Background Persons experiencing homelessness face increased risk of influenza as overcrowding in congregate shelters can facilitate influenza virus spread. Data regarding on-site influenza testing and antiviral treatment within homeless shelters remains limited. Methods We conducted a cluster-randomized stepped-wedge trial of point-of-care molecular influenza testing coupled with antiviral treatment with baloxavir or oseltamivir in residents of 14 homeless shelters in Seattle, WA, USA. Residents ≥3 months with cough or ≥2 acute respiratory illness (ARI) symptoms and onset <7 days were eligible. In control periods, mid-nasal swabs were tested for influenza by RT-PCR. The intervention period included on-site rapid molecular influenza testing and antiviral treatment for influenza-positives if symptom onset was <48 hours. The primary endpoint was monthly influenza virus infections in the control versus intervention period. Influenza whole genome sequencing was performed to assess transmission and antiviral resistance. Results During 11/15/2019–4/30/2020, and 11/2/2020–4/30/2021, 1,283 ARI encounters from 668 participants were observed. Influenza virus was detected in 51 (4%) specimens using RT-PCR, (A=14; B=37); 21 influenza virus infections were detected from 269 (8%) of intervention-eligible encounters by rapid molecular testing and received antiviral treatment. 37% of ARI-participant encounters reported symptom onset <48 hours. The intervention had no effect on influenza virus transmission (adjusted relative risk 1.73, 95% CI 0.50–6.00). Of 23 influenza genomes, 86% of A(H1N1)pdm09 and 81% of B/Victoria sequences were closely related. Conclusion Our findings suggest feasibility of influenza test-and-treat strategies in shelters. Additional studies would help discern an intervention effect during periods of increased influenza activity

Background. Surveillance programmes for influenza and other respiratory pathogens are important to generate vaccine effectiveness (VE) estimates and to inform vaccine composition. We aimed to explore the feasibility and acceptability of home-based testing. Methods In 3/9 provinces in South Africa, we established a self-referral system for individuals aged ≥18 years with respiratory symptoms of ≤10 days duration. Following electronic consent, swab collection material was delivered to participants who also completed a questionnaire including self-reported vaccination status. Swabs were tested by PCR for influenza, respiratory syncytial virus (RSV) and SARS-CoV-2. A test negative methodology was used to estimate influenza VE. Results Of 1456 samples collected between 1 December 2021 and 31 August 2022, 73 (5%) tested positive for influenza, 38 (3%) tested positive for RSV and 394 (27%) for SARS-CoV-2. We subtyped 55% (40/73) of the influenza positive specimens; 16/40 (40%) were influenza A (A(H1N1)pdm09; 10/40 (25%)A (H3N2)) and all 14/40(35%) influenza B were B/Victoria. Only 20% (279/1451) of participants reported influenza-like illness case definition symptoms of fever and cough. Influenza vaccine coverage was 11% (157/1454). The overall influenza VE was 26% (95% confidence interval, -73%;69%). Of the completed acceptability questionnaires, 123/127 (97%) participants would make use of the service again. 36% (46/127) of enrolled participants were recruited through the testing centre’s webpage and 13% (17/127) through social media. Conclusions Home-based swabbing was feasible and acceptable. We were able to calculate an influenza VE, although a large sample size and verification of vaccine status may improve the VE estimate in the future.

Every year, influenza virus infections cause significant morbidity and mortality worldwide. They pose a substantial burden of disease, not only in terms of health but also economic-wise. Owing to the ability of influenza viruses to continuously evolve, annual seasonal influenza vaccines are necessary as a prophylaxis. However, current influenza vaccines against seasonal strains have limited effectiveness and require yearly reformulation due to the virus undergoing antigenic drift or shift. Vaccine mismatches are common, conferring suboptimal protection against seasonal outbreaks, and the threat of the next pandemic continues to loom. Therefore, there is a great need to develop a universal influenza vaccine (UIV) capable of providing broad and durable protection against all influenza virus strains. In the quest to develop a UIV that would obviate the need for annual vaccination and formulation, a multitude of strategies are currently underway. Promising approaches include targeting the highly conserved epitopes of hemagglutinin (HA), neuraminidase (NA), M2 extracellular domain (M2e), and internal proteins of the influenza virus. The identification and characterisation of broadly neutralising antibodies (bnAbs) targeting conserved regions of the viral HA protein, in particular, have provided important insight into novel vaccine designs and platforms. This review discusses universal vaccine approaches presently under development, with an emphasis on those targeting the highly conserved stalk of the HA protein, recent technological advancements used, and the future prospects of a UIV in terms of its advantages, developmental obstacles and potential shortcomings.

