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Introduction. The traditional surveillance system for influenza and ARVI provides a general description of epidemics, but does not provide information on the age-related characteristics of the etiology and clinical peculiarities of severe acute respiratory diseases (SARI) in hospitalized patients. Aim. To monitor the etiology of SARI in hospitalized children and adults, assessing the impact of the COVID-19 pandemic on this process. Materials and methods. Standardized clinical and laboratory monitoring of SARI among 18,458 hospitalized patients was carried out in hospitals in three cities of Russia with weekly PCR detection of 11 types of pathogens. Results. According to the investigation of hospitalized patients with SARI for the period from 2018 to 2023, the viral etiology of respiratory diseases was deciphered in 58.3% of cases. Weekly monitoring showed a change in the etiological mosaic of SARI pathogens during the SARS-CoV-2 pandemic with a sharp decrease in the frequency of detection of influenza and respiratory syncytial virus (RSV) during the 2020–2021 season against the background of a significant increase of metapneumovirus and rhinovirus infections in children. During the 2022-2023 season an increase in the proportion of RSV infection in children under 6 years of age (up to 36.2%) was noted against the background of a significant decrease in the frequency of SARS-CoV-2. In the intensive care units (ICU), RSV infection was most often in children during the post-pandemic period (up to 30.1–53.6% of positive cases, p 0.001); in adults, SARS-CoV-2 was mostly detected (76,5–100% of cases, p 0.001). Conclusion. Hospital surveillance data significantly complements the epidemiological information obtained in the traditional surveillance system. Monitoring of infections has shown a continuously changing etiological infrastructure of SARI, with the disappearance of influenza and RSV during the COVID-19 pandemic and their return to circulation in the post-pandemic period.

Although the omicron variant of SARS-CoV-2 circulated intensely during the 2021–2022 season, many patients with severe acute respiratory disease tested negative for COVID-19. The aim of this study was to assess the presence of different respiratory viruses in deceased persons. The proportion of deceased persons with respiratory viral infections in the 2021–2022 season in Navarre, Spain, was estimated considering all deaths caused by confirmed COVID-19 according to the epidemiological surveillance and the results of multiplex PCR tests for respiratory viruses performed in a sample of deceased persons with a cause of death other than COVID-19. Of 3578 deaths, 324 (9.1%) were initially reported as caused by pre-mortem confirmed COVID-19. A sample of 242 persons who died by causes other than COVID-19 were tested post-mortem; 64 (26.4%) of them were positive for any respiratory virus: 11.2% for SARS-CoV-2, 5.8% for rhinovirus, 3.7% for human coronavirus, 2.5% for metapneumovirus, 1.7% for respiratory syncytial virus, 1.7% for parainfluenza, 1.2% for influenza, and less than 1% each for adenovirus and bocavirus. Combining both approaches, we estimated that 34.4% of all deceased persons during the study period had a respiratory viral infection and 19.2% had SARS-CoV-2. Only 33.3% (9/27) of SARS-CoV-2 and 5.0% (2/40) of other viruses detected post-mortem had previously been confirmed pre-mortem. In a period with very intense circulation of SARS-CoV-2 during the pandemic, other respiratory viruses were also frequently present in deceased persons. Some SARS-CoV-2 infections and most other viral infections were not diagnosed pre-mortem. Several respiratory viruses may contribute to excess mortality in winter. [ABSTRACT FROM AUTHOR]

We measured concentrations of SARS-CoV-2, influenza A and B virus, respiratory syncytial virus (RSV), mpox virus, human metapneumovirus, norovirus GII, and pepper mild mottle virus nucleic acids in wastewater solids at twelve wastewater treatment plants in Central California, USA. Measurements were made daily for up to two years, depending on the wastewater treatment plant. Measurements were made using digital droplet (reverse-transcription-) polymerase chain reaction (RT-PCR) following best practices for making environmental molecular biology measurements. These data can be used to better understand disease occurrence in communities contributing to the wastewater.

