Background Emergence of variants with specific mutations in key epitopes in the spike protein of SARS-CoV-2 raises concerns pertinent to mass vaccination campaigns and use of monoclonal antibodies. We aimed to describe the emergence of the B.1.1.7 variant of concern (VOC), including virological characteristics and clinical severity in contemporaneous patients with and without the variant. Methods In this cohort study, samples positive for SARS-CoV-2 on PCR that were collected from Nov 9, 2020, for patients acutely admitted to one of two hospitals on or before Dec 20, 2020, in London, UK, were sequenced and analysed for the presence of VOC-defining mutations. We fitted Poisson regression models to investigate the association between B.1.1.7 infection and severe disease (defined as point 6 or higher on the WHO ordinal scale within 14 days of symptoms or positive test) and death within 28 days of a positive test and did supplementary genomic analyses in a cohort of chronically shedding patients and in a cohort of remdesivir-treated patients. Viral load was compared by proxy, using PCR cycle threshold values and sequencing read depths. Findings Of 496 patients with samples positive for SARS-CoV-2 on PCR and who met inclusion criteria, 341 had samples that could be sequenced. 198 (58%) of 341 had B.1.1.7 infection and 143 (42%) had non-B.1.1.7 infection. We found no evidence of an association between severe disease and death and lineage (B.1.1.7 vs non-B.1.1.7) in unadjusted analyses (prevalence ratio [PR] 0·97 [95% CI 0·72–1·31]), or in analyses adjusted for hospital, sex, age, comorbidities, and ethnicity (adjusted PR 1·02 [0·76–1·38]). We detected no B.1.1.7 VOC-defining mutations in 123 chronically shedding immunocompromised patients or in 32 remdesivir-treated patients. Viral load by proxy was higher in B.1.1.7 samples than in non-B.1.1.7 samples, as measured by cycle threshold value (mean 28·8 [SD 4·7] vs 32·0 [4·8]; p=0·0085) and genomic read depth (1280 [1004] vs 831 [682]; p=0·0011). Interpretation Emerging evidence exists of increased transmissibility of B.1.1.7, and we found increased virus load by proxy for B.1.1.7 in our data. We did not identify an association of the variant with severe disease in this hospitalised cohort. Funding University College London Hospitals NHS Trust, University College London/University College London Hospitals NIHR Biomedical Research Centre, Engineering and Physical Sciences Research Council.

Videolaryngoscopy (VL) may improve the success of orotracheal intubation compared with direct laryngoscopy (DL). We performed a systematic search of PubMed, Embase, and CENTRAL databases for studies comparing VL and DL for emergency orotracheal intubations outside the operating room. The primary outcome was rate of first-pass intubation, with subgroup analyses by location, device used, clinician experience, and clinical scenario. The secondary outcome was complication rates. Data are presented as [odds ratio (95% confidence intervals); P-values]. We identified 32 studies with 15 064 emergency intubations. There was no difference in first-pass intubation with VL compared with DL [OR=1.28, (0.99-1.65); P=0.06]. First-pass intubations were increased with VL compared with DL in the intensive care unit (ICU) [2.02 (1.43-2.85); P<0.001], and similar in the emergency department or pre-hospital setting. First-pass intubations were similar with GlideScope, but improved with the CMAC [1.32 (1.08-1.62); P=0.007] compared with DL. There was greater first-pass intubation with VL compared with DL amongst novice/trainee clinicians [OR=1.95 (1.45-2.64); P<0.001], but not amongst experienced clinicians or paramedics/nurses. There was no difference in first-pass intubation with VL compared with DL during cardiopulmonary resuscitation or trauma. VL compared with DL was associated with fewer oesophageal intubations [OR=0.32 (0.14-0.70); P=0.003], but more arterial hypotension [OR=1.49 (1.00-2.23); P=0.05]. In summary, VL compared with DL is associated with greater first-pass emergency intubation in the ICU and amongst less experienced clinicians, and reduces oesophageal intubations. However, VL is associated with greater incidence of arterial hypotension. Further trials investigating the utility of VL over DL in specific situations are required.

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