Background: Compelling evidence suggests associations between influenza infection and thromboembolism (TE) events. Risk factors related to the outcomes of severe influenza-complicated TE in intensive care unit (ICU) patients remain unknown. Methods: A retrospective cohort study was conducted, recruiting consecutive patients with thromboembolism (TE) events admitted to the intensive care unit (ICU) between December 2015 through December 2018 at our institution in Taiwan. A study cohort of patients with severe influenza (n=108) and a control group of patients with severe community-acquired pneumonia (n=192) were included. Associations between complicated TE, length of ICU stay, 90-day mortality were evaluated. Results: Thromboembolism events prevalence was significantly higher in ICU patients with severe influenza than in ICU patients with severe CAP (21.3% vs. 5.7%, respectively; p<0.05). The ratio of mechanical ventilation use, length of mechanical ventilation use, ICU stay and 90-day mortality increased significantly in ICU patients with severe influenza after developing TE compared with patients without TE (all p<0.05). Influenza infection and hypertension are the risk factors for thromboembolic events in patients with severe influenza (p< 0.05). Besides, complicated TE and severity of APACHE II score are risk factors for 90-day mortality in ICU patients with severe influenza (p< 0.05). Conclusions: ICU patients with severe influenza and complicated TE have an increased risk of extended ICU stay and 90-day mortality compared to patients with severe CAP. Risk is significantly increased in patients with higher APACHE II score. this study may help define better strategies for early recognition and prevention of severe influenza-complicated TE.

Background Older adults in nursing and care homes (NCHs) are vulnerable to severe respiratory syncytial virus (RSV) infection, hospitalisation, and death. This study aimed to gather data on RSV disease among older adults in NCHs and identify reported risk factors for RSV hospitalisation and case fatality. Methods The study protocol was registered in PROSPERO (CRD42022371908). We searched MEDLINE, EMBASE and Global Health databases to identify articles published between 2000 and 2023. Observational and experimental studies conducted among older adults in NCHs requiring assistive care and reporting RSV illness were included and relevant data were extracted. Results Of 18,690 studies screened, 32 were selected for full-text review and 20 were included. Overall, the number of NCH residents ranged from 42 to 1,459 with a mean age between 67.6 and 85 years. Attack rates ranged from 6.7 – 47.6% and annual incidence ranged from 0.5 – 14%. Case fatality rates ranged from 7.7 – 23.1%. We found similar annual incidence rates of RSV-positive acute respiratory infection (ARI) of 4,582 (95% CI: 3,259 – 6,264) and 4,785 (95% CI: 2,258 – 10,141) per 100,000 reported in two studies. Annual incidence rate of RSV-positive lower respiratory tract infection was 3,040 (95% CI: 1,986 – 4,454) cases per 100,000 adults. Annual RSV-ARI hospital admission rates were between 600 (95% CI: 190 -10,000) and 1,104 (95% CI: 350 – 1,930) per 100,000 person-years. Among all RSV disease cases, commonly reported chronic medical conditions included chronic obstructive pulmonary disease (COPD), heart failure, ischemic heart disease, coronary artery disease, hypertension, diabetes, kidney dysfunction, cerebrovascular accident, malignancies, dementia, and those with a Charlson comorbidity score > 6.5. Conclusion Data on RSV infection among NCH residents are limited and largely heterogeneous but document a high risk of illness, frequent hospitalisation, and high mortality. Preventive interventions, such as vaccination should be considered for this high-risk population. Nationally representative epidemiologic studies and NCH-based viral pathogen surveillance could more precisely assess the burden on NCH residents.

Adenovirus, a common respiratory pathogen, has witnessed a notable rise in incidence rates across various regions in Pakistan. Utilizing epidemiological data and climate records, this research discerns a potential linkage between the burgeoning adenovirus cases and alterations in regional climate patterns. Through statistical analysis and modeling techniques, the study aims to elucidate the relationship between climatic variables such as temperature, humidity, and precipitation, and the prevalence of adenovirus infections. Understanding these dynamics is crucial for developing effective public health interventions and preparedness strategies to mitigate the impact of adenovirus outbreaks in Pakistan. Furthermore, this research contributes to the broader discourse on the intersection of infectious diseases and climate change, highlighting the need for comprehensive adaptive measures to address emerging health challenges in a changing environment.

