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Background: Nirsevimab, a long-acting monoclonal antibody, has been approved for the prevention of respiratory syncytial virus (RSV) infection in infants. In France, more than 210 000 single doses were administered in infants younger than 1 year during the 2023-24 season. In this context, the selection and spread of escape variants might be a concern. Here, we aimed to characterise RSV associated with breakthrough infection., Methods: We did a multicentre, national, observational study in France during the 2023-24 RSV season in RSV-infected infants (aged <1 year) who either received or did not receive a dose of nirsevimab before their first RSV season. We excluded infants with insufficient information about nirsevimab treatment or without parental consent. We used respiratory samples collected in each laboratory for full-length RSV RNA sequencing to analyse changes in the nirsevimab binding site Ø. We tested clinical RSV isolates for neutralisation by nirsevimab. We analysed F candidate substitutions by fusion-inhibition assay., Findings: Of the 695 RSV infected infants, we analysed 545 (78%) full-length RSV genome sequences: 260 (48%) from nirsevimab-treated breakthrough infections (236 [91%] RSV-A and 24 [9%] RSV-B) and 285 (52%) from untreated RSV-infected infants (236 [83%] RSV-A and 49 [17%] RSV-B). Analysis of RSV-A did not reveal any substitution in site Ø known to be associated with resistance to nirsevimab. Two (8%) of 24 RSV-B breakthrough infections had resistance-associated substitutions: F:N208D (dominant resistance-associated substitution) and a newly described F:I64M plus F:K65R combination (minority resistance-associated substitution), both of which induced high levels of resistance in the fusion-inhibition assay., Interpretation: This study is, to the best of our knowledge, the largest genotypic and phenotypic surveillance study of nirsevimab breakthrough infections to date. Nirsevimab breakthrough variants remain very rare despite the drug's widespread use. The detection of resistance-associated substitutions in the RSV-B F protein highlights the importance of active molecular surveillance., Funding: ANRS Maladies Infectieuses Emergentes and the French Ministry of Health and Prevention., Competing Interests: Declaration of interests SF has served as a speaker for GlaxoSmithKline, AstraZeneca, MSD, Pfizer, Cepheid, and Moderna. IE received support by R-Biopharm for attending meetings. CR has served as a speaker for Pfizer and received support by Tecan for attending meetings. J-MP has served as an advisor or speaker for Abbott, Abbvie, Gilead, and GlaxoSmithKline. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Respiratory syncytial virus (RSV) is a major cause of hospitalisations and deaths among infants worldwide. France was one of the first countries to implement a national programme (beginning on Sept 15, 2023) for administration of nirsevimab, a single-dose long-acting monoclonal antibody treatment, to infants born on or after Feb 6, 2023, to prevent lower respiratory tract infection caused by RSV. We aimed to estimate the effectiveness of nirsevimab and the number of hospitalisations averted in children younger than 24 months in real-world settings., Methods: In this modelling study, we developed an age-structured deterministic model characterising RSV transmission as well as plausible scenarios for the administration of nirsevimab doses based on maternity ward and community pharmacy supply data. We retrospectively estimated nirsevimab effectiveness in infants younger than 24 months during the 2023-24 RSV season in France (excluding overseas territories) and the number of averted hospitalisations for RSV bronchiolitis occurring after emergency department visits, by calibrating the model to hospital and virological surveillance data from Aug 21, 2017, to Feb 4, 2024, alongside serological data from a previous cross-sectional study. To assess the robustness of our estimates, we conducted sensitivity analyses in which we modified our assumptions about the number of doses administered, the reconstruction of the number of RSV-associated hospitalisations for bronchiolitis, the duration of maternal and post-infection immunity to RSV, and the number of contacts in children aged 0-2 months., Findings: We estimated that nirsevimab administration prevented 5800 (95% credible interval 3700-7800) RSV-associated hospitalisations for bronchiolitis after emergency department visits among children younger than 24 months, including 4200 (2900-5600) hospitalisations among those aged 0-2 months, between Sept 15, 2023 (the date nirsevimab was introduced), and Feb 4, 2024-a 23% (16-30) reduction in the total number of hospitalisations and a 35% (25-44) reduction in the 0-2 months age group, compared with the scenario without administration. In our baseline scenario, in which we estimated that 215 000 doses of nirsevimab were administered by Jan 31, 2024, the estimated effectiveness against RSV-associated hospitalisations for bronchiolitis was 73% (61-84), corresponding to one hospitalisation averted for every 39 (26-54) doses administered. In sensitivity analyses, nirsevimab remained effective against RSV-associated hospitalisations for bronchiolitis after emergency department attendance., Interpretation: Our findings show that nirsevimab administration campaigns could effectively reduce the RSV-related hospital burden of bronchiolitis in children younger than 24 months., Funding: European Commission, Laboratoire d'Excellence Integrative Biology of Emerging Infectious Diseases programme, and INCEPTION project., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Respiratory syncytial virus (RSV) poses a substantial threat to infants, often leading to challenges in hospital capacity. With recent pharmaceutical developments to be used during the prenatal and perinatal periods aimed at decreasing the RSV burden, there is a pressing need to identify infants at risk of severe disease. We aimed to stratify the risk of developing a clinically severe RSV infection in infants under 1 year of age., Methods: This retrospective observational study was conducted at the Hospices Civils de Lyon, France, involving infants born between 2014 and 2018. This study focused on infants hospitalized with severe and very severe acute lower respiratory tract infections associated with RSV (SARI-WI group). Data collection included perinatal information and clinical data, with machine-learning algorithms used to discriminate SARI-WI cases from nonhospitalized infants., Results: Of 42,069 infants, 555 developed SARI-WI. Infants born in November were very likely (>80%) predicted SARI-WI. Infants born in October were very likely predicted SARI-WI except for births at term by vaginal delivery and without siblings. Infants were very unlikely (<10%) predicted SARI-WI when all the following conditions were met: born in other months, at term, by vaginal delivery and without siblings. Other infants were possibly (10-30%) or probably (30-80%) predicted SARI-WI., Conclusions: Although RSV preventive measures are vital for all infants, and specific recommendations exist for patients with high-risk comorbidities, in situations where prioritization becomes necessary, infants born just before or within the early weeks of the epidemic should be considered as a risk group., Competing Interests: M.C.N. reports grants from the Bill & Melinda Gates Foundation, European & Developing Countries Clinical Trials Partnership, Pfizer, AstraZeneca, and Sanofi; and personal fees Sanofi. The other authors have no funding or conflicts of interest to disclose., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Nonpharmaceutical interventions (NPIs) implemented during the COVID-19 pandemic have disrupted the dynamics of respiratory syncytial virus (RSV) on a global scale; however, the cycling of RSV subtypes in the pre- and post-pandemic period remains poorly understood. Here, we used a two subtype RSV model supplemented with epidemiological data to study the impact of NPIs on the two circulating subtypes, RSV-A and RSV-B. The model is calibrated to historic RSV subtype data from the United Kingdom and Finland and predicts a tendency for RSV-A dominance over RSV-B immediately following the implementation of NPIs. Using a global genetic dataset, we confirm that RSV-A has prevailed over RSV-B in the post-pandemic period, consistent with a higher R 0 for RSV-A. With new RSV infant monoclonals and maternal and elderly vaccines becoming widely available, these results may have important implications for understanding intervention effectiveness in the context of disrupted subtype dynamics., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Objectives: We aimed to study whether the percentwise age distribution of RSV cases changes over time during annual epidemics., Methods: We used surveillance data (2008-2019) from the Netherlands, Lyon (France), Portugal, Singapore, Ecuador, South Africa, and New Zealand. In each country, every season was divided into "epidemic quarters", i.e. periods corresponding to each quartile of RSV cases. Multinomial logistic regression models were fitted to evaluate whether the likelihood of RSV cases being aged <1 or ≥5 years (vs. 1 to <5) changed over time within a season., Results: In all countries, RSV cases were significantly more likely to be aged <1 year in the 4th vs. 1st epidemic quarter; the relative risk ratio [RRR] ranged between 1.35 and 2.56. Likewise, RSV cases were significantly more likely to be aged ≥5 years in the 4th vs. 1st epidemic quarter (except in Singapore); the RRR ranged from 1.75 to 6.70. The results did not change when stratifying by level of care or moving the lower cut-off to 6 months., Conclusions: The age profile of RSV cases shifts within a season, with infants and adolescents, adults, and the elderly constituting a higher proportion of cases in the later phases of annual epidemics. These findings may have implications for RSV prevention policies with newly approved vaccines., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: M.B. and R.K. are Sanofi employees and may hold shares and/or stock options in the company. J.P. reports that Nivel has received RSV research grants from the Foundation for Influenza Epidemiology and Sanofi. The remaining authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This retrospective study aimed to compare the mortality and burden of respiratory syncytial virus (RSV group), SARS-CoV-2 (COVID-19 group), non-H1N1 (Seasonal influenza group) and H1N1 influenza (H1N1 group) in adult patients admitted to intensive care unit (ICU) with respiratory failure. A total of 807 patients were included. Mortality was compared between the four following groups: RSV, COVID-19, seasonal influenza, and H1N1 groups. Patients in the RSV group had significantly more comorbidities than the other patients. At admission, patients in the COVID-19 group were significantly less severe than the others according to the simplified acute physiology score-2 (SAPS-II) and sepsis-related organ failure assessment (SOFA) scores. Using competing risk regression, COVID-19 (sHR = 1.61; 95% CI 1.10; 2.36) and H1N1 (sHR = 1.87; 95% CI 1.20; 2.93) were associated with a statistically significant higher mortality while seasonal influenza was not (sHR = 0.93; 95% CI 0.65; 1.31), when compared to RSV. Despite occurring in more severe patients, RSV and seasonal influenza group appear to be associated with a more favorable outcome than COVID-19 and H1N1 groups., (© 2024. The Author(s).)

