BACKGROUND: Redondoviridae is a newly discovered virus family linked to oral and respiratory conditions in people, while there is still debate about whether it is also coinfected with other respiratory viruses. This study aimed to determine the frequency of Redondovirus (ReDoV) in nasopharyngeal samples and to investigate any possible links to SARS-CoV-2 infections.
METHODS: A polymerase chain reaction (PCR) test was conducted on 731 nasopharyngeal samples from individuals referred to medical centers in Tehran, Iran, for SARS-CoV-2 testing to investigate the prevalence of ReDoV. An oral interview was performed to complete information on dental issues and the individuals\' demographics, symptoms, and vaccination history.
RESULTS: The prevalence of ReDoV was 25.99%, and 15.26% had a coinfection with SARS-CoV-2. No notable correlation was found regarding ReDoVs and SARS-CoV-2 infections (p > 0.05). Women had a higher ReDoV positivity rate of 18.47% compared to men at 7.52% (p = 0.12), and there was no significant correlation between age groups and ReDoV presence. Nonetheless, a significant association was noted between ReDoVs and dental/gum issues (p < 0.0001, OR: 13.0326). A phylogenetic analysis showed that ReDoVs originated from various human-related clusters.
CONCLUSIONS: These results highlight the potential for detecting ReDoVs in nasopharyngeal samples of people with gum or dental issues. Additionally, conducting more ReDoV epidemiological research and proposing oral health as a possible marker for ReDoV infections is important.

BACKGROUND: The FilmArray Respiratory Panel RP 2.1 plus (FilmArray RP) is a point-of-care syndromic panel for respiratory pathogens. Although highly valuable in the clinical settings, the co-detection of pathogens in FilmArray RP may confound result interpretation.
METHODS: Nasopharyngeal swab specimens collected from patients with respiratory symptoms were analyzed by comparing co-detection results from FilmArray RP with those of Allplex Respiratory Panels (Allplex RP: Power-Chek for SARS-CoV-2).
RESULTS: Out of 765 FilmArray RP tests, 143 (18.7%) showed co-detections (two: 122 (85.3%), three: 18 (12.6%), four: 2 (1.4%), and five viruses: 1 (0.7%). The most frequent co-detection was human rhinovirus/enterovirus (HRV/HEV) with respiratory syncytial virus (RSV) (22.3%, 32/143). The overall discordance rate between Film-Array RP and other tests was 32.9%. Notably, discordance in detecting adenovirus (AdV) was significant, with cases detected by FilmArray often not appearing in Allplex RP.
CONCLUSIONS: Discordances were varied by virus combination. It is advisable to perform additional confirmatory testing based on clinical relevance.

Studies during the COVID-19 pandemic showed that children had heightened nasal innate immune responses compared with adults. To evaluate the role of nasal viruses and bacteria in driving these responses, we performed cytokine profiling and comprehensive, symptom-agnostic testing for respiratory viruses and bacterial pathobionts in nasopharyngeal samples from children tested for SARS-CoV-2 in 2021-22 (n = 467). Respiratory viruses and/or pathobionts were highly prevalent (82% of symptomatic and 30% asymptomatic children; 90 and 49% for children <5 years). Virus detection and load correlated with the nasal interferon response biomarker CXCL10, and the previously reported discrepancy between SARS-CoV-2 viral load and nasal interferon response was explained by viral coinfections. Bacterial pathobionts correlated with a distinct proinflammatory response with elevated IL-1β and TNF but not CXCL10. Furthermore, paired samples from healthy 1-year-olds collected 1-2 wk apart revealed frequent respiratory virus acquisition or clearance, with mucosal immunophenotype changing in parallel. These findings reveal that frequent, dynamic host-pathogen interactions drive nasal innate immune activation in children.

Haemophilus influenzae serotype a (Hia) has recently emerged as an important cause of invasive disease in the North American Arctic and Sub-Arctic regions, mainly affecting young Indigenous children. In this study, we addressed the question of whether the prevalence of Hia and all H. influenzae in the nasopharynx differed between paediatric populations from regions with high versus low incidence of invasive Hia disease. Nasopharyngeal specimens from children with acute respiratory tract infections (ARTI) collected for routine diagnostic detection of respiratory viruses were analysed with molecular-genetic methods to identify and serotype H. influenzae. In Nunavut, a region with a high incidence of invasive Hia disease, all H. influenzae and particularly Hia were found in the nasopharynx of 60.6% and 3.0% children. In Southern Ontario (Hamilton region), where Hia invasive disease is rare, the frequencies of all H. influenzae and Hia detection were 38.5% and 0.6%, respectively. In both cohorts, non-typeable H. influenzae was prevalent (57.0% and 37.9%, respectively). Considering that Hia is an important cause of severe invasive disease in Nunavut children, 3% prevalence of Hia among children with ARTI can reflect continuing circulation of the pathogen in the Northern communities that may result in invasive disease outbreaks.