Background: While influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) are recognised as a cause of severe illness and mortality, clinical interest for respiratory syncytial virus (RSV), rhinovirus and human metapneumovirus (hMPV) infections is still limited. Methods: We conducted a retrospective database study comparing baseline characteristics and 30‐day mortality in a large cohort of adult patients admitted for an overnight stay or longer with an influenza virus (A/B), rhinovirus, hMPV, RSV or SARS‐CoV‐2 infection. For non‐SARS‐CoV‐2 viruses, data were included for the period July 2017–February 2020. For SARS‐CoV‐2, data between March 2020 and March 2022 were included. Results: Covariate‐adjusted 30‐day mortality following RSV, hMPV or rhinovirus infections was substantial (crude mortality 8–10%) and comparable with mortality following hospitalisation with an influenza A virus infection. Mortality following a SARS‐CoV‐2 infection was consistently higher than for any other respiratory virus, at any point in time (crude mortality 14–25%). Odds of mortality for SARS‐CoV‐2 compared with influenza A declined from 4.9 to 1.7 over the course of the pandemic. Patients with SARS‐CoV‐2 infection had less comorbidity than patients with other respiratory virus infections and were more often male. In this cohort, age was related to mortality following hospitalisation, while an association with comorbidity was not apparent. Conclusions: With the exception of SARS‐CoV‐2 infections, we find the clinical outcome of common respiratory virus infections requiring hospitalisation more similar than often assumed. The observed mortality from SARS‐CoV‐2 was significantly higher, but the difference with other respiratory viruses became less distinct over time. [ABSTRACT FROM AUTHOR]

Human metapneumovirus (hMPV) is a major respiratory pathogen worldwide. Here, we report the crystal structure of a neutralizing antibody M8C10 isolated from human B cells that targets the viral fusion protein (hMPV-F) trimerization interface. This is a novel prefusion-specific epitope that is highly conserved across hMPV strains and other related viruses. The interactions between M8C10 and hMPV-F are largely driven by residues on the light chain with most hypermutated light chain residues on or near the interface. This highlights the immune recognition of a buried trimerization interface during the in vivo affinity maturation process. In addition, in vivo cotton rat challenge studies were performed that show M8C10 provides strong lung protection against hMPV A viral challenge. The hMPV-F:M8C10 Fab structure reported reveals a class of hMPV antibodies in the human immune repertoire with a novel neutralization mechanism, targeting the trimerization interface of hMPV-F antigen. [ABSTRACT FROM AUTHOR]

Among the respiratory pathogens of birds, the Avian Metapneumovirus (aMPV) is one of the most relevant, as it is responsible for causing infections of the upper respiratory tract and may induce respiratory syndromes. aMPV is capable of affecting the reproductive system of birds, directly impacting shell quality and decreasing egg production. Consequently, this infection can cause disorders related to animal welfare and zootechnical losses. The first cases of respiratory syndromes caused by aMPV were described in the 1970s, and today six subtypes (A, B, C, D, and two more new subtypes) have been identified and are widespread in all chicken and turkey-producing countries in the world, causing enormous economic losses for the poultry industry. Conventionally, immunological techniques are used to demonstrate aMPV infection in poultry, however, the identification of aMPV through molecular techniques helped in establishing the traceability of the virus. This review compiles data on the main aMPV subtypes present in different countries; aMPV and bacteria co-infection; vaccination against aMPV and viral selective pressure, highlighting the strategies used to prevent and control respiratory disease; and addresses tools for viral diagnosis and virus genome studies aiming at improving and streamlining pathogen detection and corroborating the development of new vaccines that can effectively protect herds, preventing viral escapes. [ABSTRACT FROM AUTHOR]

BackgroundThe non-pharmaceutical measures in the first Covid-19 winter season significantly impacted respiratory pathogens such as RSV, influenza, or metapneumovirus, which cause respiratory infections, especially in infants and young children. This longitudinal prospective study aimed to determine how less strict measures affect the pathogen profile in the second winter season.MethodsFrom September 2021 till the end of March 2022, 678 children (0–36 months) admitted to Vienna's largest pediatric center with an acute respiratory infection were enrolled in this study. The researchers performed nasal swabs and tested them by multiplex PCR for 23 respiratory pathogens, chronicled clinical features and treatment, and analyzed the effect of lockdown on the pathogen prevalence.ResultsThe 815 smears of 678 children revealed the most common pathogens to be rhino-/enterovirus (38.5%), RSV (26.7%), and metapneumovirus (7.2%). The lockdown interrupted the early RSV onset in September [RR 0.367, CI (0.184–0.767), p = 0.003], while no effects on the other pathogens were found. Metapneumovirus started circulating in January. Influenza was only sporadically detected. The hospitalization rate was significantly higher than last season due to RSV [OR 4.089, 95%CI (1.414–11.827), p-adj = 0.05].ConclusionWith more flexible non-pharmaceutical measures, children aged 0–36 months started presenting again with viral pathogens, such as RSV and metapneumovirus. RSV, associated with a high hospitalization rate, had a very early onset with an abrupt interruption due to the only lockdown.