The H274Y substitution (N2 numbering) in neuraminidase (NA) N1 confers oseltamivir resistance to A(H1N1) influenza viruses. This resistance has been associated with reduced N1 expression using transfected cells, but the effect of this substitution on the enzymatic properties and on the expression of other group-1-NA subtypes is unknown. The aim of the present study was to evaluate the antiviral resistance, enzymatic properties, and expression of wild-type (WT) and H274Y-substituted NA for each group-1-NA. To this end, viruses with WT or H274Y-substituted NA (N1pdm09 or avian N4, N5 or N8) were generated by reverse genetics, and for each reverse-genetic virus, antiviral susceptibility, NA affinity (Km), and maximum velocity (Vm) were measured. The enzymatic properties were coupled with NA quantification on concentrated reverse genetic viruses using mass spectrometry. The H274Y-NA substitution resulted in highly reduced inhibition by oseltamivir and normal inhibition by zanamivir and laninamivir. This resistance was associated with a reduced affinity for MUNANA substrate and a conserved Vm in all viruses. NA quantification was not significantly different between viruses carrying WT or H274Y-N1, N4 or N8, but was lower for viruses carrying H274Y-N5 compared to those carrying a WT-N5. In conclusion, the H274Y-NA substitution of different group-1-NAs systematically reduced their affinity for MUNANA substrate without a significant impact on NA Vm. The impact of the H274Y-NA substitution on viral NA expression was different according to the studied NA.

BackgroundThere is currently no standardised approach to estimate respiratory syncytial virus (RSV) epidemics' timing (or seasonality), a critical information for their effective prevention and control.AimWe aimed to provide an overview of methods to define RSV seasonality and identify factors supporting method choice or interpretation/comparison of seasonal estimates.MethodsWe systematically searched PubMed and Embase (2016-2021) for studies using quantitative approaches to determine the start and end of RSV epidemics. Studies' features (data-collection purpose, location, regional/(sub)national scope), methods, and assessment characteristics (case definitions, sampled population's age, in/outpatient status, setting, diagnostics) were extracted. Methods were categorised by their need of a denominator (i.e. numbers of specimens tested) and their retrospective vs real-time application. Factors worth considering when choosing methods and assessing seasonal estimates were sought by analysing studies.ResultsWe included 32 articles presenting 49 seasonality estimates (18 thereof through the 10% positivity threshold method). Methods were classified into eight categories, two requiring a denominator (1 retrospective; 1 real-time) and six not (3 retrospective; 3 real-time). A wide range of assessment characteristics was observed. Several studies showed that seasonality estimates varied when methods differed, or data with dissimilar assessment characteristics were employed. Five factors (comprising study purpose, application time, assessment characteristics, healthcare system and policies, and context) were identified that could support method choice and result interpretation.ConclusionMethods and assessment characteristics used to define RSV seasonality are heterogeneous. Our categorisation of methods and proposed framework of factors may assist in choosing RSV seasonality methods and interpretating results.

