Viable SARS-CoV-2 Omicron sub-variants isolated from autopsy tissues

Area of Science:

• Virology
• Pathology
• Immunology

Background:

• SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) causes COVID-19, with known pulmonary and extrapulmonary effects.
• The virus's ability to persist in various organs is established, but its viability and transmissibility from these reservoirs remain unclear.
• Persistent SARS-CoV-2 reservoirs are hypothesized to contribute to long COVID.

Purpose of the Study:

• To investigate the presence and viability of SARS-CoV-2 in autopsy tissues from individuals with documented COVID-19.
• To determine if SARS-CoV-2 can be cultured from various organs post-mortem.
• To analyze viral RNA and infectivity in lung, heart, liver, kidney, and intestinal tissues.

Main Methods:

• Analysis of autopsy tissues from 21 cadaveric donors with documented SARS-CoV-2 infection.
• Detection and quantification of viral genomic RNA using RT-qPCR.
• Assessment of virus infectivity through in vitro culture using Vero E6 cells.

Main Results:

• SARS-CoV-2 genomic RNA was detected in all analyzed tissues, with varying levels.
• Replication-competent SARS-CoV-2 was isolated from multiple tissues, indicating viable virus.
• The highest viral loads were observed in lung and heart tissues.
• Multiple Omicron sub-variants were identified, showing high sequence identity.

Conclusions:

• SARS-CoV-2 disseminates to multiple organs, including the lungs, heart, liver, kidneys, and intestines, following both primary infection and Omicron variant reinfection.
• The presence of viable virus in these tissues provides evidence for viral persistence.
• These findings enhance understanding of acute infection pathogenesis and post-acute COVID-19 sequelae.