Whole-Genome Sequencing of SARS-CoV-2 Infection in a Cluster of Immunocompromised Children in Indonesia

The role of real-time, on-site, whole-genome sequencing of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in guiding the management of hospital outbreaks of coronavirus disease 2019 (COVID-19)

OBJECTIVE

We aimed to demonstrate the role of real-time, on-site, whole-genome sequencing (WGS) of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in the management of hospital outbreaks of coronavirus disease 2019 (COVID-19).

DESIGN

This retrospective study was undertaken at our institutions in Sydney, New South Wales, Australia, between July 2021 and April 2022. We included SARS-CoV-2 outbreaks due to SARS-CoV-2 δ (delta) and ο (omicron) variants. All unexpected SARS-CoV-2-positive cases identified within the hospital were managed by the infection control team. An outbreak was defined as 2 or more cases acquired on a single ward. We included only outbreaks with 2 or more suspected transmission events in which WGS was utilized to assist with outbreak assessment and management.

RESULTS

We studied 8 outbreaks involving 266 patients and 486 staff, of whom 73 (27.4%) and 39 (8.0%), respectively, tested positive for SARS-CoV-2 during the outbreak management. WGS was used to evaluate the source of the outbreak, to establish transmission chains, to highlight deficiencies in infection control practices, and to delineate between community and healthcare acquired infection.

CONCLUSIONS

Real-time, on-site WGS combined with epidemiologic assessment is a useful tool to guide management of hospital SARS-CoV-2 outbreaks. WGS allowed us (1) to establish likely transmission events due to personal protective equipment (PPE) breaches; (2) to detect inadequacies in infection control infrastructure including ventilation; and (3) to confirm multiple viral introductions during periods of high community SARS-CoV-2 transmission. Insights gained from WGS-guides outbreak management directly influenced policy including modifying PPE requirements, instituting routine inpatient SARS-CoV-2 surveillance, and confirmatory SARS-CoV-2 testing prior to placing patients in a cohort setting.

Promising use of immune cell-derived exosomes in the treatment of SARS-CoV-2 infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is persistently threatening the lives of thousands of individuals globally. It triggers pulmonary oedema, driving to dyspnoea and lung failure. Viral infectivity of coronavirus disease 2019 (COVID-19) is a genuine challenge due to the mutagenic genome and mysterious immune-pathophysiology. Early reports highlighted that extracellular vesicles (exosomes, Exos) work to enhance COVID-19 progression by mediating viral transmission, replication and mutations. Furthermore, recent studies revealed that Exos derived from immune cells play an essential role in the promotion of immune cell exhaustion by transferring regulatory lncRNAs and miRNAs from exhausted cells to the active cells. Fortunately, there are great chances to modulate the immune functions of Exos towards a sustained repression of COVID-19. Engineered Exos hold promising immunotherapeutic opportunities for remodelling cytotoxic T cells' function. Immune cell-derived Exos may trigger a stable epigenetic repression of viral infectivity, restore functional cytokine-producing T cells and rebalance immune response in severe infections by inducing functional T regulatory cells (Tregs). This review introduces a view on the current outcomes of immunopathology, and immunotherapeutic applications of immune cell-derived Exos in COVID-19, besides new perspectives to develop novel patterns of engineered Exos triggering novel anti-SARS-CoV-2 immune responses.