We initiated a nationwide prospective study to monitor respiratory syncytial virus (RSV)-related pediatric hospitalizations in 46 hospitals throughout the Netherlands between May 2021 and August 2022. We showed year-round RSV transmission in the Netherlands after an initial 2021 summer outbreak. The pattern was unprecedented and distinct from neighboring countries. We extended a dynamic simulation model to evaluate the impact of waning immunity on pediatric RSV hospitalizations in the Netherlands using 4 different scenarios. Our results suggest that the observed continuous RSV transmission pattern could be associated with waning immunity due to the period of very low RSV circulation during the COVID-19 pandemic., Competing Interests: Potential conflicts of interest. L. B. has regular interaction with pharmaceutical and other industrial partners but has not received personal fees or other personal benefits. University Medical Center Utrecht (UMCU) has received major funding (>€100 000 per industrial partner) for investigator-initiated studies from AbbVie, MedImmune, Janssen, the Bill & Melinda Gates Foundation, Nutricia (Danone), and MeMed Diagnostics; major cash or in-kind funding as part of the public–private partnership Innovative Medicines Initiative–funded RESCEU project from GSK, Novavax, Janssen, AstraZeneca, Pfizer, and Sanofi; major funding by Julius Clinical for participating in the INFORM study sponsored by MedImmune; minor funding for participation in trials by Regeneron and Janssen during 2015–2017 (total annual estimate less than €20 000); and minor funding for consultation and invited lectures by AbbVie, MedImmune, Ablynx, Bavaria Nordic, MabXience, Novavax, Pfizer, and Janssen (total annual estimate less than €20 000). L. B. is the founding chairman of the ReSViNET Foundation. V. E. P. has received reimbursement from Merck and Pfizer for travel expenses to scientific input engagements on respiratory syncytial virus. D. M. W. has received consulting fees from Pfizer, Merck, GSK, Affinivax, and Matrivax for work unrelated to this manuscript and is the principal investigator on research grants from Pfizer and Merck on work unrelated to this manuscript. Z. Z. is expected to receive consulting fees from Pfizer for work unrelated to this manuscript. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Preventive measures applied during the COVID-19 pandemic have modified the age distribution, the clinical severity and the incidence of Respiratory Syncytial Virus (RSV) hospitalisations during the 2020/21 RSV season. The aim of the present study was to estimate the impact of these aspects on RSV-associated hospitalisations (RSVH) costs stratified by age group between pre-COVID-19 seasons and 2020/21 RSV season., Methods: We compared the incidence, the median costs, and total RSVH costs from the national health insurance perspective in children < 24 months of age during the COVID-19 period (2020/21 RSV season) with a pre-COVID-19 period (2014/17 RSV seasons). Children were born and hospitalised in the Lyon metropolitan area. RSVH costs were extracted from the French medical information system (Programme de Médicalisation des Systémes d'Information)., Results: The RSVH-incidence rate per 1000 infants aged < 3 months decreased significantly from 4.6 (95 % CI [4.1; 5.2]) to 3.1 (95 % CI [2.4; 4.0]), and increased in older infants and children up to 24 months of age during the 2020/21 RSV season. Overall, RSVH costs for RSVH cases aged below 2 years old decreased by €201,770 (31 %) during 2020/21 RSV season compared to the mean pre-COVID-19 costs., Conclusions: The sharp reduction in costs of RSVH in infants aged < 3 months outweighed the modest increase in costs observed in the 3-24 months age group. Therefore, conferring a temporal protection through passive immunisation to infants aged < 3 months should have a major impact on RSVH costs even if it results in an increase of RSVH in older children infected later in life. Nevertheless, stakeholders should be aware of this potential increase of RSVH in older age groups presenting with a wider range of disease to avoid any bias in estimating the cost-effectiveness of passive immunisation strategies., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: J.S.C participated as an expert to Pfizer scientific advisory board and in PROMISE General Assembly. J.S.C. did not receive funding for these activities., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: National Influenza Centers (NICs) have played a crucial role in the surveillance of SARS-CoV-2. The FluCov project, covering 22 countries, was initiated to monitor the impact of the SARS-CoV-2 pandemic on influenza activity., Methods: This project consisted of an epidemiological bulletin and NIC survey. The survey, designed to assess the impact of the pandemic on the influenza surveillance system, was shared with 36 NICs located across 22 countries. NICs were invited to reply between November 2021 and March 2022., Results: We received 18 responses from NICs in 14 countries. Most NICs (76%) indicated that the number of samples tested for influenza decreased. Yet, many NICs (60%) were able to increase their laboratory testing capacity and the "robustness" (e.g., number of sentinel sites) (59%) of their surveillance systems. In addition, sample sources (e.g., hospital or outpatient setting) shifted. All NICs reported a higher burden of work following the onset of the pandemic, with some NICs hiring additional staff or partial outsourcing to other institutes or departments. Many NICs anticipate the future integration of SARS-CoV-2 surveillance into the existing respiratory surveillance system., Discussion: The survey shows the profound impact of SARS-CoV-2 on national influenza surveillance in the first 27 months of the pandemic. Surveillance activities were temporarily disrupted, whilst priority was given to SARS-CoV-2. However, most NICs have shown rapid adaptive capacity underlining the importance of strong national influenza surveillance systems. These developments have the potential to benefit global respiratory surveillance in the years to come; however, questions about sustainability remain., Competing Interests: JP, MDR, SC, and LS declare that Nivel has previously received RSV research grants from Sanofi Pasteur/AstraZeneca, the Foundation for Influenza Epidemiology, and the European Union's Innovative Medicines Initiative. CEG, ED, and MA are Sanofi employees and may hold shares and/or stock options in the company. The other authors have no conflicts of interest to declare., (© 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Background: The emergence of COVID-19 triggered the massive implementation of non-pharmaceutical interventions (NPI) which impacted the circulation of respiratory syncytial virus (RSV) during the 2020/2021 season., Methods: A time-series susceptible-infected-recovered (TSIR) model was used early September 2021 to forecast the implications of this disruption on the future 2021/2022 RSV epidemic in Lyon urban population., Results: When compared to observed hospital-confirmed cases, the model successfully captured the early start, peak timing, and end of the 2021/2022 RSV epidemic. These simulations, added to other streams of surveillance data, shared and discussed among the local field experts were of great value to mitigate the consequences of this atypical RSV outbreak on our hospital paediatric department., Conclusions: TSIR model, fitted to local hospital data covering large urban areas, can produce plausible post-COVID-19 RSV simulations. Collaborations between modellers and hospital management (who are both model users and data providers) should be encouraged in order to validate the use of dynamical models to timely allocate hospital resources to the future RSV epidemics., Competing Interests: Disclosure of interest: The authors completed the ICMJE Disclosure of Interest Form (available upon request from the corresponding author) and disclose no relevant interests., (Copyright © 2023 by the Journal of Global Health. All rights reserved.)

Background: The nucleoprotein (N protein) of respiratory syncytial virus (RSV) is a candidate antigen for new RSV vaccine development. The aim of the present study was to investigate the association between maternal antibody titers against the RSV N protein at birth and the newborns' risk of developing very severe lower respiratory tract infection (VS-LRTI)., Methods: In this single-center prospective cohort study, 578 infants born during the RSV epidemic season in France were included. Among these, 36 were hospitalized for RSV VS-LRTI. A generalized linear model was used to test the occurrence of a VS-LRTI in function of sex, mode of delivery, parity of the mother, type of pregnancy, date of birth in relation to the peak of the epidemic, and antibody titer against N protein., Results: All cord blood samples had detectable antibodies against N protein. The mean titers were significantly lower in newborns with risk factors for RSV severe LRTI (preterm infants, birth before the peak epidemic, multiparous mother). There was no association between antibody titer against the N protein and a protection against VS-LRTI., Conclusions: Further studies are needed to support the hypothesis that transfer of maternal antibodies against the RSV N protein can provide a significant immune protection early in infancy and that N protein candidate vaccine may be a suitable target for maternal vaccine., (© 2022 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-α2 alone (five patients) or with IFN-ω (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia. Nine and four patients had antibodies neutralizing high and low concentrations, respectively, of IFN-α2, and six and two patients had antibodies neutralizing high and low concentrations, respectively, of IFN-ω. The patients' autoantibodies increased influenza A virus replication in both A549 cells and reconstituted human airway epithelia. The prevalence of these antibodies was significantly higher than that in the general population for patients <70 yr of age (5.7 vs. 1.1%, P = 2.2 × 10-5), but not >70 yr of age (3.1 vs. 4.4%, P = 0.68). The risk of critical influenza was highest in patients with antibodies neutralizing high concentrations of both IFN-α2 and IFN-ω (OR = 11.7, P = 1.3 × 10-5), especially those <70 yr old (OR = 139.9, P = 3.1 × 10-10). We also identified 10 patients in additional influenza patient cohorts. Autoantibodies neutralizing type I IFNs account for ∼5% of cases of life-threatening influenza pneumonia in patients <70 yr old., (© 2022 Zhang et al.)

Similarly to many respiratory viruses, respiratory syncytial virus (RSV) is surprising in its ability to reinfect children and adults who have already been immunized. It is not so much in the evolution of its genome that we must look for the cause, but more probably in the structure/function of its viral proteins, which are capable of interfering with the immune response and memory. After an incubation of three to eight days, RSV infection most often results in nasopharyngitis with little or no fever. RSV infection of the respiratory epithelium is characterized by marked mucus production, desquamation of infected respiratory cells and persistent impairment of mucociliary transport. The extension of the infection to the lower respiratory tract therefore contributes to the formation of mucous plugs obstructing the lumen of the bronchioles. This is the cause of the clinical most commonly associated with RSV infection: bronchiolitis in newborns and infants which is a frequent reason for hospitalization due to secondary respiratory and digestive complications. The recent data from the literature, however, indicate that by far the most frequent complication is a community infection: acute otitis media. RSV infections are therefore a very common reason for the prescription of antibiotics., Competing Interests: J.-S. Casalegno déclare faire partie du comité scientifique d’une étude non rémunérée menée par Pfizer sur le VRS.

Introduction: Preterm infants are at risk of lower respiratory tract infections (LRTI), including Respiratory Syncytial Virus (RSV) associated bronchiolitis, for which palivizumab prophylaxis can be proposed. Our aim was to determine risk factors of very severe RSV disease in children born before 34 weeks of gestation., Methods: Among 2,101 infants born before 34 weeks of gestation in 3 maternity wards between 2012 and 2017, the laboratory confirmed RSV-infected patients requiring hospitalization before 12 months of corrected age were retrospectively included. We collected data about the neonatal period, the palivizumab prophylaxis and the hospitalization for a RSV-related LRTI. LRTI was considered as very severe (VS-LRTI) when patients required invasive or non-invasive positive pressure ventilation., Results: Among 86 included patients, 31 met the criteria of VS-LRTI. The VS-LRTI patients had a higher birth gestational age and weight but less heart disease and bronchopulmonary dysplasia. They received palivizumab prophylaxis less frequently than the other patients but the difference was not significant. At the onset of infection, VS-LRTI patients had a younger corrected age for prematurity and presented more frequently with apnea, bradycardia, life-threatening event, hemodynamic failure, hypercapnia. Using logistic regression, the main factor associated with VS-LRTI was a younger corrected age for prematurity at the onset of infection [Odd ratio for each month of corrected age = 0.77 (0.62; 0.93), p = 0.012]., Conclusion: Infants at the highest risk of VS-LRTI were infants with a younger corrected age for prematurity. Therefore, a better targeting of infants requiring palivizumab prophylaxis and early interventions at hospital discharge could limit VS-LRTI in these infants., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mulot, Benchaib, Plaisant, Ploin, Gillet, Javouhey, Claris, Picaud, Casalegno and Butin.)