Avian metapneumovirus (AMPV) represents a long‐term threat to the poultry industry due to its etiological role in the induction of acute respiratory disease and/or egg drop syndrome in domestic turkeys, chickens, and ducks. Although this disease is commonly referred to as turkey rhinotracheitis, the host range of AMPV encompasses many avian species. We have screened 1323 oropharyngeal‐ and cloacal swab samples obtained from wild mallards in the Netherlands from 2017 to 2019 by RT‐PCR using a degenerate primer pair to detect all members of the Paramyxoviridae and Pneumoviridae or an avian metapneumovirus subtype C (AMPV‐C)‐specific RT‐qPCR assay. We identified a total of seven cases of AMPV‐C infections in wild, healthy mallards (Anas platyrhynchos), of which two AMPV‐C positive samples were further processed using next‐generation sequencing. Phylogenetic analysis of the two complete genomes showed that the newly identified AMPV‐C strains share closest sequence identity (97%) with Eurasian lineage AMPV‐C strains identified in Muscovy ducks in China that presented with severe respiratory disease and egg production loss in 2011. Further analysis of G protein amino acid sequences showed a high degree of variability between the newly identified AMPV‐C variants. PONDR scoring of the G protein has revealed the ectodomain of AMPV‐C to be partitioned into a long intrinsically disordered and short ordered region, giving insights into AMPV G protein structural biology. In summary, we provide the first report of full‐length AMPV‐C genome sequences derived from wild birds in Europe. This emphasizes the need for further surveillance efforts to better characterize the host range, epidemiologic distribution, and pathogenicity of AMPV‐C to determine the risk posed by cross‐species jumps from wildfowl to domesticated avian species. [ABSTRACT FROM AUTHOR]

Among the respiratory pathogens of birds, the Avian Metapneumovirus (aMPV) is one of the most relevant, as it is responsible for causing infections of the upper respiratory tract and may induce respiratory syndromes. aMPV is capable of affecting the reproductive system of birds, directly impacting shell quality and decreasing egg production. Consequently, this infection can cause disorders related to animal welfare and zootechnical losses. The first cases of respiratory syndromes caused by aMPV were described in the 1970s, and today six subtypes (A, B, C, D, and two more new subtypes) have been identified and are widespread in all chicken and turkey-producing countries in the world, causing enormous economic losses for the poultry industry. Conventionally, immunological techniques are used to demonstrate aMPV infection in poultry, however, the identification of aMPV through molecular techniques helped in establishing the traceability of the virus. This review compiles data on the main aMPV subtypes present in different countries; aMPV and bacteria co-infection; vaccination against aMPV and viral selective pressure, highlighting the strategies used to prevent and control respiratory disease; and addresses tools for viral diagnosis and virus genome studies aiming at improving and streamlining pathogen detection and corroborating the development of new vaccines that can effectively protect herds, preventing viral escapes.

We detected human metapneumovirus (HMPV) in 54 (5%) of 1055 children aged 5 to 13 years with acute respiratory illness (ARI) identified by outpatient and emergency department surveillance between November and May 2003-2009. Its clinical features were similar to those of HMPV-negative ARI, except a diagnosis of pneumonia was more likely (13% vs 4%, respectively; P = .005) and a diagnosis of pharyngitis (7% vs 24%, respectively; P = .005) was less likely in patients with HMPV- positive ARI than those with HMPV-negative ARI.

