Explore the vast range of titles available.

Highly pathogenic avian influenza A(H5N1) viruses of clade 2.3.4.4b underwent an explosive geographic expansion in 2021 among wild birds and domestic poultry across Asia, Europe, and Africa. By the end of 2021, 2.3.4.4b viruses were detected in North America, signifying further intercontinental spread. Here we show that the western movement of clade 2.3.4.4b was quickly followed by reassortment with viruses circulating in wild birds in North America, resulting in the acquisition of different combinations of ribonucleoprotein genes. These reassortant A(H5N1) viruses are genotypically and phenotypically diverse, with many causing severe disease with dramatic neurologic involvement in mammals. The proclivity of the current A(H5N1) 2.3.4.4b virus lineage to reassort and target the central nervous system warrants concerted planning to combat the spread and evolution of the virus within the continent and to mitigate the impact of a potential influenza pandemic that could originate from similar A(H5N1) reassortants. Highly pathogenic avian influenza A(H5N1) viruses of clade 2.3.4.4b underwent an explosive geographic expansion in 2021 among wild birds and domestic poultry. Here, Kandeil et al. show that the Western movement of this clade was followed by reassortment with viruses circulating in wild birds in North America which resulted in different genotypes exhibiting a wide range of disease severity in mammal models (mice, ferrets, chicken) ranging from asymptomatic disease to severe neurological pathology.

The acquisition of neuraminidase (NA) inhibitor resistance by H5N1 influenza viruses has serious clinical implications, as this class of drugs can be an essential component of pandemic control measures. The continuous evolution of the highly pathogenic H5N1 influenza viruses results in the emergence of natural NA gene variations whose impact on viral fitness and NA inhibitor susceptibility are poorly defined. We generated seven genetically stable recombinant clade 2.2 A/Turkey/15/06-like (H5N1) influenza viruses carrying NA mutations located either in the framework residues (E119A, H274Y, N294S) or in close proximity to the NA enzyme active site (V116A, I117V, K150N, Y252H). NA enzyme inhibition assays showed that NA mutations at positions 116, 117, 274, and 294 reduced susceptibility to oseltamivir carboxylate (IC(50)s increased 5- to 940-fold). Importantly, the E119A NA mutation (previously reported to confer resistance in the N2 NA subtype) was stable in the clade 2.2 H5N1 virus background and induced cross-resistance to oseltamivir carboxylate and zanamivir. We demonstrated that Y252H NA mutation contributed for decreased susceptibility of clade 2.2 H5N1 viruses to oseltamivir carboxylate as compared to clade 1 viruses. The enzyme kinetic parameters (V(max), K(m) and K(i)) of the avian-like N1 NA glycoproteins were highly consistent with their IC(50) values. None of the recombinant H5N1 viruses had attenuated virulence in ferrets inoculated with 10(6) EID(50) dose. Most infected ferrets showed mild clinical disease signs that differed in duration. However, H5N1 viruses carrying the E119A or the N294S NA mutation were lethal to 1 of 3 inoculated animals and were associated with significantly higher virus titers (P<0.01) and inflammation in the lungs compared to the wild-type virus. Our results suggest that highly pathogenic H5N1 variants carrying mutations within the NA active site that decrease susceptibility to NA inhibitors may possess increased virulence in mammalian hosts compared to drug-sensitive viruses. There is a need for novel anti-influenza drugs that target different virus/host factors and can limit the emergence of resistance.

BackgroundMultiple cases of transmission of avian H5N1 influenza viruses to humans illustrate the urgent need for an efficacious, cross-protective vaccine MethodsFerrets were immunized with inactivated whole-virus vaccine produced by reverse genetics with the hemagglutinin (HA) and neuraminidase genes of A/HK/213/03 virus. Ferrets received a single dose of vaccine (7 or 15 μg of HA) with aluminum hydroxide adjuvant or 2 doses (7 μg of HA each) without adjuvant and were challenged with 106 50% egg infectious doses of A/HK/213/03, A/HK/156/97, or A/Vietnam/1203/04 virus ResultsOne or 2 doses of vaccine induced a protective antibody response to the vaccine strain. All immunization regimens completely protected ferrets from challenge with homologous wild-type A/HK/213/03 virus: no clinical signs of infection were observed, virus replication was significantly reduced (P<.05) and was restricted to the upper respiratory tract, and spread of virus to the brain was prevented. Importantly, all vaccinated ferrets were protected against lethal challenge with the highly pathogenic strain A/Vietnam/1203/04. The 2-dose schedule induced higher levels of antibodies that were cross-reactive to antigenically distinct H5N1 viruses ConclusionsH5N1 vaccines may stimulate an immune response that is more cross-protective than what might be predicted by in vitro assays and, thus, hold potential for being stockpiled as “initial” pandemic vaccines