Background: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infection in young children. We previously estimated that in 2015, 33·1 million episodes of RSV-associated acute lower respiratory infection occurred in children aged 0-60 months, resulting in a total of 118 200 deaths worldwide. Since then, several community surveillance studies have been done to obtain a more precise estimation of RSV associated community deaths. We aimed to update RSV-associated acute lower respiratory infection morbidity and mortality at global, regional, and national levels in children aged 0-60 months for 2019, with focus on overall mortality and narrower infant age groups that are targeted by RSV prophylactics in development., Methods: In this systematic analysis, we expanded our global RSV disease burden dataset by obtaining new data from an updated search for papers published between Jan 1, 2017, and Dec 31, 2020, from MEDLINE, Embase, Global Health, CINAHL, Web of Science, LILACS, OpenGrey, CNKI, Wanfang, and ChongqingVIP. We also included unpublished data from RSV GEN collaborators. Eligible studies reported data for children aged 0-60 months with RSV as primary infection with acute lower respiratory infection in community settings, or acute lower respiratory infection necessitating hospital admission; reported data for at least 12 consecutive months, except for in-hospital case fatality ratio (CFR) or for where RSV seasonality is well-defined; and reported incidence rate, hospital admission rate, RSV positive proportion in acute lower respiratory infection hospital admission, or in-hospital CFR. Studies were excluded if case definition was not clearly defined or not consistently applied, RSV infection was not laboratory confirmed or based on serology alone, or if the report included fewer than 50 cases of acute lower respiratory infection. We applied a generalised linear mixed-effects model (GLMM) to estimate RSV-associated acute lower respiratory infection incidence, hospital admission, and in-hospital mortality both globally and regionally (by country development status and by World Bank Income Classification) in 2019. We estimated country-level RSV-associated acute lower respiratory infection incidence through a risk-factor based model. We developed new models (through GLMM) that incorporated the latest RSV community mortality data for estimating overall RSV mortality. This review was registered in PROSPERO (CRD42021252400)., Findings: In addition to 317 studies included in our previous review, we identified and included 113 new eligible studies and unpublished data from 51 studies, for a total of 481 studies. We estimated that globally in 2019, there were 33·0 million RSV-associated acute lower respiratory infection episodes (uncertainty range [UR] 25·4-44·6 million), 3·6 million RSV-associated acute lower respiratory infection hospital admissions (2·9-4·6 million), 26 300 RSV-associated acute lower respiratory infection in-hospital deaths (15 100-49 100), and 101 400 RSV-attributable overall deaths (84 500-125 200) in children aged 0-60 months. In infants aged 0-6 months, we estimated that there were 6·6 million RSV-associated acute lower respiratory infection episodes (4·6-9·7 million), 1·4 million RSV-associated acute lower respiratory infection hospital admissions (1·0-2·0 million), 13 300 RSV-associated acute lower respiratory infection in-hospital deaths (6800-28 100), and 45 700 RSV-attributable overall deaths (38 400-55 900). 2·0% of deaths in children aged 0-60 months (UR 1·6-2·4) and 3·6% of deaths in children aged 28 days to 6 months (3·0-4·4) were attributable to RSV. More than 95% of RSV-associated acute lower respiratory infection episodes and more than 97% of RSV-attributable deaths across all age bands were in low-income and middle-income countries (LMICs)., Interpretation: RSV contributes substantially to morbidity and mortality burden globally in children aged 0-60 months, especially during the first 6 months of life and in LMICs. We highlight the striking overall mortality burden of RSV disease worldwide, with one in every 50 deaths in children aged 0-60 months and one in every 28 deaths in children aged 28 days to 6 months attributable to RSV. For every RSV-associated acute lower respiratory infection in-hospital death, we estimate approximately three more deaths attributable to RSV in the community. RSV passive immunisation programmes targeting protection during the first 6 months of life could have a substantial effect on reducing RSV disease burden, although more data are needed to understand the implications of the potential age-shifts in peak RSV burden to older age when these are implemented., Funding: EU Innovative Medicines Initiative Respiratory Syncytial Virus Consortium in Europe (RESCEU)., (Copyright © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infection- related hospitalisations in infants (RSVh). Most of these infants are younger than 6 months old with no known risk factors. An efficient RSVh prevention program should address both mothers and infants, relying on Non-Pharmaceutical (NPI) and Pharmaceutical Interventions (PI). This study aimed at identifying the target population for these two interventions., Methods: Laboratory-confirmed RSV-infected infants hospitalised during the first 6 months of life were enrolled from the Hospices Civils de Lyon birth cohort (2014 to 2018). Clinical variables related to pregnancy and birth (sex, month of birth, birth weight, gestational age, parity) were used for descriptive epidemiology, multivariate logistic regression, and predictive score development., Results: Overall, 616 cases of RSVh in 45,648 infants were identified. Being born before the epidemic season, prematurity, and multiparity were independent predictors of RSVh. Infants born in January or June to August with prematurity and multiparity, and those born in September or December with only one other risk factor (prematurity or multiparity) were identified as moderate-risk, identifying the mothers as candidates for a first-level NPI prevention program. Infants born in September or December with prematurity and multiparity, and those born in October or November were identified as high-risk, identifying the mothers and infants as candidates for a second-level (NPI and PI) intervention., Conclusions: It is possible to determine predictors of RSVh at birth, allowing early enrollment of the target population in a two-level RSV prevention intervention.

Background: SARS-Cov-2 (COVID-19) has become a major worldwide health concern since its appearance in China at the end of 2019., Objective: To evaluate the intrinsic mortality and burden of COVID-19 and seasonal influenza pneumonia in ICUs in the city of Lyon, France., Design: A retrospective study., Setting: Six ICUs in a single institution in Lyon, France., Patients: Consecutive patients admitted to an ICU with SARS-CoV-2 pneumonia from 27 February to 4 April 2020 (COVID-19 group) and seasonal influenza pneumonia from 1 November 2015 to 30 April 2019 (influenza group). A total of 350 patients were included in the COVID-19 group (18 refused to consent) and 325 in the influenza group (one refused to consent). Diagnosis was confirmed by RT-PCR. Follow-up was completed on 1 April 2021., Main Outcomes and Measures: Differences in 90-day adjusted-mortality between the COVID-19 and influenza groups were evaluated using a multivariable Cox proportional hazards model., Results: COVID-19 patients were younger, mostly men and had a higher median BMI, and comorbidities, including immunosuppressive condition or respiratory history were less frequent. In univariate analysis, no significant differences were observed between the two groups regarding in-ICU mortality, 30, 60 and 90-day mortality. After Cox modelling adjusted on age, sex, BMI, cancer, sepsis-related organ failure assessment (SOFA) score, simplified acute physiology score SAPS II score, chronic obstructive pulmonary disease and myocardial infarction, the probability of death associated with COVID-19 was significantly higher in comparison to seasonal influenza [hazard ratio 1.57, 95% CI (1.14 to 2.17); P = 0.006]. The clinical course and morbidity profile of both groups was markedly different; COVID-19 patients had less severe illness at admission (SAPS II score, 37 [28 to 48] vs. 48 [39 to 61], P < 0.001 and SOFA score, 4 [2 to 8] vs. 8 [5 to 11], P < 0.001), but the disease was more severe considering ICU length of stay, duration of mechanical ventilation, PEEP level and prone positioning requirement., Conclusion: After ICU admission, COVID-19 was associated with an increased risk of death compared with seasonal influenza. Patient characteristics, clinical course and morbidity profile of these diseases is markedly different., (Copyright © 2022 European Society of Anaesthesiology and Intensive Care. Unauthorized reproduction of this article is prohibited.)

