Influenza and Other Respiratory Viruses最新文献

Background: From 2016 to 2018, the World Health Organization (WHO) initiated a global RSV surveillance pilot program in 14 countries, expanding to 25 countries from 2019 to 2023. As part of this, a sequencing program was introduced to improve the understanding of RSV global genetic diversity prior to and following the introduction of interventions such as passive immunization, vaccines, and antivirals.

Methodology: All RSV sequence data submitted to GISAID by WHO project countries from January 1, 2019, to December 31, 2023, was analyzed to evaluate progress in sequencing, lineage distribution, and RSV fusion (F) protein diversity.

Results: From 2019 to 2023, 44,571 RSV sequences were submitted to GISAID, including 61% RSV-A and 39% RSV-B, with 34% being whole-genome sequences. WHO project countries contributed 13,280 sequences (30%), with submissions increasing from 158 in 2020 to 3716 in 2023. Median data submission time improved from 1116 days in 2020 to 206 days in 2023. The dominant lineage detected was A.D.1 (20%) for RSV-A and B.D.4.1.1 (29%) for RSV-B. The F protein sequences showed high amino acid conservation: 97% for RSV-A and 96% for RSV-B.

Conclusion: Substantial progress has been made in RSV genomic sequencing capacities in WHO project countries as seen by the increased submissions and improved timeliness of sequence data. RSV exhibited co-circulating lineages (RSV-A and RSV-B) with low F protein diversity. It is important to sustain and further strengthen RSV sequencing capacities in all WHO regions as part of the ongoing WHO Global Genomic Surveillance strategy.

Infection with respiratory syncytial virus (RSV) represents a substantial burden of disease, especially in children. While one vaccine (RSVpreF) has been recommended for administration in pregnant women, another one (RSVPreF3-Mat) has been discontinued in a Phase 3 study due to an increased incidence of preterm births in the study group. When comparing the studies related to these two vaccine candidates, the differences in preterm birth rates appear inconsistent. For a more differentiated evaluation of birth outcomes associated with maternal RSV vaccination, we recommend introducing the previously described concept of "small and vulnerable newborns."

The Canadian Sentinel Practitioner Surveillance Network used the test-negative design to assess KP.2 vaccine effectiveness (VE) against medically attended outpatient COVID-19 between November 2024 and April 2025 among participants ≥ 12 years. Analyses included 5410 controls (19% vaccinated) and 435 COVID-19 cases (10% vaccinated). Nearly three-quarters (72%) of contributing case viruses were genetically characterized, with XEC (35%) and KP.3.1.1 (38%) variants most commonly identified. Vaccination reduced COVID-19 risk by approximately half (54%; 95% CI: 36-68) relative to unvaccinated individuals. VE was greatest during the first 2 months postvaccination, reducing risk by two-thirds and declining to minimal protection by the fifth month postvaccination.

Background: In the 2024-2025 season, influenza activity returned to pre-COVID-19 pandemic levels, with A(H1N1)pdm09 as the predominant subtype. Reassessment vaccine effectiveness (VE) in hospitalized patients is critical to inform potential adjustments to vaccination policy.

Methods: Using a test-negative design, we evaluated the VE of the seasonal influenza vaccine during the 2024-2025 season against A(H1N1)pdm09-associated hospitalizations with severe acute respiratory infections (SARI) in Beijing, China, from December 9, 2024 to February 9, 2025. VE was estimated by comparing the odds of influenza vaccination between case-patients (those testing positive for A(H1N1)pdm09) and controls (influenza test-negative patients), applying inverse-propensity-to-be-vaccinated weights.

Results: The analysis included 1608 hospitalized SARI patients (17.4% tested positive for A(H1N1)pdm09; 13.8% were vaccinated overall). The adjusted VE against A(H1N1)pdm09-associated hospitalizations was 18.8% (95% CI: 0.9% to 33.6%) overall. Specifically, the VE was 45.4% (95% CI: 10.0% to 67.1%) in children aged 0.5-17 years, 43.8% (95% CI: -20.8% to 76.1%) in adults aged 18-59 years, and 8.6% (95% CI: -15.8% to 27.9%) in older adults ≥ 60 years. Among individuals with chronic conditions, the VE was 18.5% (95% CI: -2.3% to 35.2%) and was higher among those with chronic respiratory conditions (40.6%, 95% CI: -1.7% to 65.7%).

