Long COVID: An Epidemic within the Pandemic

Coronavirus disease 2019 (COVID-19), a life-threatening infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in the Chinese city of Wuhan in late 2019 and has subsequently spread worldwide, reaching pandemic proportions [1]. At the time of writing (i.e., May 2023), COVID-19 has already caused nearly 7 million official deaths, according to World Health Organization (WHO) statistics [2]. Although the WHO COVID-19 emergency committee recently decided to no longer classify COVID-19 as an international public health emergency, SARS-CoV-2 infections and/or reinfections still cause a large number of deaths worldwide, with an excess mortality still estimated at approximately 10,000 deaths per day [3]. In addition to the still significant organic injuries that can develop during an acute SARS-CoV-2 infection, particularly in frail, old and unvaccinated individuals, there is now established evidence that the so-called post-viral syndrome (i.e., a common consequence of many viral infections encompassing a kaleidoscope of organic and psychiatric disorders) [4] is a fairly common sequela of COVID-19 in officially recovered patients, variously termed “post-COVID”, “long-haul COVID”, “long COVID” and so forth.