Background: Outbreaks cause significant morbidity and mortality in healthcare settings. Current testing methods can identify specific viral respiratory pathogens, yet the approach to outbreak management remains general. Objectives: Our aim was to examine pathogen-specific trends in respiratory outbreaks, including how attack rates, case fatality rates and outbreak duration differ by pathogen between hospitals and long-term care (LTC) and retirement homes (RH) in Ontario. Methods: Confirmed respiratory outbreaks in Ontario hospitals and LTC/RH reported between September 1, 2007, and August 31, 2017, were extracted from the integrated Public Health Information System (iPHIS). Median attack rates and outbreak duration and overall case fatality rates of pathogen-specific outbreaks were compared in both settings. Results: Over the 10-year surveillance period, 9,870 confirmed respiratory outbreaks were reported in Ontario hospitals and LTC/RH. Influenza was responsible for most outbreaks (32% in LTC/RH, 51% in hospitals), but these outbreaks were shorter and had lower attack rates than most non-influenza outbreaks in either setting. Human metapneumovirus, while uncommon (

Contexte : Les éclosions provoquent une morbidité et une mortalité importantes dans les établissements de soins de santé. Les méthodes de dépistage actuelles permettent de cerner des agents pathogènes respiratoires viraux spécifiques, mais l’approche de la gestion des éclosions reste générale. Objectifs : Notre objectif était d’examiner les tendances spécifiques aux agents pathogènes dans les éclosions respiratoires, y compris la façon dont le taux d’attaque, le taux de létalité et la durée de l’éclosion diffèrent par agent pathogène entre les hôpitaux, et les établissements de soins de longue durée et les maisons de retraite en Ontario. Méthodes : Les éclosions d’infections respiratoires confirmées dans les hôpitaux et les établissements de soins de longue durée ou les maisons de retraite de l’Ontario signalées entre le 1er septembre 2007 et le 31 août 2017 ont été extraites du Système intégré d’information sur la santé publique (SIISP). Les taux d’attaque médians, la durée des éclosions et les taux généraux de létalité des éclosions spécifiques à un pathogène ont été comparés dans les deux types d’établissements. Résultats : Au cours de la période de surveillance de 10 ans, 9 870 éclosions respiratoires confirmées ont été signalées dans les hôpitaux et les établissements de soins de longue durée ou les maisons de retraite de l’Ontario. La grippe était à l’origine de la plupart des éclosions (32 % dans les établissements de soins de longue durée et les maisons de retraite, 51 % dans les hôpitaux), mais ces éclosions étaient plus courtes et présentaient des taux d’attaque inférieurs à ceux de la plupart des éclosions non grippales dans les deux types d’établissements. Le métapneumovirus humain, bien que peu fréquent (moins de 4 % des éclosions), présentait des taux de létalité élevés dans les deux types d’établissements. Conclusion : Les taux d’attaque et les taux de létalité variaient selon l’agent pathogène, tout comme la durée de l’éclosion. L’élaboration de conseils propres à la gestion des éclosions, qui tiennent compte de l’agent pathogène et de l’établissement de soins de santé, pourrait être utile pour limiter la charge des éclosions respiratoires.

A 67-year-old man presented with a week of flu-like symptoms, hypoxia, and fever. Respiratory viral panel was positive for human metapneumovirus. Initial chest imaging showed left lower lobe opacification, suggesting a bacterial superimposed on viral pneumonia. Despite antibiotics, the patient became tachycardic and increasingly hypoxic, requiring 40 L high-flow nasal cannula. Repeat imaging demonstrated worsening of a left lower lobe process. Elective bronchoscopy with bronchoalveolar lavage revealed hemorrhage. Subsequent autoimmune, bacterial, and fungal workup was negative. The patient was diagnosed with diffuse alveolar hemorrhage (DAH) secondary to human metapneumovirus pneumonia. DAH is defined as bleeding into the alveolar spaces of the lungs, a process which carries high rates of morbidity and mortality.1 While dramatic in name and often associated with hemoptysis, DAH may only present with clinically subtle and nonspecific features with a variety of alternative etiologies to consider. We present this case of DAH secondary to human metapneumovirus (hMPV) to promote discussion of etiologies of DAH aside from systemic vasculitis. [ABSTRACT FROM AUTHOR]

