The Prevalence of SARS-CoV-2 in Autopsies Surrounding the Time of Pandemic Onset: A Retrospective Review of Cases

Abstract

Context.— The first case of COVID-19 in the United States was confirmed in January 2020. Initially, little was known about the epidemiology and clinical course of the disease, and diagnostic testing was limited in the United States until March/April 2020. Since then, many studies have speculated that SARS-CoV-2 may have preexisted undiagnosed outside China before the known outbreak. Objective.— To evaluate the prevalence of SARS-CoV-2 in adult autopsy cases performed just before and during the beginning of the pandemic at our institution, where autopsy was not performed on known COVID-19 cases. Design.— We included adult autopsies performed in our institution from June 1, 2019, to June 30, 2020. Cases were divided into groups based on the likelihood of cause of death being related to COVID-19, presence of a clinical respiratory illness, and histologic findings of pneumonia. Archived formalin-fixed, paraffin-embedded lung tissue of all COVID-possible cases and COVID-unlikely cases with pneumonia was tested for SARS-CoV-2 RNA, using Centers for Disease Control and Prevention 2019-nCoV quantitative real-time reverse transcription–polymerase chain reaction (qRT-PCR). Results.— Eighty-eight cases were identified, and among those, 42 (48%) were considered COVID-possible cause of death, with 24 of those 42 cases (57%) showing respiratory illness and/or pneumonia. COVID-19 as cause of death was considered unlikely in 46 of 88 cases (52%), with 34 of those 46 cases (74%) showing no respiratory illness or pneumonia. SARS-CoV-2 real-time reverse transcription–polymerase chain reaction was performed on a total of 49 cases, 42 COVID-possible and 7 COVID-unlikely with pneumonia, and all cases were negative (0 of 49). Conclusions.— Our data suggest that autopsied patients in our community who died between June 1, 2019, and June 30, 2020, without known COVID-19 were unlikely to have had subclinical and/or undiagnosed COVID-19 infection.