joint pain, 8.7% had fatigue, and 8.1% noted headaches. Almost a third of participants (29.8%) from lower middle-income countries said they had long Covid, compared with 14.4% in high-income countries.

Long Covid was defined as the presence of patient-reported symptoms 180 days after COVID-19, the authors said. The study was done by BMJ Global Health, an open access, peer-reviewed journal publishing research on all aspects of global health.

A second study published in BMC Public Health showed that, among 3,693 COVID-19 patients in China, 30.2% reported at least one persistent long-Covid symptom, and 10.7% noted symptoms affecting daily life.

The highest long-Covid prevalence was seen in patients with Arab/North African ethnicity (36.1%),  hospitalized patients were also at increased risk. The BMJ Global Health report suggests that the burden to health and healthcare-related costs may fall disproportionately on countries with the least capacity to carry them.

“Our results thus suggest that the burden to health and healthcare-related costs may fall disproportionately on countries with the least capacity to carry them, and most frequently affect individuals that may be under-represented in clinical trials of interventions aimed to combat long Covid,” the authors wrote.

Older age and re-infection is tied to higher risks of symptoms of long Covid. In the second study, people with COVID-19 were asked to complete a survey on symptoms 180 days after infection in March 2023 through June 2023.

Older age, female sex, and Covid re-infection were all associated with increased risk for self-reported long Covid. Those who reported more than three vaccine doses proved to be a protective factor. 

In the U.S., approximately 8.4% of adults report having experienced long Covid at some point, with 3.6% currently experiencing it and 2.3% currently having activity-limiting long Covid. A recent Yale-led study also found that up to 14% of long Covid patients surveyed had not returned to work three months after getting sick, according to Yale Medicine. Additionally, research indicates that nearly one in ten long Covid patients has also been impacted by the condition.