Background: During the 2022-23 season, three autonomous communities recommended influenza vaccination for all children between 6 and 59 months. The objective is to evaluate the adverse effects associated with the administered influenza vaccines in the Region of Murcia, as well as their influence on the recommendation of the same to acquaintances or repetition in future seasons. Material and methods: Cross-sectional descriptive study with an online questionnaire sent to the parents of vaccinated minors of 6-23 months of age receiving inactivated intramuscular vaccine (IIV) or 24-59 months of age receiving live-attenuated intranasal vaccine (LAIV). Results: among 4,971 surveys received the most common adverse effect for LAIV and IIV were runny nose (40.90%) and local pain (31.94%) respectively. Sixty percent of adverse effects lasted ≤1 day, and around 10% lasted ≥3 days. The interference of adverse effects with the minor’s daily life was very infrequent (3.32%), as was the need for visiting the medical office (2.68%). Overall, 96.44% of parents would recommend influenza vaccination to friends and relatives after the experience. Only 3.56% would not recommend it, while 1.68% would not vaccinate their child against influenza again. The most frequently cited reason being adverse effects. Conclusions: Our study shows the safety of influenza vaccines. Despite the low impact of adverse effects, they influence some parents in their intention to continue vaccinating or recommending it to acquaintances, which remarks the need to reinforce the information given to parents so that this fact does not influence.

Background: Household transmission of SARS-CoV-2 is a driver of the ongoing COVID-19 pandemic. Understanding factors that contribute to secondary infection rates (SIR) can define changing trends and inform public health policies. Methods: The ORegon CHild Absenteeism due to Respiratory Disease Study (ORCHARDS) prospectively monitors respiratory viruses within the Oregon School District (OSD) in southcentral Wisconsin. Households with students who had ≥2 respiratory symptoms were eligible and opted to participate in ORCHARDS. Between October 28, 2020, and May 16, 2022, all household members provided self-collected nasal specimens on days 0, 7, and 14 for SARS-CoV-2 detection using real-time reverse-transcription-polymerase chain reaction. We used logistic regression to investigate individual- and household-level characteristics associated with SARS-CoV-2 transmission. Results: Overall, 127 households comprising 572 individuals (48% female; 52% male; 0.4% non-binary; 77% >18 years) had at least one detection of SARS-CoV-2. The overall SIR was 47% and decreased over time (pre-Delta=72% [95%CI: 58%-83%]; Delta=51% [40%-63%]; and Omicron=41% [36%-47%]. Odds of household transmission were 63% lower during the Omicron period compared to the pre-Delta period (OR=0.36 [95%CI: 0.13-0.94] P=0.037). Greater household density (members/bedroom) was significantly associated with household transmission during the Omicron period (OR=6.8, [2.19-21.37] P=0.001). Index case age, illness severity, and individual symptoms were not significantly associated with odds of household transmission. Conclusions: Greater household density was associated with higher risk of SARS-CoV-2 transmission, but the risk declined over time with subsequent variants. Interplay between variants, prior infection, and individual/household factors may identify modifiable factors (e.g., behavior, vaccination) to reduce future transmission risk.

not-yet-known not-yet-known not-yet-known unknown We estimated XBB.1.5 vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection among adults aged ≥65 years during the 2023/24 JN.1 lineage-predominant period in a European multi-country test-negative case-control study at primary care level. We estimated VE adjusted by study site, age, sex, chronic conditions and onset date. We included 220 cases and 1733 controls. The VE was 48% (95% CI: 12–71), 23% (95% CI: -11–48) and 5% (95% CI: -92–56) among those with symptom onset 1–5 , 6–11, and ≥12 weeks after vaccination, respectively. XBB.1.5 vaccine provided short and moderate protection against JN.1 symptomatic infection.

Influenza virus infection may lead to fatal complications including multi-organ failure and sepsis. The influenza virus was detected in various extra-pulmonary organs in autopsy studies during the 2009 pandemic. However, limited research has been conducted on the presence of viral particle or viral components in the peripheral blood. We established a mouse model for severe H1N1 influenza. The bile and blood samples were collected over time and inoculated into embryonated chicken eggs. We detected live influenza virus with plaque assay test and negative stain with electronic microscopy in bile and blood samples in early infection. Immunofluorescence showed influenza viral components in the liver tissue. No live virus was isolated in the bile in mice intragastrically administered with influenza virus, indicating that the virus was spread from the blood stream. Targeted metabolomics analysis of bile acid and liver tissues showed that a secondary bile acid (3-dehydrocholic acid) was decreased after influenza H1N1 infection. Genes related with fatty acid metabolism and bile secretion pathways were down-regulated in liver after influenza virus infection. Our study indicated that influenza virus viremia is present in severe influenza, and that the liver is a target organ for influenza viral sepsis.

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