Background: In critically ill COVID-19 patients, the initial response to SARS-CoV-2 infection is characterized by major immune dysfunctions. The capacity of these severe patients to mount a robust and persistent SARS-CoV-2 specific T cell response despite the presence of severe immune alterations during the ICU stay is unknown., Methods: Critically ill COVID-19 patients were sampled five times during the ICU stay and 9 and 13 months afterwards. Immune monitoring included counts of lymphocyte subpopulations, HLA-DR expression on monocytes, plasma IL-6 and IL-10 concentrations, anti-SARS-CoV-2 IgG levels and T cell proliferation in response to three SARS-CoV-2 antigens., Findings: Despite the presence of major lymphopenia and decreased monocyte HLA-DR expression during the ICU stay, convalescent critically ill COVID-19 patients consistently generated adaptive and humoral immune responses against SARS-CoV-2 maintained for more than one year after hospital discharge. Patients with long hospital stays presented with stronger anti-SARS-CoV-2 specific T cell response but no difference in anti-SARS-CoV2 IgG levels., Interpretation: Convalescent critically ill COVID-19 patients consistently generated a memory immune response against SARS-CoV-2 maintained for more than one year after hospital discharge. In recovered individuals, the intensity of SARS-CoV-2 specific T cell response was dependent on length of hospital stay., Funding: This observational study was supported by funds from the Hospices Civils de Lyon, Fondation HCL, Claude Bernard Lyon 1 University and Région Auvergne Rhône-Alpes and by partial funding by REACTing (Research and ACTion targeting emerging infectious diseases) INSERM, France and a donation from Fondation AnBer (http://fondationanber.fr/)., Competing Interests: Declaration of interests MB, CT, KBG, VC and MAC are bioMérieux's employees. This private company had no role in the study design, result analysis and decision to publish this study. PV received consulting fees and payment for a literature review from Pfizer and Astellas. All other authors have declared no conflicts of interest., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

There is growing experimental evidence that many respiratory viruses-including influenza and SARS-CoV-2-can interact, such that their epidemiological dynamics may not be independent. To assess these interactions, standard statistical tests of independence suggest that the prevalence ratio-defined as the ratio of co-infection prevalence to the product of single-infection prevalences-should equal unity for non-interacting pathogens. As a result, earlier epidemiological studies aimed to estimate the prevalence ratio from co-detection prevalence data, under the assumption that deviations from unity implied interaction. To examine the validity of this assumption, we designed a simulation study that built on a broadly applicable epidemiological model of co-circulation of two emerging or seasonal respiratory viruses. By focusing on the pair influenza-SARS-CoV-2, we first demonstrate that the prevalence ratio systematically underestimates the strength of interaction, and can even misclassify antagonistic or synergistic interactions that persist after clearance of infection. In a global sensitivity analysis, we further identify properties of viral infection-such as a high reproduction number or a short infectious period-that blur the interaction inferred from the prevalence ratio. Altogether, our results suggest that ecological or epidemiological studies based on co-detection prevalence data provide a poor guide to assess interactions among respiratory viruses.

As in past pandemics, co-circulating pathogens may play a role in the epidemiology of coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In particular, experimental evidence indicates that influenza infection can up-regulate the expression of ACE2-the receptor of SARS-CoV-2 in human cells-and facilitate SARS-CoV-2 infection. Here we hypothesized that influenza impacted the epidemiology of SARS-CoV-2 during the early 2020 epidemic of COVID-19 in Europe. To test this hypothesis, we developed a population-based model of SARS-CoV-2 transmission and of COVID-19 mortality, which simultaneously incorporated the impact of non-pharmaceutical control measures and of influenza on the epidemiological dynamics of SARS-CoV-2. Using statistical inference methods based on iterated filtering, we confronted this model with mortality incidence data in four European countries (Belgium, Italy, Norway, and Spain) to systematically test a range of assumptions about the impact of influenza. We found consistent evidence for a 1.8-3.4-fold (uncertainty range across countries: 1.1 to 5.0) average population-level increase in SARS-CoV-2 transmission associated with influenza during the period of co-circulation. These estimates remained robust to a variety of alternative assumptions regarding the epidemiological traits of SARS-CoV-2 and the modeled impact of control measures. Although further confirmatory evidence is required, our results suggest that influenza could facilitate the spread and hamper effective control of SARS-CoV-2. More generally, they highlight the possible role of co-circulating pathogens in the epidemiology of COVID-19., Competing Interests: Matthieu Domenech de Cellès received postdoctoral funding (2017–2019) from Pfizer and consulting fees from GSK. Jean-Sebastien Casalegno declares no competing interests. Bruno Lina is chair of the ISC for the Global Influenza Surveillance Network, and co-chair of the Global Influenza and RSV initiative; he is also a member of the French COVID- 19 Scientific Committee (no personal income for all these activities). Lulla Opatowski has received consulting fees from WHO for work on antimicrobial resistance and funding from Pfizer (2017–2019)., (©2021 Domenech de Cellès et al.)

The Rhône-Loire metropolitan areas' 2020/21 respiratory syncytial virus (RSV) epidemic was delayed following the implementation of non-pharmaceutical interventions (NPI), compared with previous seasons. Very severe lower respiratory tract infection incidence among infants ≤ 3 months decreased twofold, the proportion of cases among children aged > 3 months to 5 years increased, and cases among adults > 65 years were markedly reduced. NPI appeared to reduce the RSV burden among at-risk groups, and should be promoted to minimise impact of future RSV outbreaks.

Since the introduction of non-pharmacological interventions to control COVID-19, respiratory syncytial virus (RSV) activity in Europe has been limited. Surveillance data for 17 countries showed delayed RSV epidemics in France (≥ 12 w) and Iceland (≥ 4 w) during the 2020/21 season. RSV cases (predominantly small children) in France and Iceland were older compared with previous seasons. We hypothesise that future RSV epidemic(s) could start outside the usual autumn/winter season and be larger than expected. Year-round surveillance of RSV is of critical importance.

Objectives: To analyse functional outcome parameters according to antimicrobial treatments after respiratory syncytial virus (RSV)-confirmed infection in adult lung transplant recipients., Methods: A 9-year retrospective multicentre cohort study (2011-19) included adult lung transplant recipients with RSV-confirmed infection. The first endpoint determined new allograft dysfunction (acute graft rejection and chronic lung allograft dysfunction (CLAD)) 3 months after infection. Then baseline and 3 months' postinfection forced expiratory volume in 1 second (FEV 1 ) values were compared according to antimicrobial treatment. Univariate logistic regression analysis was performed., Results: RSV infection was confirmed in 77 of 424 lung transplant recipients (estimated incidence of 0.025 per patient per year; 95% confidence interval 0.018-0.036). At 3 months, 22 recipients (28.8%) developed allograft dysfunction: ten (13%) possible CLAD, six (7.9%) acute rejection and six (7.9%) CLAD. Recipients with the lowest preinfection FEV 1 had a greater risk of developing pneumonia (median (interquartile range) 1.5 (1.1-1.9) vs. 2.2 (1.5-2.4) L/s, p 0.003) and a higher odds of receiving antibiotics (1.6 (1.3-2.3) vs. 2.3 (1.9-2.5) L/s, p 0.017; odds ratio 0.52, 95% confidence interval 0.27-0.99). Compared to tracheobronchitis/bronchiolitis, RSV-induced pneumonia led more frequently to hospitalization (91.7%, 22 vs. 58.0%, 29, p 0.003) and intensive care unit admission (33.3%, 8 vs. 0, p < 10 -3 ). For ribavirin-treated recipients (24.7%, 19) and azithromycin prophylaxis (50.6%, 39), 3-month FEV 1 values were not different from untreated recipients. The overall mortality was 2.5% at 1 month and 5.3% at 6 months, unrelated to RSV., Conclusions: At 3 months after RSV-confirmed infection, 22 recipients (28.8%) had new allograft dysfunction. Ribavirin treatment and azithromycin prophylaxis did not prevent FEV 1 decline., (Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Despite the particular focus given to influenza since the 2009 influenza A(H1N1) pandemic, true burden of influenza-associated critical illness remains poorly known. The aim of this study was to identify factors influencing influenza burden imposed on intensive care units (ICUs) in a catchment population during recent influenza seasons. From 2008 to 2013, all adult patients admitted with a laboratory-confirmed influenza infection to one of the ICUs in the catchment area were prospectively included. A total of 201 patients (mean age: 63 ± 16, sex-ratio: 1.1) were included. The influenza-related ICU-bed occupancy rate averaged 4.3% over the five influenza seasons, with the highest mean occupancy rate (16.9%) observed during the 2012 winter. In-hospital mortality for the whole cohort was 26%. Influenza A(H1N1)pdm infections (pdm in the mentioned nomenclature refers to Pandemic Disease Mexico 2009), encountered in 51% of cases, were significantly associated with neither longer length of stay nor higher mortality (ICU and hospital) when compared to infections with other virus subtypes. SOFA score (OR, 1.12; 95% CI, 1.04-1.29) was the only independent factor significantly associated with a prolonged hospitalization. These results highlight both the frequency and the severity of influenza-associated critical illness, leading to a sustained activity in ICUs. Severity of the disease, but not A(H1N1)pdm virus, appears to be a major determinant of ICU burden related to influenza.