The acquisition of neuraminidase (NA) inhibitor resistance by H5N1 influenza viruses has serious clinical implications, as this class of drugs can be an essential component of pandemic control measures. The continuous evolution of the highly pathogenic H5N1 influenza viruses results in the emergence of natural NA gene variations whose impact on viral fitness and NA inhibitor susceptibility are poorly defined. We generated seven genetically stable recombinant clade 2.2 A/Turkey/15/06-like (H5N1) influenza viruses carrying NA mutations located either in the framework residues (E119A, H274Y, N294S) or in close proximity to the NA enzyme active site (V116A, I117V, K150N, Y252H). NA enzyme inhibition assays showed that NA mutations at positions 116, 117, 274, and 294 reduced susceptibility to oseltamivir carboxylate (IC50s increased 5- to 940-fold). Importantly, the E119A NA mutation (previously reported to confer resistance in the N2 NA subtype) was stable in the clade 2.2 H5N1 virus background and induced cross-resistance to oseltamivir carboxylate and zanamivir. We demonstrated that Y252H NA mutation contributed for decreased susceptibility of clade 2.2 H5N1 viruses to oseltamivir carboxylate as compared to clade 1 viruses. The enzyme kinetic parameters (Vmax, Km and Ki) of the avian-like N1 NA glycoproteins were highly consistent with their IC50 values. None of the recombinant H5N1 viruses had attenuated virulence in ferrets inoculated with 106 EID50 dose. Most infected ferrets showed mild clinical disease signs that differed in duration. However, H5N1 viruses carrying the E119A or the N294S NA mutation were lethal to 1 of 3 inoculated animals and were associated with significantly higher virus titers (P<0.01) and inflammation in the lungs compared to the wild-type virus. Our results suggest that highly pathogenic H5N1 variants carrying mutations within the NA active site that decrease susceptibility to NA inhibitors may possess increased virulence in mammalian hosts compared to drug-sensitive viruses. There is a need for novel anti-influenza drugs that target different virus/host factors and can limit the emergence of resistance.

Research on surgical interventions is associated with several methodological and practical challenges of which few, if any, apply only to surgery. However, surgical evaluation is especially demanding because many of these challenges coincide. In this report, the second of three on surgical innovation and evaluation, we discuss obstacles related to the study design of randomised controlled trials and non-randomised studies assessing surgical interventions. We also describe the issues related to the nature of surgical procedures—for example, their complexity, surgeon-related factors, and the range of outcomes. Although difficult, surgical evaluation is achievable and necessary. Solutions tailored to surgical research and a framework for generating evidence on which to base surgical practice are essential.

Surgery and other invasive therapies are complex interventions, the assessment of which is challenged by factors that depend on operator, team, and setting, such as learning curves, quality variations, and perception of equipoise. We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process. We also encourage the widespread use of prospective databases and registries. Reports of new techniques should be registered as a professional duty, anonymously if necessary when outcomes are adverse. Case series studies should be replaced by prospective development studies for early technical modifications and by prospective research databases for later pre-trial evaluation. Protocols for these studies should be registered publicly. Statistical process control techniques can be useful in both early and late assessment. Randomised trials should be used whenever possible to investigate efficacy, but adequate pre-trial data are essential to allow power calculations, clarify the definition and indications of the intervention, and develop quality measures. Difficulties in doing randomised clinical trials should be addressed by measures to evaluate learning curves and alleviate equipoise problems. Alternative prospective designs, such as interrupted time series studies, should be used when randomised trials are not feasible. Established procedures should be monitored with prospective databases to analyse outcome variations and to identify late and rare events. Achievement of improved design, conduct, and reporting of surgical research will need concerted action by editors, funders of health care and research, regulatory bodies, and professional societies.

