Acute SARS-CoV-2 infection.

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a respiratory pathogen that emerged in December 2019 and caused a global pandemic by March 2020, with >7 million deaths due to coronavirus disease 2019 (COVID-19) globally as of September 2025. The clinical syndrome of COVID-19 ranges from asymptomatic infection to severe disease with pneumonia and death. SARS-CoV-2 variant type, inoculum, previous exposure and host factors influence the clinical trajectory. Identification of key structural proteins of SARS-CoV-2 and insights into the pathophysiology of the immune response to infection led to the development of effective preventive (vaccines and monoclonal antibodies) and therapeutic (antivirals and immunomodulatory agents) agents. Antiviral agents, such as remdesivir and nirmatrelvir-ritonavir, inhibit viral replication and immunomodulatory agents, such as tocilizumab and baricitinib, act to reduce a dysregulated immune response to SARS-CoV-2. The pandemic had economic and socio-cultural consequences that affected the quality of life and overall life expectancy of individuals. As the emergency phase of the pandemic concludes, robust monitoring and surveillance systems must be sustained and research to improve vaccines and therapeutics must continue to maintain control of SARS-CoV-2 in the population and be prepared for emerging pathogens with pandemic potential.