COVID-19 and its long-term sequelae: what do we know in 2023?

Abstract

Post‑viral syndrome is a well‑known medical condition characterized by different levels of physical, cognitive, and emotional impairment that may persist with fluctuating severity after recovering from an acute viral infection. Unsurprisingly, COVID‑19 may also be accompanied by medium- and long‑term clinical sequelae after recovering from a SARS‑CoV‑2 infection. Although many clinical definitions have been provided, "long‑COVID" can be defined as a condition occurring in patients with a history of SARS‑CoV‑2 infection, developing 3 months from the symptoms onset, persisting for at least 2 months, and not explained by alternative diagnoses. According to recent global analyses, the cumulative prevalence of long‑COVID seems to range between 9% and 63%, and is up to 6‑fold higher than that of similar postviral infection conditions. Long‑COVID primarily encompasses the presence of at least 1 symptom, such as fatigue, dyspnea, cognitive impairment / brain fog, postexertional malaise, memory issues, musculoskeletal pain / spasms, cough, sleep disturbances, tachycardia / palpitations, altered smell / taste perception, headache, chest pain, and depression. The most important demographic and clinical predictors to date are female sex, older age, cigarette smoking, pre‑existing medical conditions, lack of COVID‑19 vaccination, infection with pre‑Omicron SARS‑CoV‑2 variants, number of acute phase symptoms, viral load, severe / critical COVID‑19 illness, as well as invasive mechanical ventilation. Concerning the care for long‑COVID patients, the greatest challenge is the fact that this syndrome cannot be considered a single clinical entity, and thus it needs an integrated multidisciplinary management, specifically tailored to the type and severity of symptoms.