A new study finds the risks of developing long COVID declined over the first two years of the pandemic. But unvaccinated adults were more than twice as likely to get long COVID compared with those who were vaccinated.

The intense scientific effort that long COVID sparked has resulted in more than 24,000 scientific publications, making it the most researched health condition in any four years of recorded human history.

Long COVID is a term that describes the constellation of long-term health effects caused by infection with the SARS-CoV-2 virus. These range from persistent respiratory symptoms, such as shortness of breath, to debilitating fatigue or brain fog that limits people’s ability to work, and conditions such as heart failure and diabetes, which are known to last a lifetime.