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BackgroundThe earliest recognised infections by the SARS-CoV-2 Omicron variant (Pango lineage B.1.1.529) in Belgium and Switzerland suggested a connection to an international water polo tournament, held 12-14 November 2021 in Brno, Czechia.AimTo study the arrival and subsequent spread of the Omicron variant in Belgium and Switzerland, and understand the overall importance of this international sporting event on the number of infections in the two countries.MethodsWe performed intensive forward and backward contact tracing in both countries, supplemented by phylogenetic investigations using virus sequences of the suspected infection chain archived in public databases.ResultsThrough contact tracing, we identified two and one infected athletes of the Belgian and Swiss water polo teams, respectively, and subsequently also three athletes from Germany. In Belgium and Switzerland, four and three secondary infections, and three and one confirmed tertiary infections were identified. Phylogenetic investigation demonstrated that this sporting event played a role as the source of infection, but without a direct link with infections from South Africa and not as a superspreading event; the virus was found to already be circulating at that time in the countries involved.ConclusionThe SARS-CoV-2 Omicron variant started to circulate in Europe several weeks before its identification in South Africa on 24 November 2021. Accordingly, it can be assumed that travel restrictions are usually implemented too late to prevent the spread of newly detected SARS-CoV-2 variants to other regions. Phylogenetic analysis may modify the perception of an apparently clear result of intensive contact tracing., SCOPUS: ar.j, info:eu-repo/semantics/published

The SARS-CoV-2 Omicron variant was first identified in November 2021 in Botswana and South Africa1–3. It has since then spread to many countries and is expected to rapidly become dominant worldwide. The lineage is characterized by the presence of about 32 mutations in the spike, located mostly in the N-terminal domain (NTD) and the receptor binding domain (RBD), which may enhance viral fitness and allow antibody evasion. Here, we isolated an infectious Omicron virus in Belgium, from a traveller returning from Egypt. We examined its sensitivity to 9 monoclonal antibodies (mAbs) clinically approved or in development4, and to antibodies present in 115 sera from COVID-19 vaccine recipients or convalescent individuals. Omicron was totally or partially resistant to neutralization by all mAbs tested. Sera from Pfizer or AstraZeneca vaccine recipients, sampled 5 months after complete vaccination, barely inhibited Omicron. Sera from COVID-19 convalescent patients collected 6 or 12 months post symptoms displayed low or no neutralizing activity against Omicron. Administration of a booster Pfizer dose as well as vaccination of previously infected individuals generated an anti-Omicron neutralizing response, with titers 6 to 23 fold lower against Omicron than against Delta. Thus, Omicron escapes most therapeutic monoclonal antibodies and to a large extent vaccine-elicited antibodies. Omicron remains however neutralized by antibodies generated by a booster vaccine dose., SCOPUS: ar.j, info:eu-repo/semantics/published

Maria T Sandinha,1 Ajay K Kotagiri,1 Rona I Owen,1 Caspar Geenen,1 David HW Steel1,2 1Sunderland Eye Infirmary, Sunderland, 2Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK Purpose: To assess the accuracy of B-scan ultrasound (U/S) in diagnosing cases of acute fundus obscuring vitreous hemorrhage (FOVH) using a standardized scan protocol and dedicated ophthalmic ultrasonographer.Methods: Consecutive patients presenting with acute FOVH of unknown cause, between January 2013 and December 2014, were prospectively recruited. Patients underwent a scan performed by a dedicated ultrasonographer, utilizing a systematic scan sequence and using an ocular specific U/S device. The U/S findings were compared to the findings during vitrectomy or after spontaneous hemorrhage clearance.Results: Fifty-eight eyes (58 patients) were included. An underlying rhegmatogenous retinal detachment (RRD) and retinal tears without RRD were reported in nine and 14 patients, respectively. Nineteen of these patients underwent vitrectomy, and the other four underwent laser retinopexy or cryopexy alone. An additional six patients with suspected but uncertain retinal tears underwent vitrectomy, during which tears were confirmed in three, two had retinal vessel avulsions, and one had retinal new vessels. There was “complete” agreement between the B-scan findings and clinical findings in 78% of patients, “partial” agreement in 19%, and agreement was not tested in 3%. When the agreement was “partial”, the disagreements did not affect patient management. The sensitivity was 100% for the detection of RRD, and for the detection of new retinal tears in patients without retinal detachment.Conclusion: B-scan U/S scan was highly sensitive in identifying the pathology in acute FOVH. Our results show an improvement from previously reported results, likely related to the standardized scan protocol and dedicated ophth