Half of COVID-19 patients report symptoms after 12 weeks, health agency review finds

A new review by the Public Health Agency of Canada says more than half of COVID-19 patients might suffer from "post-COVID syndrome" for more than three months after testing positive.

The review looked at more than two dozen studies from around the world which asked confirmed COVID-19 patients to report at least one long-term symptom.

Initial findings suggest more than eight in 10 people had at least one long-term symptom four to 12 weeks after diagnosis, and more than half reported lingering symptoms after 12 weeks.

Fatigue, pain, shortness of breath and sleep disturbances were the most common issues, followed by anxiety, cough and hair loss.

Chief Public Health Officer Dr. Theresa Tam said in a statement that while most people will recover fully from COVID-19 within weeks, what is known as "long COVID" can affect people across all age groups — no matter how sick they got at first.

The study notes some potential weaknesses in the data because of self-reporting of conditions, a bias in the selection of patients involved in the studies, and a lack of knowledge of what pre-existing conditions patients might have had before they got COVID-19.