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SARS-CoV-2 surveillance in decedents in a large, urban medical examiner’s office

Our take —

This study, available as a preprint and not yet peer reviewed, described how the Wayne County Medical Examiner office (WCMEO) in Michigan implemented a surveillance strategy testing 821 decedents (i.e. deceased persons) for SARS-CoV-2 infection. Testing took place from March 16 to July 10, 2020 through nasopharyngeal swabs. Overall, 8.8% tested positive for SARS-CoV-2, and Black race and older age (above 40 years in the study) were associated with a positive test result. Among suspected cases, 20% tested positive, while among randomly selected cases not suspected to be associated with COVID-19, 5% tested positive. As testing decedents in a medical examiner’s office may be a means to supplement existing surveillance data, it may not reliably reflect infection rates for a given catchment area, but may offer insights into COVID-19 associated deaths that were not previously identified.

Study design

Cross-Sectional

Study population and setting

The Wayne County Medical Examiner office (WCMEO) serving Wayne and Monroe countries in Michigan, piloted a surveillance strategy in which they tested 821 decedents (i.e. deceased persons) for SARS-CoV-2 infection. Decedents were flagged to be tested if they had one or more of the following: probable or confirmed COVID-19 diagnosis, symptoms (e.g. fever, shortness of breath, sneezing, coughing, chest pain, or body aches), recent travel, or contacts with probable or confirmed COVID-19 diagnosis or symptoms. WCMEO staff also tested randomly selected decedents who were not flagged. Testing took place from March 16 to July 10, 2020 through nasopharyngeal swabs. Investigators compared the socio-demographics between those who tested positive and those who did not as well as compared flagged decedents vs. non-flagged decedents.

Summary of Main Findings

Among 821 decedents tested, 230 (28%) were flagged by the COVID-19 checklist and 591 (72%) were randomly selected. The mean age among all decedents was 46. Overall, 72/821 (8.8%) tested positive for SARS-CoV-2. Those who tested positive for SARS-CoV-2 were older (mean age 53 vs. 45 among negatives, p<0.001) and Black (89% vs. 51% among negatives, p<0.001). Those who were flagged to be tested were also older on average compared to decedents who were not flagged (mean age 49 vs. 45, respectively, p<0.001). Decedents flagged by the COVID-19 checklist were more likely (20% vs. 5%, p<0.001) to test positive for SARS-CoV-2.

Study Strengths

A strength of this study is that the method of testing decedents for SARS-CoV-2 infection is a means to document cases that were asymptomatic.

Limitations

The authors try to make the case that this tool could be a potential “early warning sign” for an outbreak if it is used to supplement other forms of surveillance; however, this is unlikely to be the case as infections such as SARS-CoV-2 and influenza may already spread to epidemic levels by the time cases are documented among decedents given the known lags between rising cases and deaths. Finally, it is unclear if the cause of death for any of these decedents was due to SARS-CoV-2 infection directly as most of those who were positive had a manner of death listed as “natural, other”. The sensitivity of PCR testing to identify SARS-CoV-2 viral RNA postmortem is uncertain, so it is possible that some true deaths from COVID-19 may have been missed with postmortem testing.

Value added

This study is one of the first to test decedents as a means of SARS-CoV-2 surveillance.

This review was posted on: 2 September 2020