Background: Since the onset of the pandemic, only few studies focused on longitudinal immune monitoring in critically ill COVID-19 patients with acute respiratory distress syndrome (ARDS) whereas their hospital stay may last for several weeks. Consequently, the question of whether immune parameters may drive or associate with delayed unfavorable outcome in these critically ill patients remains unsolved., Methods: We present a dynamic description of immuno-inflammatory derangements in 64 critically ill COVID-19 patients including plasma IFNα2 levels and IFN-stimulated genes (ISG) score measurements., Results: ARDS patients presented with persistently decreased lymphocyte count and mHLA-DR expression and increased cytokine levels. Type-I IFN response was initially induced with elevation of IFNα2 levels and ISG score followed by a rapid decrease over time. Survivors and non-survivors presented with apparent common immune responses over the first 3 weeks after ICU admission mixing gradual return to normal values of cellular markers and progressive decrease of cytokines levels including IFNα2. Only plasma TNF-α presented with a slow increase over time and higher values in non-survivors compared with survivors. This paralleled with an extremely high occurrence of secondary infections in COVID-19 patients with ARDS., Conclusions: Occurrence of ARDS in response to SARS-CoV2 infection appears to be strongly associated with the intensity of immune alterations upon ICU admission of COVID-19 patients. In these critically ill patients, immune profile presents with similarities with the delayed step of immunosuppression described in bacterial sepsis.

Objectives: We aimed to describe bacterial co-infections and acute respiratory distress (ARDS) outcomes according to influenza type and subtype., Methods: A retrospective observational study was conducted from 2012 to 2016 in patients admitted to the respiratory intensive care unit (ICU) of Marseille university hospital for influenza-induced ARDS. Microbiological investigations, including multiplex molecular respiratory panel testing and conventional bacteriological cultures, were performed as part of the routine ICU care on the bronchoalveloar lavage collected at admission. Bacterial co-infections, ICU mortality and respiratory function were investigated according to virus type and subtype., Results: Among the 45 ARDS patients included, A(H1N1)pdm09 was the most frequent influenza virus identified (28/45 A(H1N1)pdm09, eight out of 45 A(H3N2) and nine out of 45 influenza B). Bacterial co-infections involving a total of 23 bacteria were diagnosed in 16/45 patients (36%). A(H1N1)pdm09 patients presented fewer bacterial co-infections (17.9% vs. 50.0% for A(H3N2) patients and 77.8% for B patients; p < 0.01). Overall, mortality at 90 days post admission was 33.3% (15/45), and there was no significant difference between influenza type and subtype. The need for extracorporeal membrane oxygenation was more frequent for A(H1N1)pdm2009 (20/28, 71.4%) and B patients (7/9, 77.8%) than the A(H3N2) subtype (1/8, 12.5%; p < 0.01). A(H1N1)pdm09-ARDS patients were associated with fewer ventilation-free days at day 28 (median (IQR): 0 (0-8) days) compared with other influenza-ARDS patients (15 (0-25) days, p < 0.05)., Discussion: In a population of influenza-induced ARDS, A(H1N1)pdm09 was associated with fewer bacterial co-infections but poorer respiratory outcomes. These data underline the major role of A(H1N1)pdm09 subtype on influenza disease severity., (Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Diagnosis and epidemiological analysis of human parvovirus B19 (hB19V) infections are essential for disease management in severely ill patients. This study aimed to evaluate the performance of an optimized NS1-VP1u nested PCR for detection and sequencing of viruses in clinical samples using 224 clinical and five reference samples. PCR sensitivity, specificity, and positive and negative predictive values were perfect (100%). While phylogenetic analysis of a 615 bp-long fragment demonstrated that the viruses in all of the samples belonged to genotype 1, this study confirmed that this optimized PCR could detect all known hB19V with high performance.

Respiratory syncytial virus (RSV) has been recognized as responsible for severe respiratory illness in adults, especially in the elderly. While pneumonia is commonly observed during RSV infection, the burden and epidemiology of bacterial superinfection is poorly understood. The aim of this study was to identify microorganisms associated with RSV-positive pneumonia in adults. A retrospective study was conducted during three consecutive winters (October to April 2013-2016) in the University Hospital of Lyon, France. During RSV circulation periods, a systematic RSV screening was performed by reverse-transcription PCR on all respiratory samples collected from adults. Records of RSV-positive patients were subsequently analyzed to identify radiologically confirmed pneumonia cases. Bacteria were identified by standard bacteriology cultures or urinary antigen screening and classified as potentially causative of pneumonia if quantification was above the specific threshold as defined by the European Manual of Clinical Microbiology. Overall, 14,792 adult respiratory samples were screened for RSV detection by PCR. In total, 292 had a positive RSV detection (2.0%) among which 89 presented with pneumonia including 27 bacterial superinfections (9.3%) with Streptococcus pneumonia, Haemophilus influenza, Staphylococcus aureus, Pseudomonas aeruginosa, and Moraxella catarrhalis. Most patients were elderly (55.6%) and patients with comorbidities (77.8%). A more severe outcome was observed for RSV-bacteria-associated pneumonia compared with RSV pneumonia: length of stay was significantly longer (16 days vs 10 days) and ICU hospitalization more frequent (66.7% vs 21.0%) (p < 0.05). In conclusion, we did not observe major differences in the epidemiology of bacterial superinfections in RSV-positive pneumonia compared to reports on post-influenza pneumonia.

Objectives: We aimed to describe direct medical costs of annual RSV-associated hospitalisation in the first year of life., Methods: Retrospective cohort study in Lyon, France (2012-2016). A case was defined as a laboratory confirmed RSV-infection with hospitalisation in the first year of life. Hospital costs were estimated based on the French version of Diagnosis Related Groups., Results: Overall, 350 cases in 21,930 children were identified. Incidence of RSV-associated hospitalisation in the first year of life per 1000 births was 14.5 (95% CI 13.4-15.6). Related direct medical annual costs were 364,269 €, mostly attributed to children born during the RSV season (231,959 €) and children born premature (108,673 €)., Conclusion: Medical costs for RSV-associated hospitalisation of newborns are higher for children born premature or born during the RSV season. Prioritised targeting of those groups may facilitate a cost-efficient strategy for the national prevention program., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: In recent years, metagenomic Next-Generation Sequencing (mNGS) has increasingly been used for an accurate assumption-free virological diagnosis. However, the systematic workflow evaluation on clinical respiratory samples and implementation of quality controls (QCs) is still lacking., Methods: A total of 3 QCs were implemented and processed through the whole mNGS workflow: a no-template-control to evaluate contamination issues during the process; an internal and an external QC to check the integrity of the reagents, equipment, the presence of inhibitors, and to allow the validation of results for each sample. The workflow was then evaluated on 37 clinical respiratory samples from patients with acute respiratory infections previously tested for a broad panel of viruses using semi-quantitative real-time PCR assays (28 positive samples including 6 multiple viral infections; 9 negative samples). Selected specimens included nasopharyngeal swabs (n = 20), aspirates (n = 10), or sputums (n = 7)., Results: The optimal spiking level of the internal QC was first determined in order to be sufficiently detected without overconsumption of sequencing reads. According to QC validation criteria, mNGS results were validated for 34/37 selected samples. For valid samples, viral genotypes were accurately determined for 36/36 viruses detected with PCR (viral genome coverage ranged from 0.6 to 100%, median = 67.7%). This mNGS workflow allowed the detection of DNA and RNA viruses up to a semi-quantitative PCR Ct value of 36. The six multiple viral infections involving 2 to 4 viruses were also fully characterized. A strong correlation between results of mNGS and real-time PCR was obtained for each type of viral genome (R 2 ranged from 0.72 for linear single-stranded (ss) RNA viruses to 0.98 for linear ssDNA viruses)., Conclusions: Although the potential of mNGS technology is very promising, further evaluation studies are urgently needed for its routine clinical use within a reasonable timeframe. The approach described herein is crucial to bring standardization and to ensure the quality of the generated sequences in clinical setting. We provide an easy-to-use single protocol successfully evaluated for the characterization of a broad and representative panel of DNA and RNA respiratory viruses in various types of clinical samples.