Conclusions: During the 2024-2025 season in Beijing, the overall VE against A(H1N1)pdm09-associated SARI hospitalizations was suboptimal. However, moderate VE was observed among children and younger adults, while limited effectiveness was seen in the elderly. Optimizing influenza vaccination strategies, including the introduction of high-dose or adjuvanted vaccines to enhance immune response in older adults, is crucial to alleviate influenza-associated hospitalizations.

Background: The continuing circulation and evolution of seasonal influenza viruses remains a public health and socioeconomic threat on a global scale. Viral surveillance and vaccination of the public have been relied upon to confer and boost immunity in the population. Traditionally, influenza strains are propagated in embryonated chicken eggs, but this process remains imperfect and subject to genetic drift of the virus and a reliable source of eggs. Cell culture-based propagation of influenza virus has recently been commercialized, but this method has been difficult to adapt to lab settings.

Methods: Madin-Darby canine kidney (MDCK) cells were adapted to thrive in serum-free growth in suspension. The suspension MDCK (sMDCK) line was characterized by measuring replication and viability during routine passage and infection. Fifteen different influenza strains were propagated using this model and were assayed to determine hemagglutination and plaque forming units and compared to influenza strains grown in adherent cell culture. Microneutralization tests were also conducted to ensure each strain maintained the proper antigenicity.

Results: The cell line was successfully adapted to serum-free growth in suspension. For each virus strain, the sMDCK platform successfully produced a virus stock in 1-3 days. Additionally, sMDCK progeny virus maintained its antigenicity based on neutralization assays.

Conclusions: This simple, scalable method was used to reliably propagate 15 influenza strains with the elimination of costly reagents and animal serum. The results are comparable to traditional methods, and the protocol presented in this work could be adapted to nearly any laboratory setting.

Background: Reassurance over the quality of self-collected swabs could provide additional evidence to support the self-collection of respiratory specimens as a valid and efficient method in large-scale cohort studies.

Methods: This study assessed the diagnostic performance of self-collected pooled nasal and throat swabs compared to staff-collected swabs for detecting SARS-CoV-2 and influenza virus by RT-PCR in a cohort of older adults (aged 69-87 years) from March to October 2024.

Results: Self-collected swabs demonstrated high sensitivity (95.2% for SARS-CoV-2, 100% for influenza A) and specificity (99.2% and 100%, respectively) against staff-collected swabs. Cycle threshold values showed no statistically significant differences and strong correlations between the two methods.

Conclusions: These findings suggest self-collected swabs are a reliable alternative for community-based respiratory viruses surveillance in older adults, supporting their use in large-scale studies.

The extent of cross-reactive antibodies to SARS-CoV-2 elicited by seasonal human coronaviruses (HCoVs) remains unclear. We analyzed longitudinal preinfection and postinfection IgG responses in 62 older adults with PCR-confirmed HCoV infections from sera collected prior to the emergence of SARS-CoV-2. At baseline, 12.9% and 16.1% had low-titer antibodies against SARS-CoV-2 spike (S) or nucleocapsid (N) proteins, respectively, but postinfection increases were marginal. Our findings suggest seasonal HCoV infections induce limited SARS-CoV-2 cross-reactive antibodies in community-dwelling older adults.

Background: Emergency department (ED) syndromic surveillance (EDSyS) often relies on preliminary or ED discharge diagnosis codes as indicators of influenza, but few studies provide a justification for their selection. This retrospective analytical study aimed to optimise the selection of diagnostic codes in EDSyS for monitoring influenza activity and severity.

