Predictors of disease severity in SARS-CoV-2 omicron variant XBB sublineages and variants of interest.

The Omicron variant has been reported to present with milder disease compared with Delta, although this may be due to immunity from vaccination and prior exposure. Predictors of severity with recent strains have not been well characterized. We retrospectively examined consecutive cases of moderate-to-severe COVID-19 (defined as requiring supplemental oxygenation, intensive care or mortality) admitted to seven tertiary hospitals across Singapore in April 2023. Whole genome sequencing was performed on each isolate to determine the sublineage, while baseline clinical, laboratory data and outcomes were tabulated. We reviewed 182 patients with moderate-to-severe illness and 466 controls hospitalized at the same time. Advanced age and presence of chronic kidney disease predicted adverse outcome. Previously reported markers such as radiographic evidence of pneumonia, elevated C-reactive protein and serum creatinine levels at presentation also correlated with adverse outcomes. There were no observable differences in outcomes with any specific Omicron XBB sublineage. We did not find any specific Omicron XBB sublineage that was associated with worse outcomes. Larger multinational studies would be important to track the clinical evolution of the virus in its current endemic state.

SARS-CoV-2 Omicron variant emerged under immune selection.

The SARS-CoV-2 Omicron variant (B.1.1.529 lineage) escapes antibodies that neutralize the ancestral virus. We tested human serum panels from participants with differing infection and vaccination status using a multiplex surrogate virus neutralization assay targeting 20 sarbecoviruses. We found that bat and pangolin sarbecoviruses showed significantly less neutralization escape than the Omicron variant. We propose that SARS-CoV-2 variants have emerged under immune selection pressure and are evolving differently from animal sarbecoviruses.

The impact of a 'milking the COW' campaign in a regional hospital in Singapore.

BACKGROUND: Computerisation of various processes in hospitals and reliance on electronic devices raises the concern of contamination of these devices from the patient environment. We undertook this study to determine if an attached hand hygiene device that unlocks the screen of a computer on wheels (COW) on usage can be effective in decreasing the microbiological burden on computer keyboards. METHODS: An electronic hand sanitizer was integrated onto the COW. A prospective cohort study with a crossover design involving 2 control and 2 intervention wards was used. The study end point was the number of colony forming units found on the keyboards. Bacteria were classified into 4 main groups; pathogenic, skin flora, from the environment or those thought to be commensals in healthy individuals. We then used a mixed effects model for the statistical analysis to determine if there were any differences before and after the intervention. RESULTS: Thirty-nine keyboards were swabbed at baseline, day 7 and 14, with 234 keyboards cultured, colony forming units (CFUs) counted and organisms isolated. By mixed model analysis, the difference of mean bacteria count between intervention and control for week 1 was 32.74 (- 32.74, CI - 94.29 to 28.75, p = 0.29), for week 2 by 155.86 (- 155.86, CI - 227.45 to - 83.53, p < 0.0001), and after the 2-week period by 157.04 (- 157.04, CI - 231.53 to - 82.67, p < 0.0001). In the sub-analysis, there were significant differences of pathogenic bacteria counts for the Intervention as compared to the Control in contrast with commensal counts. CONCLUSION: A hand hygiene device attached to a COW may be effective in decreasing the microbiological burden on computer keyboards.