Detection and infectivity of SARS-CoV-2 in exhumated corpses.

Postmortem detection of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) after the exhumation of a corpse can become important, e.g. in the case of subsequent medical malpractice allegations. To date, data on possible detection periods [e.g. by reverse transcription polymerase chain reaction (RT-PCR)] or on the potential infectivity of the virus after an exhumation are rare. In the present study, these parameters were examined in two cases with a time span of approximately 4 months between day of death and exhumation. Using SARS-CoV-2 RT-PCR on swabs of both lungs and the oropharynx detection was possible with cycle threshold (Ct) values of about 30 despite signs of beginning decay. RT-PCR testing of perioral and perinasal swabs and swabs collected from the inside of the body bag, taken to estimate the risk of infection of those involved in the exhumation, was negative. Cell culture-based infectivity testing was negative for both, lung and oropharyngeal swabs. In one case, RT-PCR testing at the day of death of an oropharyngeal swab showed almost identical Ct values as postmortem testing of an oropharyngeal swab, impressively demonstrating the stability of viral RNA in the intact corpse. However, favorable climatic conditions in the grave have to be taken into account, as it was wintertime with constant low temperatures. Nevertheless, it was possible to demonstrate successful postmortem detection of SARS-CoV-2 infection following exhumation even after months in an earth grave.

Re-positive of SARS-CoV-2 test is common in COVID-19 patients after hospital discharge. Data from high standard post-discharge quarantined patients in Macao SAR, China.

During the pandemic of COVID-19, Macau faces tremendous pressure because it is a famous gambling and tourism city with the world's highest population density. The Macau government implemented decisive public health intervention to control the transmission of COVID-19, and there were only two independent outbreaks in Macau. In the second outbreak, all 35 cases were infected in foreign countries. They were quarantined in airborne infection isolation rooms for at least 14 days with reverse transcription-polymerase chain reaction (RT-PCR) tests after hospital discharge. Twelve (34.3%) of them had re-positive SARS-CoV-2 test results, and none of them presented any COVID-19 signs or symptoms during the entire quarantine period. In this study, the re-positive patients were more likely to be diagnosed in the early stage of the disease with a longer hospital stay. Virus re-infection is impossible in this high standard isolation setting, and reactivation is also unlikely, so that residual virus nucleic acid should be the possible reason for this phenomenon. Due to limited data about the risk of re-positive patients, it is better to quarantine patients after discharge for a prolonged period with repeat RT-PCR tests to minimize the community's potential risk, particularly in the regions with relative plenty of resources and low community infection rate such as Macau.

The Issue of Recurrently Positive Patients Who Recovered From COVID-19 According to the Current Discharge Criteria: Investigation of Patients from Multiple Medical Institutions in Wuhan, China.

The current discharge criteria for COVID-19 require that patients have 2 consecutive negative results for reverse transcription polymerase chain reaction (RT-PCR) detection. Here, we observed that recurrent positive RT-PCR test results in patients with 3 consecutive negative results (5.4%) were significantly decreased compared with those in patients with 2 consecutive negative results (20.6%); such patients reported positive RT-PCR test results within 1 to 12 days after meeting the discharge criteria. These results confirmed that many recovered patients could show a positive RT-PCR test result, and most of these patients could be identified by an additional RT-PCR test prior to discharge.