Introduction
The recent emergence and rapid global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting coronavirus disease 2019 (COVID-19) poses an unprecedented health crisis that was declared a pandemic by the World Health Organization (WHO) on March 11, 2020. The origin of SARS-CoV-2 was traced to the city of Wuhan in the province of Hubei, China, where a cluster of viral pneumonia cases was first detected, many in connection with the Huanan Seafood Wholesale Market. China reported this outbreak to the WHO on December 31, 2019 and soon after identified the causative pathogen as a betacoronavirus with high sequence homology to bat coronaviruses (CoVs) using angiotensin-converting enzyme 2 (ACE2) receptor as the dominant mechanism of cell entry (Lu et al., 2020a, Wan et al., 2020b). Following a likely zoonotic spillover, human-to-human transmission events were confirmed with clinical presentations ranging from no symptoms to mild fever, cough, and dyspnea to cytokine storm, respiratory failure, and death. SARS-CoV-2 is also closely related to SARS (retrospectively named SARS-CoV-1) and Middle Eastern respiratory syndrome (MERS) CoVs, causing zoonotic epidemic and local outbreaks in 2003 and 2012, respectively (de Wit et al., 2016). While SARS-CoV-2 is not as lethal as SARS-CoV-1 or MERS-CoV (Fauci et al., 2020), the considerable spread of the current pandemic has brought tremendous pressure and disastrous consequences for public health and medical systems worldwide.
The scientific response to the crisis has been extraordinary, with a plethora of COVID-19 studies posted in preprint servers in an attempt to rapidly unravel the pathogenesis of COVID-19 and potential therapeutic strategies. In response, trainees and faculty members of the Precision Immunology Institute at the Icahn School of Medicine at Mount Sinai (PrIISM) have initiated an institutional effort to critically review the preprint literature (Vabret et al., 2020), together with peer-reviewed articles published in traditional journals, and summarize the current state of science on the fast-evolving field of COVID-19 immunology. We thematically focus on the innate and adaptive immune responses to SARS-CoV-2 and related CoVs, clinical studies and prognostic laboratory correlates, current therapeutic strategies, prospective clinical trials, and vaccine approaches.