Viruses cause a wide spectrum of clinical disease, the majority being acute respiratory infections (ARI). In most cases, ARI symptoms are similar for different viruses although severity can be variable. The objective of this study was to understand the shared and unique elements of the host transcriptional response to different viral pathogens. We identified 162 subjects in the US and Sri Lanka with infections due to influenza, enterovirus/rhinovirus, human metapneumovirus, dengue virus, cytomegalovirus, Epstein Barr Virus, or adenovirus. Our dataset allowed us to identify common pathways at the molecular level as well as virus-specific differences in the host immune response. Conserved elements of the host response to these viral infections highlighted the importance of interferon pathway activation. However, the magnitude of the responses varied between pathogens. We also identified virus-specific responses to influenza, enterovirus/rhinovirus, and dengue infections. Influenza-specific differentially expressed genes (DEG) revealed up-regulation of pathways related to viral defense and down-regulation of pathways related to T cell and neutrophil responses. Functional analysis of entero/rhinovirus-specific DEGs revealed up-regulation of pathways for neutrophil activation, negative regulation of immune response, and p38MAPK cascade and down-regulation of virus defenses and complement activation. Functional analysis of dengue-specific up-regulated DEGs showed enrichment of pathways for DNA replication and cell division whereas down-regulated DEGs were mainly associated with erythrocyte and myeloid cell homeostasis, reactive oxygen and peroxide metabolic processes. In conclusion, our study will contribute to a better understanding of molecular mechanisms to viral infections in humans and the identification of biomarkers to distinguish different types of viral infections. [ABSTRACT FROM AUTHOR]

Abstract Background Human metapneumovirus (HMPV) is an important cause of acute respiratory illness in young children. Whole genome sequencing enables better identification of transmission events and outbreaks, which is not always possible with sub-genomic sequences. Results We report a 2-reaction amplicon-based next generation sequencing method to determine the complete genome sequences of five HMPV strains, representing three subgroups (A2, B1 and B2), directly from clinical samples. In addition to reporting five novel HMPV genomes from Africa we examined genetic diversity and sequence patterns of publicly available HMPV genomes. We found that the overall nucleotide sequence identity was 71.3 and 80% for HMPV group A and B, respectively, the diversity between HMPV groups was greater at amino acid level for SH and G surface protein genes, and multiple subgroups co-circulated in various countries. Comparison of sequences between HMPV groups revealed variability in G protein length (219 to 241 amino acids) due to changes in the stop codon position. Genome-wide phylogenetic analysis showed congruence with the individual gene sequence sets except for F and M2 genes. Conclusion This is the first genomic characterization of HMPV genomes from African patients.

La rinotraqueitis infecciosa bovina (IBR) es una enfermedad ampliamente difundida en el mundo con gran repercusión socio-económica en las ganaderías bovinas. El objetivo del presente estudio fue determinar la prevalencia de IBR en 100 hatos del departamento del Caquetá, para lo cual, se muestrearon 960 bovinos mayores de 36 meses entre enero y marzo de 2016 en predios seleccionados a partir de los criterios: a) tamaño (50-180 hectáreas), b) con más de 10 vacas en ordeño, c) disponibilidad de los productores para cooperar y d) accesibilidad de las vías. Las muestras de suero sanguíneo se remitieron al Laboratorio de Diagnóstico Clínico Veterinario del ICA y se analizaron a través la prueba Elisa de bloqueo (BHV-1) gB. Los sueros con porcentaje de bloqueo superior al 55% se consideraron positivos a anticuerpos para IBR. Se encontró alta seroprevalencia (73,13%), mayor además en machos que en hembras (p < 0,05). A nivel municipal la seroprevalencia fue mayor en los municipios de El Doncello, Puerto Rico y San Vicente del Caguán y se encontró diferencia significativa (p < 0,05) entre los nueve municipios analizados. A nivel de hatos, la prevalencia fue del 99%. En conclusión, la prevalencia del virus de la rinotraqueitis infecciosa bovina (IBR) en bovinos de doble propósito del departamento del Caquetá fue muy alta.

Background: Human Metapneumovirus (HMPV) belongs to the Pneumoviridae family and is responsible for respiratory infections. Mild infections are well-recognized in children, while its precise impact in various categories of immunocompromised adults has not been well addressed., Research Question: We retrospectively studied HMPV infections in immunocompromised adults followed in two large French university medical centers., Study Design and Methods: We identified immunocompromised adults with positive HMPV Polymerase Chain Reaction (PCR) for 36 months and reviewed their medical charts. For lung transplant recipients (LTR), FEV1 was collected at baseline, during and after infection. Imaging was centralized and chest involvement was categorized by dominant CT patterns. We compared severe patients (requiring oxygen or ventilation) and non hypoxemic patients., Results: Seventy-two patients were included, 27 were LTR, 25 had a hematological malignancy or were hematopoietic stem cell recipients, 20 had another immunocompromised status. Twenty patients (28%) presented a hypoxemic infection, requiring hospitalization and intensive care units transfers in 50/72 (69.4%) and 9/72 (12.5%) respectively, with only one death. Hypoxemia was less pronounced in LTRs (p = 0.014). Finally, age and dyspnea remained independent factors associated with hypoxemia (p < 0.005). The most frequent radiological patterns were bronchopneumonia (34.2%) and bronchiolitis (39.5% and 64.3% in the overall population and in LTRs respectively, p = 0.045). FEV1 improved in LTRs at one month and 85% had recovered their baseline FEV1 within 6 months., Interpretations: In immunocompromised adults, HMPV infections required frequent hospitalizations and ICU transfers, while mortality is low. In LTRs, bronchiolitis pattern was predominant with short and long-term favorable outcome., Competing Interests: Declaration of competing interest V.A.-F. has received grants (to her institution) from the ANRS, ViiV Healthcare and the MSD AVENIR foundation and honoraria and travel grants from ViiV Healthcare and Gilead Sciences, for participation in educational programs and conferences; Others authors do not have conflict of interest related to the present article., (Copyright © 2024. Published by Elsevier Ltd.)

