How Common Is Long COVID? This New Study Hints at the Answer.

New research is adding to the growing body of data that points to long COVID as an all-too-common health issue. In a study from Denmark’s State Serum Institute (SSI), a government public health and research institution, just over 53% of people who tested positive for COVID-19 were still experiencing concentration difficulties, sleep issues, or physical exhaustion six to 12 months after originally testing positive. “New diagnoses of anxiety or depression were also more common among test-positives,” researchers said. 

Worth noting: The study, published February 28, is a pre-print that hasn’t been peer-reviewed yet, so it’s not possible to point to these results as confirmed proof of how common long COVID may be. Still, the findings are pretty notable. In the nationwide survey conducted between September 2020 and April 2021, 152,880 individuals aged 15 years or older were questioned about their symptoms, mental and physical health, lifestyle, and sick leave. The survey questioned people who had tested positive for COVID-19 as well as those who did not. For those who had COVID-19, their responses were recorded six, nine, or 12 months after diagnosis. 

In addition to the 53% finding, the research also found that the long-term symptoms were so severe that many people were unable to work; among the people who tested positive, 12% took sick leave sometime in between one month after initially testing positive and filling out the survey, compared with only 7% of people who hadn’t gotten COVID. Researchers concluded that long COVID symptoms appeared to be “significant” in the Danish population and believed the results to be “generalizable to other comparable populations.”

“Long COVID” is a term that describes persistent, prolonged, and potentially wide-ranging symptoms following a COVID-19 infection. These symptoms can last for months and can be mild, debilitating, or somewhere in between. According to the National Institutes of Health, these long-lasting symptoms can include fatigue, shortness of breath, sleep disorders, fever, gastrointestinal issues, anxiety, depression, and brain fog (when thinking becomes sluggish or muddled, similar to the way it does when someone’s exhausted or fighting the flu). “Long COVID has a serious impact on people’s ability to go back to work or have a social life. It affects their mental health and may have significant economic consequences for them, their families, and for society,” says the World Health Organization.

In February 2021, Congress pledged $1.15 billion over a four-year period to fund research into long COVID. Other countries around the world have also funded similar research, with the UK government pledging £18.5 million to investigate the causes, symptoms, and potential treatment of long COVID. But it will take time for those investments to deliver concrete new insights or recommendations when it comes to dealing with long COVID. 

For many people, grappling with long COVID feels like being thrown into the great unknown. So while the Danish study is yet to be peer-reviewed, it comes at a crucial time when many people are desperate to understand how long COVID might affect their health and daily functioning, and whether treatment is a viable option. In the meantime, getting vaccinated and boosted aren’t foolproof ways to protect yourself and others against COVID-19. But they remain the best defenses against getting COVID—and getting long COVID—that we have so far.