Post-COVID-19 Syndrome: Persistent Symptoms at the Post-Viral Stage of the Disease. A Systematic Review of Current Data

This systematic review from May 2021 analyzed 145 studies to understand the long-term symptoms, often referred to as "post-COVID syndrome" or "long-haul COVID-19", in patients who had recovered from the acute phase of COVID-19. The studies reported that 20.70% of long-term symptoms were related to abnormal lung functions, 24.13% were related to neurologic complaints and olfactory dysfunctions, and 55.17% were related to widespread symptoms, primarily chronic fatigue and pain. The review found that a significant number of patients experienced persistent symptoms, including fatigue, dyspnea, joint pain, chest pain, cognitive disturbances, and hair loss, even 90 days and beyond after the initial infection. The severity of persistent symptoms often correlated with the severity of the initial infection. However, even mild cases reported long-term symptoms. The review concluded that post-COVID-19 syndrome is a significant issue that requires further research and effective management strategies.