Long COVID: what is known and what gaps need to be addressed

Abstract

Introduction: Long COVID is a chronic condition that follows after acute COVID-19 and is characterized by a wide range of persistent, cyclic symptoms. Sources of data: PubMed search for publications featuring 'Long COVID' or 'post-acute sequelae of COVID-19'. Areas of agreement: Long COVID occurs frequently post-acute COVID-19, with a majority of people experiencing at least one symptom (such as cough, fatigue, myalgia, anosmia and dyspnoea) 4 weeks after infection. Areas of controversy: The specific symptoms and the minimum duration of symptoms required to be defined as Long COVID. Growing points: There is a consistent reduction in Long COVID incidence amongst vaccinated individuals, although the extent of this effect remains unclear. Areas timely for developing research: There is an urgent need to understand the causes of Long COVID, especially extreme fatigue more than 6 months after infection. We must understand who is at risk and whether reinfections similarly risk Long COVID.