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Background: The Omicron (lineage B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wales, UK on 3 December 2021. The aim of the study was to describe the first 1000 cases of the Omicron variant by demographic, vaccination status, travel and severe outcome status and compare this to contemporaneous cases of the Delta variant. Methods: Testing, typing and contact tracing data were collected by Public Health Wales and analysis undertaken by the Communicable Disease Surveillance Centre (CDSC). Risk ratios for demographic factors and symptoms were calculated comparing Omicron cases to Delta cases identified over the same time period. Results: By 14th December 2021, 1000 cases of the Omicron variant had been identified in Wales. Of the first 1000, just 3% of cases had a prior history of travel revealing rapid community transmission. A higher proportion of Omicron cases were identified in individuals aged 20-39 and most cases were double vaccinated (65.9%) or boosted (15.7%). Age adjusted analysis also revealed that Omicron cases were less likely to be hospitalised (0.4%) or report symptoms (60.8%). Specifically a significant reduction was observed in the proportion of Omicron cases reporting anosmia (8.9%). Conclusion: Key findings include a lower risk of anosmia and a reduced risk of hospitalisation in the first 1000 Omicron cases compared to co-circulating Delta cases. We also identify that existing measures for travel restrictions to control importations of new variants identified outside the UK did not prevent the rapid ingress of Omicron within Wales.

A review was undertaken of all genomic epidemiology studies on COVID-19 in long term care facilities (LTCF) that have been published to date. It was found that staff and residents were usually infected with identical, or near identical, SARS-CoV-2 genomes. Outbreaks usually involved one predominant lineage, and the same lineages persisted in LTCFs despite infection control measures. Outbreaks were most commonly due to single or few introductions followed by spread rather than a series of seeding events from the community into LTCFs. Sequencing of samples taken consecutively from the same cases showed persistence of the same genome sequence indicating that the sequencing technique was robust over time. When combined with local epidemiology, genomics facilitated likely transmission sources to be better characterised. Transmission between LTCFs was detected in multiple studies. The mortality rate amongst residents was high in all cases, regardless of the lineage. Bioinformatics methods were inadequate in one third of the studies reviewed, and reproducing the analyses was difficult as sequencing data were not available in many cases.

Regular maintenance shutdowns are required for mineral processing tanks to clean sedimentation and scale. The labour cost and loss of production during maintenance negatively impact on the economics of the operation. Swirl Flow (SF) technology was developed to improve the reliability of agitation and to maximise tank online time between maintenance intervals. This technology simplifies the engineering in agitator mechanical design with reduced shaft length and removal of baffles. Tests showed that swirling flow could provide more energy efficient suspension compared with draft tubes or multiple impeller designs. It is demonstrated that SF is capable of suspending solids at very high concentration, which is impractical with a conventional agitator. A more uniform velocity over the tank wall surface is generated under SF, free of stagnant zones in the upper corner of the tank and other areas commonly encountered in conventional agitator designs. This feature reduces the formation of large lumpy scale that could form in the stagnant zones. Compared with a conventional agitator designs, SF provides mixing homogeneity with slightly longer mixing time.