Methods: Diagnostic codes potentially relating to a respiratory infection and assigned to people presenting to over 180 EDs in New South Wales (NSW), Australia, were grouped into 16 mutually exclusive 'ED Syndromes'. Time series of the proportion of ED presentations for each ED syndrome by epidemiological week between 2010 and 2019 were compared to a reference series of the percentage influenza positive results from sentinel laboratories, using two similarity and three timeliness statistics. Hospital inpatient admission and laboratory notification data linked to each ED presentation allowed assessment of patient infection status and outcomes.

Results: 'Unspecified Viral' (any non-specific viral illness, without reference to the respiratory system) and ED syndromes based on influenza like Illness (ILI) and influenza had the best combination of similarity and timeliness measures. Linked data identified relatively high rates of hospital admission, laboratory-confirmed influenza and inpatient influenza diagnosis for ED syndromes based on pneumonia and lower respiratory tract infection.

Conclusion: In addition to ILI and influenza, ED syndromes based on unspecified viral illnesses can be used for EDSyS to assess influenza timing and transmissibility in NSW, Australia. The approach outlined in our paper can identify diagnostic codes to improve severity assessment of seasonal influenza using EDSyS.

Background: Human adenoviruses (HAdV) circulate globally, but their seasonal patterns remain poorly defined. We aimed to characterize the timing, amplitude, and duration of HAdV epidemics worldwide and to compare patterns before and after the COVID-19 pandemic.

Methods: Virological surveillance data on HAdV were obtained from the WHO FluNet database: data from 65 countries were analyzed to estimate epidemic peak timing, amplitude, and duration across the Northern and Southern Hemispheres and the intertropical belt, comparing prepandemic (2016-2019) with postpandemic (2021-2024) periods. To ensure robustness, analyses were restricted to country-seasons with ≥ 30 reporting weeks.

Results: From 2016 to 2024, 65 countries reported roughly 148,000 HAdV detections across 335 country-seasons; 46% of seasons had ≥ 50 detections. In the 20 countries with sufficient data for seasonality analyses, median epidemic duration was 31 weeks (range 5-42) and median peak amplitude 70% (40%-98%). Peak timing followed latitude: June-July in Southern Hemisphere, November-December in high-latitude Northern countries, March-April in lower latitude. After COVID-19, several countries showed marked timing shifts, with concurrent changes in amplitude.

Conclusions: After the onset of the COVID-19 pandemic, the usual seasonal patterns of HAdV were altered, with pronounced shifts in peak timing across settings and latitudes. These results underscore the need for strong, ongoing, type-specific surveillance to guide public health strategies.

Background: Quantifying the burden of respiratory syncytial virus (RSV) in adults is challenging compared to influenza, and data among older adults remain scarce in Japan. Country-specific evidence is essential to support RSV vaccination policy.

Methods: This prospective, multicenter study (APSG-J2) targeted hospitalized adults with community-acquired pneumonia (CAP) and other acute respiratory infections (ARI) in seven community hospitals across four catchment areas in Japan between September 2022 and August 2024. Respiratory samples were analyzed using a multiplex polymerase chain reaction (PCR) kit to detect RSV and influenza. Incidence rates of RSV- and influenza-associated hospitalizations were estimated using study data and national statistics, stratified by age and region.

Results: Among 3047 hospitalized patients with CAP/ARI, 1499 (49.2%) underwent multiplex PCR testing. RSV and influenza were detected in 2.8% and 3.3% of tested patients, respectively. The incidences of RSV-associated CAP/ARI hospitalizations among adults aged ≥ 65 years were 29 and 36 per 100,000 person-years in the first and second years, respectively, with higher incidences among those aged ≥ 85 years (150 and 131 per 100,000 person-years). Influenza incidence increased markedly in the second year (from 11 to 71 per 100,000 person-years for adults age ≥ 65 years), possibly reflecting post-COVID-19 transmission changes.

Conclusions: In this multicenter study, we estimated the incidence of RSV- and influenza-associated hospitalizations among adults in Japan. The findings indicated that the incidence increased with age, and influenza-associated hospitalizations increased in the second year. Continued surveillance is essential to accurately assess RSV burden in the adult population.