The immunologic and virologic determinants of long COVID

Coronavirus infection has been confirmed in over 157 million people worldwide and over 4 million people in the UK. Initially, there was understandable focus on the care of patients hospitalized with severe disease, but it has subsequently been recognized that many individuals managed their symptoms in the community during the acute phase of COVID-19. The long-term effects of infection in both groups are now becoming apparent. Long COVID describes a broad range of symptoms that persist 12 weeks after acute infection with SARS-CoV-2. Symptoms are diverse and commonly include fatigue, breathlessness, cognitive impairment ("brain fog"), chest pain, palpitations, and persistent disturbances in smell and taste. Data from the Office for National Statistics suggest that over a million people in the suffer with long COVID in the UK. The potential economic impact and anticipated burden faced by the NHS as a consequence of long COVID has been acknowledged more recently, and a spotlight has been focused on the need for research into the multisystem effects of the condition to inform the future development of diagnostics and therapeutic strategies. Published studies have emphasized the importance of immune responses during acute COVID19. However, little is known about the role of the immune system in long COVID. Our study aims to investigate the hypothesis that overactive or maladaptive immune responses drive ongoing systemic inflammation and clinical symptoms in patients with long COVID.