In 2009, the co-circulation of H5N1 and H1N1pdm09 raised concerns that a reassortment event may lead to highly pathogenic influenza strains. H1N1pdm09 and H5N1 are able to infect the same target cells of the lower respiratory tract. To investigate the capacity of the emergence of reassortant viruses, we characterized viruses obtained from the co-infection of cells with H5N1 (A/Turkey/13/2006) and H1N1pdm09 (A/Lyon/969/2009 H1N1). In our analysis, all the screened reassortants possessed the PB2, HA, and NP segments from H5N1 and acquired one or two of the H1N1pdm09 segments. Moreover, the in vivo infections showed that the acquisition of the NS segment from H1N1pdm09 increased the virulence of H5N1 in mice. We conclude, therefore, that reassortment can occur between these two viruses, even if this process has never been detected in nature.

In patients with influenza, morbidity and mortality are strongly influenced by infections with Staphylococcus aureus producing high amounts of certain toxins. Here we tested the impact of influenza virus on the pro-inflammatory and cytotoxic actions of a panel of S. aureus virulence factors, including Panton-Valentine Leucocidin (PVL), phenol-soluble modulin α1 (PSMα1) and 3 (PSMα3), α-hemolysin (Hla), and cell wall components, i.e., heat-killed S. aureus (HKSA) and protein A. We initially screened for potential synergic interactions using a standardized in vitro model in influenza-infected continuous human monocytic cell lines. Then we tested the identified associations using an ex vivo model in influenza-infected human monocytes freshly isolated from blood. Co-exposure to influenza virus and HKSA, PVL, PSMα1, and PSMα3 increased NF-κB/AP-1 pathway activation in THP1-XBlue cells, and co-exposure to influenza virus and PVL increased cytotoxicity in U937 cells. In monocytes isolated from blood, the synergy between influenza virus and HKSA was confirmed based on cytokine production (TNF-α, IL-1β, IL-6), and co-exposure to influenza virus and Hla-increased cytotoxicity. Our findings suggest that influenza virus potentiates the pro-inflammatory action of HKSA and contributes to the cytotoxicity of Hla on monocytes. Synergic interactions identified in the cell-line model must be cautiously interpreted since few were relevant in the ex vivo model.

Background: Respiratory syncytial virus (RSV) is a well-recognized cause of respiratory tract infections. Based on G gene variations, 11 RSV-A and 36 RSV-B genotypes have been described to date. The ON1 genotype was detected in Ontario in 2010 and subsequently reported in several countries., Objectives: The objective of the present study was to investigate for the first time the RSV epidemiology and genotype diversity in France between 2010 and 2014., Study Design: All respiratory samples received from patients with influenza-like illness or respiratory tract infection were screened for RSV infection by RT-PCR. The results were stratified according to winter season. Among the RSV-positive cases, 117 samples were further investigated for phylogenetic analysis out of 150 randomly selected for sequencing., Results: Among the 20,359 cases screened, 14% of the cases were RSV-positive. RSV-A was predominant during the four winter seasons. The first ON1 variant was detected during the 2010-2011 winter and reached 85% of all RSV-A-positive cases in 2013-2014. Most RSV-B was classified as BA9 and BA10 genotypes but a new genotype (BA-Ly) was described., Conclusion: As reported in different countries, ON1 variants were firstly detected in 2011 and became the predominant RSV-A genotype in Lyon. Among RSV-B, BA9 was predominant but detected alongside BA10 or a transient genotype (BA-Ly)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

International case definitions recommended by the Centers for Disease Control and Prevention (CDC), the European Centre for Disease Prevention and Control (ECDC), and the World Health Organization (WHO) are commonly used for influenza surveillance. We evaluated clinical factors associated with the laboratory-confirmed diagnosis of influenza and the performance of these influenza case definitions by using a complete dataset of 14,994 patients with acute respiratory infection (ARI) from whom a specimen was collected between August 2009 and April 2014 by the Groupes Régionaux d'Observation de la Grippe (GROG), a French national influenza surveillance network. Cough and fever ≥ 39 °C most accurately predicted an influenza infection in all age groups. Several other symptoms were associated with an increased risk of influenza (headache, weakness, myalgia, coryza) or decreased risk (adenopathy, pharyngitis, shortness of breath, otitis/otalgia, bronchitis/ bronchiolitis), but not throughout all age groups. The WHO case definition for influenza-like illness (ILI) had the highest specificity with 21.4%, while the ECDC ILI case definition had the highest sensitivity with 96.1%. The diagnosis among children younger than 5 years remains challenging. The study compared the performance of clinical influenza definitions based on outpatient surveillance and will contribute to improving the comparability of data shared at international level., (This article is copyright of The Authors, 2017.)

Context: Seasonal flu outbreaks are linked to the circulation of influenza virus type A or B. Special attention has always been paid to influenza A epidemics; but recently, several studies have investigated the impact of influenza B virus epidemics, particularly as, since the 1980s, two antigenically different influenza B lineages co-circulate, raising the issue of vaccine matching., Objectives: We present the results of influenza B burden during nine influenza seasons (2003-2013) and vaccine matching of the circulating lineages., Patients and Methods: Clinical and virological influenza surveillance data, collected by the Regional Groups for Influenza Surveillance Network in France, allows for studying the burden of influenza in the practice of the population of ambulatory care physicians., Results and Conclusion: Our analysis is based on 37,801 samples, of which 12,036 were virologically confirmed influenza cases (31.8%), including 3576 cases of influenza B (29.7% of influenza cases). Influenza B viruses significantly circulated during six seasons. For each season, the influenza B epidemic peaked later than the influenza A epidemic. Influenza B is very common in children of school age but also affects other age groups. Finally, more than one-third of the analyzed influenza B viruses belonged to a different lineage than the one used in the composition of the trivalent vaccine. Our results are comparable to those described in other countries., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Objectives: While subtype-specific substitutions linked to neuraminidase (NA) inhibitor resistance are well described in human N1 and N2 influenza NAs, little is known about other NA subtypes. The aim of this study was to determine whether the R292K and E119V ± I222L substitutions could be associated with oseltamivir resistance in all group 2 NAs and had an impact on virus fitness., Methods: Reassortant viruses with WT NA or variant N2, N3, N6, N7 or N9 NAs, bearing R292K or E119V ± I222L substitutions, were produced by reverse genetics. The antiviral susceptibility, activity, K m of the NA, mutation stability and in vitro virus fitness in MDCK cells were determined., Results: NA activities could be ranked as follows regardless of the substitution: N3 ≥ N6 > N2 ≥ N9 > N7. Using NA inhibitor resistance interpretation criteria used for human N1 or N2, the NA-R292K substitution conferred highly reduced inhibition by oseltamivir and the N6- or N9-R292K substitution conferred reduced inhibition by zanamivir and laninamivir. Viruses with the N3- or N6-E119V substitution showed normal inhibition by oseltamivir, while those with the N2-, N7- or N9-E119V substitution showed reduced inhibition by oseltamivir. Viruses with NA-E119V + I222L substitutions showed reduced inhibition (N3 and N6) or highly reduced inhibition (N2, N7 and N9) by oseltamivir. Viruses bearing the NA-R292K substitution had lower affinity and viruses bearing the NA-E119V substitution had higher affinity for the MUNANA substrate than viruses with corresponding WT NA., Conclusions: NA-R292K and E119V + I222L substitutions conferred reduced inhibition by oseltamivir for all group 2 NAs. Surveillance of NA inhibitor resistance for zoonotic and human influenza viruses and the development of novel antiviral agents with different targets should be continued., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Hemagglutinin (HA) and neuraminidase (NA) are major glycoproteins expressed on the surface of influenza virus. They have complementary and antagonistic functions that facilitate in the life cycle of the virus. The functional equilibrium generated between HA and NA can impact the evolution and adaptation of influenza virus strains within the human reservoir. This functional equilibrium is referred to as the "HA-NA balance". An imbalanced HA-NA can restrict the multiplication and transmission capacity of influenza viruses. Moreover, this equilibrium is likely a limiting factor against species crossover for the virus. In light of such considerations, the HA-NA balance should be precisely studied to gain a better understanding of the emergence of pandemic and seasonal influenza virus strains. This review describes the concept of the HA-NA balance, the methods used to study it, plus a discussion of the HA-NA balance in the evolution of the pandemic influenza A H1N1 strains that plagued the world in 1918 and 2009.

