High viral loads: what drives fatal cases of COVID-19 in vaccinees? an autopsy study (preprint)

Background: The rate of SARS-CoV-2 breakthrough infections in vaccinees is becoming an increasingly serious issue. Objective: To determine the causes of death, histological organ alteration, and viral spread in relation to demographic, clinical-pathological, viral variants, and vaccine types. Design: Comprehensive retrospective observational cohort study. Setting: Consecutive cases from four German academic medical centers. Patients: Deceased with proven SARS-CoV-2 infection after vaccination who died between January and November 2021. Collections of 29 vaccinees which were analyzed and compared to 141 nonvaccinated control cases. Results: Autopsies were performed on 16 partially and 13 fully vaccinated individuals. Most patients were elderly and suffered from several relevant comorbidities. Real-time RT-PCR (RT-qPCR) identified a significantly increased rate of generalized viral dissemination within the organism in vaccinated cases versus nonvaccinated cases (45% vs. 16%, respectively; P = 0.008). Vaccinated cases also showed high viral loads, reaching Ct values below 10, especially in the upper airways and lungs. This was accompanied by high rates of pulmonal bacterial or mycotic superinfections and the occurrence of immunocompromising factors such as malignancies, immunosuppressive drug intake, or decreased immunoglobulin levels. All these findings were particularly accentuated in partially vaccinated patients compared to fully vaccinated individuals. A fatal course after vaccination occurred in only 14% of all COVID-19 deceased in Augsburg. Limitations: Restricted number of cases Conclusions: Fatal cases of COVID-19 in vaccinees were rare and often associated with severe comorbidities or other immunosuppressive conditions. Interestingly, we observed striking virus dissemination in our case study, which may indicate a decreased ability to eliminate the virus in patients with an impaired immune system. However, the potential role of antibody-dependent enhancement must also be ruled out in future studies.

Contamination of personal protective equipment during COVID-19 autopsies (preprint)

Confronted with an emerging infectious disease, the medical community faced relevant concerns regarding the performance of autopsies of COVID-19 deceased at the beginning of the pandemic. This attitude has changed, and autopsies are now recognized as indispensable tools for elucidating COVID-19; despite this, the true risk of infection for autopsy staff is still debated. To elucidate the rate of SARS-CoV-2 contamination in personal protective equipment (PPE), swabs were taken at nine locations of the PPE of one physician and an assistant each from 11 full autopsies performed at four different centers. Further samples were obtained for three minimally invasive autopsies (MIA) conducted at a fifth center. Lung/bronchus swabs of the deceased served as positive controls. SARS-CoV-2 RNA was detected by RT-qPCR. In 9/11 full autopsies PPE samples were tested RNA positive with PCR, in total 21% of all PPE samples taken. The main contaminated parts of the PPE were the gloves (64% positive), the aprons (50% positive), and the upper sides of shoes (36% positive) while for example the fronts of safety goggles were only positive in 4.5% of the samples and all face masks were negative. In MIA, viral RNA was observed in one sample from a glove, but not in other swabs. Infectious virus isolation in cell culture was performed in RNA positive swabs from full autopsies. Of all RNA positive PPE samples, 21% of the glove samples were positive for infectious virus taken in 3/11 full autopsies. In conclusion, in >80% of autopsies, PPE was contaminated with viral RNA. In >25% of autopsies, PPE was found to be even contaminated with infectious virus, signifying a potential risk of infection among autopsy staff. Adequate PPE and hygiene measures, including appropriate waste deposition, are therefore mandatory to enable safe work environment.

Beta-cells from patients with COVID-19 and from isolated human islets exhibit ACE2, DPP4, and TMPRSS2 expression, viral infiltration and necroptotic cell death (preprint)

Here we report a possible mechanistic link between coronavirus disease 2019 (COVID-19) and diabetes. In addition to its known role on the respiratory system, the human coronavirus SARS-CoV-2 has been shown to affect the endocrine system including the pancreas 1-4. It has been suggested that the virus can induce type 1 diabetes 5-8. Therefore, we isolated human pancreatic islets and examined the expression of angiotensin-converting enzyme 2 (ACE2) and the protease TMPRSS2, known to be important for SARS-CoV-2 entry 9. Furthermore, we investigated the expression of an alternative entry receptor, dipeptidyl peptidase-4 (DPP4 also known as CD26) 10. We found all three proteins expressed in pancreatic beta-cells and confirmed that beta-cells are permissive to infection with SARS-CoV-2 pseudoviruses. Additionally, we performed a comprehensive analysis of ACE2, TMPRSS2 and DPP4 expression in pancreata of 10 patients who died of COVID-19. We report significant variation between the samples and detected the highest levels of ACE2 and DPP4 expression in patients exhibiting SARS-CoV-2 infiltration shown by confocal microscopy, RNAscope and electron microscopy. Furthermore, necroptotic cell death was observed in beta-cells of the COVID-19 patients. Taken together, these data suggest that SARS-CoV-2 viral infection of pancreatic beta-cells may trigger necroptosis and islet impairment.