342A - Severe Acute Respiratory Syndrome Coronavirus 2

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the seventh known coronavirus to infect humans, causes coronavirus disease 2019 (COVID-19) and has precipitated a worldwide pandemic unlike any seen since the influenza pandemic of 1918. The virus is spread predominantly by respiratory droplets and aerosols, and, to a lesser degree, via contaminated surfaces. After an incubation period averaging 5 days but sometimes as long as 12 days, symptoms include fever, cough, shortness of breath, changes in taste or smell, fatigue, myalgias, gastrointestinal complaints, chills, headache, and sore throat. Patients may develop severe coughing, hypoxia, and acute respiratory distress. The diagnosis is based on detecting SARS-CoV-2 RNA by polymerase chain reaction (PCR) assays, usually on nasopharyngeal swabs. About 20% of symptomatic patients are sick enough to require hospitalization. Steroids (dexamethasone or high-dose hydrocortisone) can reduce death by about one-third in mechanically ventilated COVID-19 patients and by about 20% in nonventilated patients who are receiving supplemental oxygen. Overall, remdesivir appears to reduce the median recovery time from about 15 days to about 11 days, but it may not reduce mortality. Interleukin-6 inhibition can reduce disease severity in hospitalized patients and mortality in severely ill patients who require oxygen therapy. Monoclonal antibody therapy may be beneficial in outpatients with mild-to-moderate disease but does not appear to benefit hospitalized patients. Convalescent plasma can reduce the viral load, and it improved the percentage of patients discharged alive or improved at 28 days in one of two trials. The cornerstones of prevention are respiratory precautions (e.g., masks) and distancing. In a Wuhan series, the reported case-fatality rate was 2.3%. The infection fatality rate (deaths per estimated number of infections whether diagnosed or not) in the United States was initially about 1.3%, with mortality rates much higher in patients older than age 70 years. More recently, U.S. infection mortality rates appear to have declined by 30 to 50%, and the estimated infection mortality rate in Iceland is 0.3%. More than 95% of infected patients appear to develop antibodies, which usually persist for at least 6 months and are about 80–85% protective against recurrent infection. The best vaccines have been able to provide 90% or greater protection. The severity and duration of long-term sequelae among survivors are uncertain.