OBJECTIVE: Postnasal drip may be related to several diseases, but not all patients are clearly diagnosed. Patients with chronic, idiopathic postnasal drip symptoms are easily overlooked, and their clinical features are yet to be identified. This study aimed to analyze the clinical features and response to first generation antihistamine-decongestant therapy in patients with chronic idiopathic postnasal drip, suggesting it as a distinct entity.
METHODS: A retrospective cohort study involving 157 chronic idiopathic postnasal drip patients was conducted, analyzing demographics, symptoms, and treatment response to first-generation antihistamines and nasal decongestants.
RESULTS: Mean age of patients was 55.4±17.0 years old. Median duration of symptom was 36 months (range=12-66 months) and severity in the visual analogue scale was 7 (range=5-8). Throat discomfort was the most frequently associated symptom (73.7%). Cough was recorded in 30.3% of patients. Viscosity of postnasal drip was associated with rhinorrhea and throat discomfort. Of the patients, 71.6% responded positively to 1st generation antihistamine-decongestant medication. However, 25.9% of patients presented symptom re-occurrence. Patients with nasal stiffness or persistent symptoms presented a higher re-occurrence rate compared to others.
CONCLUSIONS: This study outlines the clinical features of patients with chronic idiopathic postnasal drip and suggests it as a distinctive entity., This proposal aims to enhance diagnostic precision and promote further research in the field.

This study aimed to determine the incidence and etiological, seasonal, and genetic characteristics of respiratory viral coinfections involving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Between October 2020 and January 2024, nasopharyngeal samples were collected from 2277 SARS-CoV-2-positive patients. Two multiplex approaches were used to detect and sequence SARS-CoV-2, influenza A/B viruses, and other seasonal respiratory viruses: multiplex real-time polymerase chain reaction (PCR) and multiplex next-generation sequencing. Coinfections of SARS-CoV-2 with other respiratory viruses were detected in 164 (7.2%) patients. The most common co-infecting virus was respiratory syncytial virus (RSV) (38 cases, 1.7%), followed by bocavirus (BoV) (1.2%) and rhinovirus (RV) (1.1%). Patients ≤ 16 years of age had the highest rate (15%) of mixed infections. Whole-genome sequencing produced 19 complete genomes of seasonal respiratory viral co-pathogens, which were subjected to phylogenetic and amino acid analyses. The detected influenza viruses were classified into the genetic groups 6B.1A.5a.2a and 6B.1A.5a.2a.1 for A(H1N1)pdm09, 3C.2a1b.2a.2a.1 and 3C.2a.2b for A(H3N2), and V1A.3a.2 for the B/Victoria lineage. The RSV-B sequences belonged to the genetic group GB5.0.5a, with HAdV-C belonging to type 1, BoV to genotype VP1, and PIV3 to lineage 1a(i). Multiple amino acid substitutions were identified, including at the antibody-binding sites. This study provides insights into respiratory viral coinfections involving SARS-CoV-2 and reinforces the importance of genetic characterization of co-pathogens in the development of therapeutic and preventive strategies.

The evolution of SARS-CoV-2, the agent of COVID-19, has been remarkable for its high mutation potential, leading to the appearance of variants. Some mutations have never appeared in the published genomes, which represent consensus, or bona fide genomes. Here we tested the hypothesis that mutations that did not appear in consensus genomes were, in fact, as frequent as the mutations that appeared during the various epidemic episodes, but were not expressed because lethal. To identify these mutations, we analysed the genomes of 90 nasopharyngeal samples and the quasispecies determined by next-generation sequencing. Mutations observed in the quasispecies and not in the consensus genomes were considered to be lethal, what we called \"outlaw\" mutations. Among these mutations, we analysed the 21 most frequent. Eight of these \"outlaws\" were in the RNA polymerase and we were able to use a structural biology model and molecular dynamics simulations to demonstrate the functional incapacity of these mutated RNA polymerases. Three other mutations affected the spike, a major protein involved in the pathogenesis of COVID-19. Overall, by analysing the SARS-CoV-2 quasispecies obtained during sequencing, this method made it possible to identify \"outlaws,\" showing areas that could potentially become the target of treatments.