Unlabelled: α-Defensins produced by neutrophils are important effector molecules of the innate immune system. In addition to their microbicidal effects, α-defensins have the ability to neutralize bacterial toxins. Panton-Valentine leukocidin (PVL) is the hallmark of community-acquired methicillin-resistant Staphylococcus aureus. Staphylococcus aureus that produce PVL are responsible for severe diseases, including necrotizing pneumonia. Polymorphonuclear neutrophils (PMNs) are the target cells of PVL action. The goal of this study was to elucidate the effect of a group of α-defensins known as the human neutrophil peptides (HNPs) on the interactions between LukS-PV and LukF-PV, which compose PVL, and human PMNs. We observed that HNPs bound to both subunits of PVL and significantly decreased PVL pore formation in PMNs, with a maximum inhibition of 27%. When various HNP molecules were tested individually under the same conditions, we observed that HNP3, but not HNP1 or 2, decreased pore formation. Similarly, HNP3 significantly decreased PVL-induced PMN lysis, with a maximum inhibition of 31%. Interestingly, HNPs did not affect LukS-PV LukF-PV oligomerization, LukS-PV LukF-PV binding to PMNs or calcium influx induced by PVL in PMNs. Our results suggest that HNP3 partially protects neutrophils against PVL by interfering with the conformational changes of PVL required to form a functional pore., Significance and Impact of the Study: Panton-Valentine leukocidin (PVL) is a pore-forming toxin produced by Staphylococcus aureus, responsible for neutrophil damage and key player of severe staphylococcal diseases. Antimicrobial peptides produced by neutrophils (HNP1-3) neutralize several other bacterial cytotoxins. We examined the impact of human neutrophil peptides (HNPs) on PVL cytotoxicity against human neutrophils and we found that HNPs bind to both LukS and LukF components of PVL, thereby inhibiting pore formation and neutrophil lysis. Our results suggest that HNP3 may impair PVL conformational changes required to form a functional pore and provide insight into the pathogenesis of PVL-related staphylococcal infection, with potential impact on the disease outcome., (© 2015 The Society for Applied Microbiology.)

Objective: Co-expression of p16INK4a protein and Ki-67 (p16/Ki-67) is noted in almost all high-grade urothelial lesions. However, the aetiological role or, conversely, the absence of causative effect of high-risk human papillomaviruses (hr-HPVs) has not been documented. The purpose of this study is to evaluate HPV DNA in p16/Ki-67-positive, high-grade urothelial tumour cells., Methods: Fifty-seven urine samples collected from 50 patients, including 55 histologically proven high-grade proliferations and two cases with clinical evidence of malignancy, were analysed for p16/Ki-67. Immunolabelling was performed in destained Papanicolaou-stained slides after ThinPrep(®) processing. HPV genotyping was performed by polymerase chain reaction (PCR) using a DNA microarray for 35 HPV types. Confirmation of the presence (or absence) of HPV in tissue samples was verified using a reasoned approach combining PCR and in situ hybridization (ISH) for hr-HPVs., Results: Co-expression of p16/Ki-67 was noted in 43 of 57 (75.4%) cases. In these, hr-HPVs 16, 31 and 70, and low risk HPV 84, were detected in the urine in four patients (8%). Upregulation of p16INK4a protein was confirmed on bladder biopsy or transurethral resection specimens, but PCR and ISH for hr-HPVs were both negative on the tissue sections., Conclusion: Our results show a low prevalence of HPV infection in the urinary tract of patients with p16/Ki-67-positive urothelial malignancy. The study confirms that the deregulated cell cycle, as demonstrated by p16/Ki-67 dual labelling, is independent of the oncogenic action of hr-HPVs in high-grade urothelial proliferations., (© 2014 John Wiley & Sons Ltd.)

Objective: Contact patterns and microbiological data contribute to a detailed understanding of infectious disease transmission. We explored the automated collection of high-resolution contact data by wearable sensors combined with virological data to investigate influenza transmission among patients and healthcare workers in a geriatric unit., Design: Proof-of-concept observational study. Detailed information on contact patterns were collected by wearable sensors over 12 days. Systematic nasopharyngeal swabs were taken, analyzed for influenza A and B viruses by real-time polymerase chain reaction, and cultured for phylogenetic analysis., Setting: An acute-care geriatric unit in a tertiary care hospital., Participants: Patients, nurses, and medical doctors., Results: A total of 18,765 contacts were recorded among 37 patients, 32 nurses, and 15 medical doctors. Most contacts occurred between nurses or between a nurse and a patient. Fifteen individuals had influenza A (H3N2). Among these, 11 study participants were positive at the beginning of the study or at admission, and 3 patients and 1 nurse acquired laboratory-confirmed influenza during the study. Infectious medical doctors and nurses were identified as potential sources of hospital-acquired influenza (HA-Flu) for patients, and infectious patients were identified as likely sources for nurses. Only 1 potential transmission between nurses was observed., Conclusions: Combining high-resolution contact data and virological data allowed us to identify a potential transmission route in each possible case of HA-Flu. This promising method should be applied for longer periods in larger populations, with more complete use of phylogenetic analyses, for a better understanding of influenza transmission dynamics in a hospital setting.

The widespread use of acyclovir (ACV) and the increasing number of immunocompromised patients have raised concern about an increase in ACV-resistant herpes simplex virus (HSV). ACV resistance has traditionally been a major concern for immunocompromised patients with a frequency reported between 2.5% and 10%. The aim of this study was to reassess the status of HSV resistance to ACV in immunocompetent and immunocompromised patients over a ten year period, between 2002 and 2011. This was done by retrospectively following 1425 patients. In immunocompetent patients, prevalence of resistance did not exceed 0.5% during the study period; whereas in immunocompromised patients, a significant increase was observed, rising from 3.8% between 2002 and 2006 (7/182 patients) to 15.7% between 2007 and 2011 (28/178) (p=0.0001). This sharp rise in resistance may largely be represented by allogeneic hematopoietic stem cell transplant patients, in which the prevalence of ACV resistance rose similarly from 14.3% (4/28) between 2002 and 2006 to 46.5% (26/56) between 2007 and 2011 (p=0.005). No increase in ACV resistance was detected in association with other types of immune deficiencies. Genotypic characterization of HSV UL23 thymidine kinase and UL30 DNA polymerase genes revealed 11 and 7 previously unreported substitutions, respectively. These substitutions may be related to potential polymorphisms, drug resistance, or other mutations of unclear significance., (Copyright © 2014 Elsevier B.V. All rights reserved.)