COVID-2019 fundamentals

Background. A novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified at the end of 2019. The disease caused by SARS-CoV-2 was named COVID-19. The main purpose of this review was to provide an overview of SARS-CoV-2. Methods. The authors searched the MEDLINE database for clinical studies related to virus characteristics, pathogenesis, diagnosis, transmission mechanisms, and treatment options. Results. As of January 27, 2021, the number of infected people and deaths associated with COVID-19 worldwide were approximately 100 million and 2 million, respectively. The manifestations of COVID-19 are variable, and the severity is affected by age and preexisting medical conditions. Children and adolescents are usually asymptomatic or have mild symptoms. Older adults, in comparison, may experience severe illness and have disproportionally elevated mortality. Among those who survive, some may experience enduring deficits. The viral load is particularly elevated in saliva and oropharynx, which constitute potential sources of infection. The diagnosis of the disease may be confounded by factors related to the replicating cycle of the virus, viral load, and sensitivity of the diagnostic method used. As of January 2021, COVID-19 has no cure but can be prevented. Its treatment is based on supportive care along with antiviral medications and monoclonal antibodies. In severe cases with multiorgan involvement, mechanical ventilation, dialysis, and hemodynamic support may be necessary. Conclusions. COVID-19 is a transmittable disease with a variable course. A substantial number of patients, particularly children, remain asymptomatic. Important advances have been made in the development of new treatments. However, the mortality in vulnerable populations remains elevated.