In 2020, there were numerous cases in Kazakhstan with clinical symptoms of COVID-19 but negative PCR results in nasopharyngeal and oropharyngeal swabs. The diagnosis was confirmed clinically and by CT scans (computed tomography). The problem with such negative PCR results for SARS-CoV-2 infection confirmation still exists and indicates the need to confirm the diagnosis in the bronchoalveolar lavage in such cases. There is also a lack of information about confirmation of SARS-CoV-2 infection in deceased patients. In this study, various tissue materials, including lungs, bronchi, and trachea, were examined from eight patients who died, presumably from SARS-CoV-2 infection, between 2020 and 2022. Naso/oropharyngeal swabs taken from these patients in hospitals tested PCR negative for SARS-CoV-2. This study presents a modified RNA isolation method based on a comparison of the most used methods for RNA isolation in laboratories: QIAamp Viral RNA Mini Kit and TRIzol-based method. This modified nucleic acid extraction protocol can be used to confirm SARS-CoV-2 infection by RT-qPCR in the tissues of deceased patients in disputed cases. RT-qPCR with RNA of SARS-CoV-2 re-extracted with such method from post-mortem tissues that were stored at -80 °C for more than 32 months still demonstrated high-yielding positive results.

The COVID-19 pandemic is an ongoing global health threat, yet our understanding of the dynamics of early cellular responses to this disease remains limited1. Here in our SARS-CoV-2 human challenge study, we used single-cell multi-omics profiling of nasopharyngeal swabs and blood to temporally resolve abortive, transient and sustained infections in seronegative individuals challenged with pre-Alpha SARS-CoV-2. Our analyses revealed rapid changes in cell-type proportions and dozens of highly dynamic cellular response states in epithelial and immune cells associated with specific time points and infection status. We observed that the interferon response in blood preceded the nasopharyngeal response. Moreover, nasopharyngeal immune infiltration occurred early in samples from individuals with only transient infection and later in samples from individuals with sustained infection. High expression of HLA-DQA2 before inoculation was associated with preventing sustained infection. Ciliated cells showed multiple immune responses and were most permissive for viral replication, whereas nasopharyngeal T cells and macrophages were infected non-productively. We resolved 54 T cell states, including acutely activated T cells that clonally expanded while carrying convergent SARS-CoV-2 motifs. Our new computational pipeline Cell2TCR identifies activated antigen-responding T cells based on a gene expression signature and clusters these into clonotype groups and motifs. Overall, our detailed time series data can serve as a Rosetta stone for epithelial and immune cell responses and reveals early dynamic responses associated with protection against infection.

The aim of this study was to investigate the epidemiological characteristics of respiratory syncytial virus (RSV) infections in children in Zhejiang from 2019 to 2023. Data from pediatric patients who visited the Children\'s Hospital of Zhejiang University School of Medicine for RSV infection between 2019 and 2023 were analyzed. Nasopharyngeal swabs were collected for RSV antigen detection, and relevant patient information was collected. Factors such as age were analyzed. A total of 673 094 specimens were included from 2019 to 2023, with a rate of positive specimens of 4.74% (31 929/673 094). The highest rate of positive specimens of 10.82%, was recorded in 2021, while the remaining years had a rate of approximately 3%-5%. In terms of seasonal prevalence characteristics, the rate of positive specimens in 2019, 2020, and 2022 peaked in the winter months at approximately 8% and decreased in the summer months, where the rate of positive specimens remained at approximately 0.5%. In contrast, summer is the peak period for RSV incidence in 2021 and 2023, with the rate of positive specimens being as high as 9%-12%. Based on the prevalence characteristics of gender and age, this study found that the detection rate of positive specimens was higher in boys than in girls in 2019-2023. In 2019-2022, among the different age groups, the highest rate of positive specimens was found in children aged 0 to <6 months, and it decreased with age. In 2023, the rate of positive specimens was above 8% in the 0 to <6 months, 6 to <12 months, and 1-2 years age groups, with the highest rate of positive specimens in the 1-2 years age group, and a gradual decrease in the rate of positive specimens with age for children over 3 years of age. Between 2019 and 2023, the epidemiological pattern of RSV changed. A summer peak was observed in 2021 and 2023.