Recent evidence suggests a beneficial effect of endovascular thrombectomy in acute ischaemic stroke with large infarct; however, previous trials have relied on multimodal brain imaging, whereas non-contrast CT is mostly used in clinical practice. In a prospective multicentre, open-label, randomised trial, patients with acute ischaemic stroke due to large vessel occlusion in the anterior circulation and a large established infarct indicated by an Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) of 3–5 were randomly assigned using a central, web-based system (using a 1:1 ratio) to receive either endovascular thrombectomy with medical treatment or medical treatment (ie, standard of care) alone up to 12 h from stroke onset. The study was conducted in 40 hospitals in Europe and one site in Canada. The primary outcome was functional outcome across the entire range of the modified Rankin Scale at 90 days, assessed by investigators masked to treatment assignment. The primary analysis was done in the intention-to-treat population. Safety endpoints included mortality and rates of symptomatic intracranial haemorrhage and were analysed in the safety population, which included all patients based on the treatment they received. This trial is registered with ClinicalTrials.gov, NCT03094715. From July 17, 2018, to Feb 21, 2023, 253 patients were randomly assigned, with 125 patients assigned to endovascular thrombectomy and 128 to medical treatment alone. The trial was stopped early for efficacy after the first pre-planned interim analysis. At 90 days, endovascular thrombectomy was associated with a shift in the distribution of scores on the modified Rankin Scale towards better outcome (adjusted common OR 2·58 [95% CI 1·60–4·15]; p=0·0001) and with lower mortality (hazard ratio 0·67 [95% CI 0·46–0·98]; p=0·038). Symptomatic intracranial haemorrhage occurred in seven (6%) patients with thrombectomy and in six (5%) with medical treatment alone. Endovascular thrombectomy was associated with improved functional outcome and lower mortality in patients with acute ischaemic stroke from large vessel occlusion with established large infarct in a setting using non-contrast CT as the predominant imaging modality for patient selection. EU Horizon 2020.

Long-term data showing the benefits of endovascular thrombectomy for stroke with large infarct are scarce. The TENSION trial showed the safety and efficacy of endovascular thrombectomy in patients with ischaemic stroke and large infarct at 90 days. We aimed to investigate the safety and efficacy at 12 months of endovascular thrombectomy in patients who were enrolled in the TENSION trial. TENSION was an open-label, blinded endpoint, randomised trial done at 40 hospitals across Europe and one hospital in Canada. We included patients (aged ≥18 years) with acute ischaemic stroke due to large vessel occlusion in the anterior circulation and who had a large infarct, as indicated by an Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) of 3–5 on standard-of-care stroke imaging. We randomly assigned patients (1:1) to receive either endovascular thrombectomy with medical treatment or medical treatment only up to 12 h from stroke onset. The primary outcome was functional outcome across the entire range of the modified Rankin Scale at 90 days. Here, we report the prespecified 12-month follow-up analyses for functional outcome (using the simplified modified Rankin Scale questionnaire), quality of life (using the Patient-Reported Outcomes Measurement Information System 10-item [PROMIS-10] and EQ-5D questionnaires), post-stroke anxiety and depression (using the Patient Health Questionnaire-4 [PHQ-4]), and overall survival. Outcomes (except survival) were assessed in the intention-to-treat population; the survival analysis was based on treatment received. This trial is registered with ClinicalTrials.gov, NCT03094715, and is completed. We enrolled patients between July 17, 2018, and Feb 21, 2023, when the trial was stopped early for efficacy. 253 patients were randomly assigned, 125 (49%) to endovascular thrombectomy and 128 (51%) to medical treatment only. Median follow-up was 8·36 months (IQR 0·02–12·00). Endovascular thrombectomy was associated with a shift in the distribution of scores on the modified Rankin Scale towards better functional outcome at 12 months (adjusted common odds ratio 2·39 [95% CI 1·47–3·90]). Endovascular thrombectomy was also associated with a better quality of life compared with medical treatment only, as reflected by median scores on the EQ-5D questionnaire index (0·7 [IQR 0·4–0·9] vs 0·4 [0·2–0·7]), median scores for health status on the EQ-5D questionnaire visual analogue scale (50 [IQR 35–70] vs 30 [5–60]), and median global physical health scores on the PROMIS-10 questionnaire (T-score 39·8 [IQR 37·4–50·8] vs 37·4 [32·4–44·9]); although there was not enough evidence to suggest a difference between groups in global mental health scores on PROMIS-10 (41·1 [IQR 36·3–48·3] vs 38·8 [31·3–44·7]) or the numbers of patients reporting anxiety (13 [22%] of 58 vs 15 [42%] of 36) and depression (18 [31%] vs 18 [50%]) on PHQ-4. Overall survival was slightly better in the endovascular thrombectomy group compared with medical treatment only (adjusted hazard ratio 0·70 [95% CI 0·50–0·99]). In patients with acute ischaemic stroke from large vessel occlusion with established large infarct, compared with medical treatment only, endovascular thrombectomy was associated at 12 months after stroke with better functional outcome, quality of life, and overall survival. These findings suggest that the benefits of endovascular thrombectomy in patients with an ischaemic stroke and a large infarct are sustained in the long term and support the use of endovascular thrombectomy in these patients. European Union Horizon 2020 Research and Innovation Programme.