We analyzed data from a community-based acute respiratory illness study involving K-12 students and their families in southcentral Wisconsin and assessed household transmission of two common seasonal respiratory viruses - human metapneumovirus (HMPV) and human coronaviruses OC43 and HKU1 (HCOV). We found secondary infection rates of 12.2% (95% CI: 8.1%-17.4%) and 19.2% (95% CI: 13.8%-25.7%) for HMPV and HCOV, respectively. We performed individual- and family-level regression models and found that HMPV transmission was positively associated age of the index case (individual model: p  = .016; family model: p  = .004) and HCOV transmission was positively associated with household density (family model: p  = .048). We also found that the age of the non-index case was negatively associated with transmission of both HMPV (individual model: p  = .049) and HCOV (individual model: p  = .041), but we attributed this to selection bias from the original study design. Understanding household transmission of common respiratory viruses like HMPV and HCOV may help to broaden our understanding of the overall disease burden and establish methods to prevent the spread of disease from low- to high-risk populations.

Objective: Many providers use severe acute respiratory coronavirus virus 2 (SARS-CoV-2) cycle thresholds (Ct values) as approximate measures of viral burden in association with other clinical data to inform decisions about treatment and isolation. We characterized temporal changes in Ct values for non-SARS-CoV-2 respiratory viruses as a first step to determine whether cycle thresholds could play a similar role in the management of non-SARS-CoV-2 respiratory viruses., Design: Retrospective cohort study., Setting: Brigham and Women's Hospital, Boston., Methods: We retrospectively identified all adult patients with positive nasopharyngeal PCRs for influenza, respiratory syncytial virus (RSV), parainfluenza, human metapneumovirus (HMPV), rhinovirus, or adenovirus between January 2022 and March 2023. We plotted Ct distributions relative to days since symptom onset, and we assessed whether distributions varied by immunosuppression and other comorbidities., Results: We analyzed 1,863 positive samples: 506 influenza, 502 rhinovirus, 430 RSV, 219 HMPV, 180 parainfluenza, 26 adenovirus. Ct values were generally 25-30 on the day of symptom onset, lower over the ensuing 1-3 days, and progressively higher thereafter with Ct values ≥30 after 1 week for most viruses. Ct values were generally higher and more stable over time for rhinovirus. There was no association between immunocompromised status and median intervals from symptom onset until Ct values were ≥30., Conclusions: Ct values relative to symptom onset for influenza, RSV, and other non-SARS-CoV-2 respiratory viruses generally mirror patterns seen with SARS-CoV-2. Further data on associations between Ct values and viral viability, transmissibility, host characteristics, and response to treatment for non-SARS-CoV-2 respiratory viruses are needed to determine how clinicians and infection preventionists might integrate Ct values into treatment and isolation decisions.

