Fatal cases after Omicron BA.1 and BA.2 infection: Results of an autopsy study

Post-mortem transmission risk of infectious disease: A systematic review

INTRODUCTION

Autopsies may expose to infectious risks. The objective of this study is to assess the risk of post-mortem transmission of HIV, HBV, HCV, Mycobacterium tuberculosis (MBT), SARS-CoV2 and prion in the workplace and to estimate the duration of their infectiousness.

MATERIAL AND METHOD

the PRISMA 2020 guideline was used. Pubmed, Web of Science, Google Scholar and Sciencedirect databases were assessed until February 28, 2023. We searched for articles in any language and any date of publication. Studies involving animals, transmission between two living people or transmission outside the workplace were excluded. Risk of bias was assessed using the appropriate assessment tools for each type of study. A descriptive analysis was performed.

RESULTS

A total of 46 studies were included. Cases of post-mortem transmission were certain for HIV (n = 1) and MBT (n = 18). The longest post-mortem interval for positive diagnostic tests was 17 days for HIV, 60 for HBV, 7 for HCV, 36 for MBT and 17 for SARS-CoV2. The longest post-mortem interval for positive cultures was 21 h for HIV, 6 days for HBV, 36 days for MBT, 17 days for SARS-CoV2. The methodology of the studies was heterogeneous, some of them associated with a high risk of bias.

CONCLUSION

There is a lack of consistent data in the literature concerning the infectivity of cadavers, except for MBT. Legislation appears to be based on minimizing contact between the biological agent and the professional. In the absence of recent robust scientific data, workers should systematically follow the best practice recommendations.

Crucial role played by CK8+ cells in mediating alveolar injury remodeling for patients with COVID-19

The high risk of SARS-CoV-2 infection and reinfection and the occurrence of post-acute pulmonary sequelae have highlighted the importance of understanding the mechanism underlying lung repair after injury. To address this concern, comparative and systematic analyses of SARS-CoV-2 infection in COVID-19 patients and animals were conducted. In the lungs of nine patients who died of COVID-19 and one recovered from COVID-19 but died of unrelated disease in early 2020, damage-related transient progenitor (DATP) cells expressing CK8 marker proliferated significantly. These CK8+ DATP cells were derived from bronchial CK5+ basal cells. However, they showed different cell fate toward differentiation into type I alveolar cells in the deceased and convalescent patients, respectively. By using a self-limiting hamster infection model mimicking the dynamic process of lung injury remodeling in mild COVID-19 patients, the accumulation and regression of CK8+ cell marker were found to be closely associated with the disease course. Finally, we examined the autopsied lungs of two patients who died of infection by the recent Omicron variant and found that they only exhibited mild pathological injury with no CK8+ cell proliferation. These results indicate a clear pulmonary cell remodeling route and suggest that CK8+ DATP cells play a primary role in mediating alveolar remodeling, highlighting their potential applications as diagnostic markers and therapeutic targets.

What do we know about pathological mechanism and pattern of lung injury related to SARS-CoV-2 Omicron variant?

Pulmonary damage in SARS-CoV-2 is characterized pathologically by diffuse alveolar damage (DAD) and thrombosis. In addition, nosocomial bacterial superinfections and ventilator-induced lung injury (VILI) are likely to occur. The SARS-CoV-2 Omicron variant have manifested itself as a more diffusive virus which mainly affects the upper airways, such as the nose and pharynx. The mechanism leading to a lung injury with a complex clinical course for the Omicron SARS-CoV-2 variant remains unclear. A key question is whether the organ damage is due to direct organ targeting of the virus or downstream effects such as an altered immune response. An immune escape process of Omicron variant is being studied, which could lead to prolonged viral shedding and increase hospitalization times in patients with comorbidities, with an increased risk of pulmonary co-infections/superinfections and organ damage. This brief commentary reports the current knowledge on the Omicron variant and provides some useful suggestions to the scientific community.