Background: Effects of non-pharmaceutical interventions during the pandemic were mainly studied for severe outcomes. Among children, most of the burden of respiratory infections is related to infections which are not medically attended. The perspective on infections in the community setting is necessary to understand the effects of the pandemic on non-pharmaceutical interventions., Methods: In the unique prospective LoewenKIDS cohort study, we compared the true monthly incidence of self-reported acute respiratory infections (ARI) in about 350 participants (aged 3-4 years old) between October 2019 to March 2020 (pre-pandemic period) and October 2020 to March 2021 (pandemic period). Parents reported children's symptoms using a diary. Parents were asked to take a nasal swab of their child during all respiratory symptoms. We analysed 718 swabs using Multiplex PCR for 25 common respiratory viruses and bacteria., Results: During the pre-pandemic period, on average 44.6% (95% CI: 39.5-49.8%) of children acquired at least one ARI per month compared to 19.9% (95% CI: 11.1-28.7%) during the pandemic period (Incidence Rate Ratio = 0.47; 95% CI: 0.41-0.54). The detection of influenza virus decreased absolute by 96%, respiratory syncytial virus by 65%, metapneumovirus by 95%, parainfluenza virus by 100%, human enterovirus by 96% and human bocavirus by 70% when comparing the pre-pandemic to the pandemic period. However, rhinoviruses were nearly unaffected by NPI. Co-detection (detection of more than one virus in a single symptomatic swab) was common in the pre-pandemic period (222 of 390 samples with viral detection; 56.9%) and substantially less common during the pandemic period (46 of 216 samples; 21.3%)., Conclusion: Non-pharmaceutical interventions strongly reduced the incidence of all respiratory infections in preschool children but did not affect rhinovirus., (© 2024. The Author(s).)

Background: Pneumonia is a leading cause of morbidity and mortality in children < 5 years. We describe nasopharyngeal carriage of respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and influenza virus among children with fast-breathing pneumonia in Karachi, Pakistan., Methods: We performed a cross-sectional analysis of nasopharyngeal swabs from children aged 2-59 months with fast-breathing pneumonia, enrolled in the randomized trial of amoxicillin versus placebo for fast-breathing pneumonia (RETAPP) (NCT02372461) from 2014 to 2016. Swabs were collected using WHO standardized methods, processed at the Aga Khan University, Pakistan. Viral detection was performed using LUMINEX xTAG respiratory viral panel assay and logistic regression identified clinical and sociodemographic predictors., Findings: Of the 1000 children tested, 92.2% (n = 922) were positive for viral carriage. RSV, hMPV, and influenza virus were detected in 59 (6.4%), 56 (6.1%), and 58 (6.3%) children and co-infections in three samples (two RSV-hMPV and one influenza-hMPV). RSV carriage was common in infants (56%), we observed a higher occurrence of fever in children with hMPV and influenza virus (80% and 88%, respectively) and fast breathing in RSV (80%) carriage. RSV carriage was positively associated with a history of fast/difficulty breathing (aOR: 1.96, 95% CI 1.02-3.76) and low oxygen saturation (aOR: 2.52, 95% CI 1.32-4.82), hMPV carriage was positively associated with a complete vaccination status (aOR: 2.22, 95% CI 1.23-4.00) and body temperature ≥ 37.5°C (aOR: 2.34, 95% CI 1.35-4.04) whereas influenza viral carriage was associated with body temperature ≥ 37.5°C (aOR: 4.48, 95% CI 2.53-7.93)., Conclusion: We observed a high nasopharyngeal viral carriage among children with WHO-defined fast-breathing pneumonia in Pakistan. Fever, difficulty in breathing, hypoxia and vaccination status are important clinical predictors for viral nonsevere community-acquired pneumonia., (© 2024 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

We compared the epidemiology, severity and management of hospitalized respiratory syncytial virus (n = 305) and human metapneumovirus (n = 39) bronchiolitis in a setting with high respiratory virus testing (95% of admissions tested). Respiratory syncytial virus-positive infants were younger and tended to require more hydration support and longer hospital stays compared to human metapneumovirus-positive infants. Respiratory support requirements were similar between groups despite significant age differences., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

We assessed human metapneumovirus infections in children hospitalized between 2011 and 2023 and compared the strongest pre- and postpandemic seasons. After the COVID-19 pandemic, we observed offseason cases and loss of the alternating pattern of the human metapneumovirus season magnitude. Incidence rate ratio of 0- to 11-month-old versus 12- to 23-month-old children was 2.1 (95% CI: 1.0-4.8) before and 1.3 (95% CI: 0.6-2.9) after the pandemic., Competing Interests: R.S., V.M., I.K., and C.A. have no conflicts of interest to disclose. P.L. reports grants from Vertex and OM Pharma paid to the institution; personal payments or honoraria from Vertex, Vifor and OM Pharma; all outside the submitted work. P.A. reports honoraria from Sanofi paid to the institution outside the submitted work., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)