Marco Del Riccio, Jojanneke van Summeren, Saverio Caini, Koos van der Velden, Aura Timen
We studied worldwide influenza surveillance data (2022–2024), particularly in 145 countries and 260 country-seasons: influenza A represented 77.2% of identified cases, rising from 72.5% prepandemic, with A-dominated seasons increasing from 84.6% to 92.3%. During the same period, B/Yamagata was not detected and uncharacterized B cases dropped from 21.0% to 7.5%, possibly reflecting improved surveillance efforts. These results highlight postpandemic changes in influenza circulation and have important implications for vaccine composition, virus monitoring, and global prevention strategies.
{"title":"How Has the Disappearance of Influenza B/Yamagata Altered the Proportion of Influenza A and B Cases? Early Findings From Post-COVID Pandemic Global Surveillance Data","authors":"Marco Del Riccio, Jojanneke van Summeren, Saverio Caini, Koos van der Velden, Aura Timen","doi":"10.1111/irv.70138","DOIUrl":"https://doi.org/10.1111/irv.70138","url":null,"abstract":"<p>We studied worldwide influenza surveillance data (2022–2024), particularly in 145 countries and 260 country-seasons: influenza A represented 77.2% of identified cases, rising from 72.5% prepandemic, with A-dominated seasons increasing from 84.6% to 92.3%. During the same period, B/Yamagata was not detected and uncharacterized B cases dropped from 21.0% to 7.5%, possibly reflecting improved surveillance efforts. These results highlight postpandemic changes in influenza circulation and have important implications for vaccine composition, virus monitoring, and global prevention strategies.</p>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 7","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70138","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144573870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Louis Gold, Kathleen M. McPhaul, Huang Lin, Ryan Doughty, Irina Maljkovic Berry, Filbert Hong, Jianyu Lai, Todd J. Treangen, Jelena Srebric, Donald K. Milton
Background
The SARS-CoV-2 pandemic focused attention on airborne-inhalation transmission and building ventilation. However, investment in solutions lags because few epidemiologic studies demonstrate a causal effect of ventilation on acute respiratory infection (ARI) transmission. This highlights a need for improved study designs to support causal inference.
Methods
To investigate the potential for causal inference, we analyzed prospective cohorts residing in a high-ventilation (HVent, ≥ 5 L/s per person) or a neighboring low-ventilation (LVent, < 5 L/s per person) college residence hall during two spring semesters (2018 and 2019). Swab samples, analyzed using a PCR panel for respiratory pathogens, were collected based on self-reported symptoms and contacts. Our analysis focused on roommate pairs where both had been tested within a 2-week period. Roommate pairs with concordant positive PCR results were categorized as possible transmission events. We used genetic sequencing and phylogenetic analysis to identify probable transmission clusters and events.
Results
We analyzed data from 368 cohort participants (82 HVent and 286 LVent), including 60 person-infections, with a trend toward 54% lower ARI risk among students living in HVent versus LVent residence halls. We identified 97 roommate pairs, 64 two-week intervals where both members were tested, 36 (2 HVent and 34 LVent) intervals with ≥ 1 infection, and four possible transmission events (all LVent). Sequence data available for two of the four events confirmed one probable transmission cluster and one probable transmission event.
Conclusions
Future college dorm transmission studies should prioritize enrolling roommates rather than individuals, measuring ventilation, and confirming transmission events through whole genome sequencing.
{"title":"Impact of Ventilation on Respiratory Virus Transmission in College Residence Hall Cohorts: Potential for Causal Inference About Mode of Transmission","authors":"T. Louis Gold, Kathleen M. McPhaul, Huang Lin, Ryan Doughty, Irina Maljkovic Berry, Filbert Hong, Jianyu Lai, Todd J. Treangen, Jelena Srebric, Donald K. Milton","doi":"10.1111/irv.70133","DOIUrl":"https://doi.org/10.1111/irv.70133","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The SARS-CoV-2 pandemic focused attention on airborne-inhalation transmission and building ventilation. However, investment in solutions lags because few epidemiologic studies demonstrate a causal effect of ventilation on acute respiratory infection (ARI) transmission. This highlights a need for improved study designs to support causal inference.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To investigate the potential for causal inference, we analyzed prospective cohorts residing in a high-ventilation (HVent, ≥ 5 L/s per person) or a neighboring low-ventilation (LVent, < 5 L/s per person) college residence hall during two spring semesters (2018 and 2019). Swab samples, analyzed using a PCR panel for respiratory pathogens, were collected based on self-reported symptoms and contacts. Our analysis focused on roommate pairs where both had been tested within a 2-week period. Roommate pairs with concordant positive PCR results were categorized as possible transmission events. We used genetic sequencing and phylogenetic analysis to identify probable transmission clusters and events.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We analyzed data from 368 cohort participants (82 HVent and 286 LVent), including 60 person-infections, with a trend toward 54% lower ARI risk among students living in HVent versus LVent residence halls. We identified 97 roommate pairs, 64 two-week intervals where both members were tested, 36 (2 HVent and 34 LVent) intervals with ≥ 1 infection, and four possible transmission events (all LVent). Sequence data available for two of the four events confirmed one probable transmission cluster and one probable transmission event.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Future college dorm transmission studies should prioritize enrolling roommates rather than individuals, measuring ventilation, and confirming transmission events through whole genome sequencing.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 7","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144537067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicole Wolter, Cheryl Cohen, Anne von Gottberg, Stefano Tempia, Jocelyn Moyes, Claire von Mollendorf, Florette K. Treurnicht, Orienka Hellferscee, Kathleen Subramoney, Malefu Moleleki, Cayla Reddy, Lorens Maake, Mvuyo Makhasi, Neydis Baute, Sibongile Walaza
Background
Understanding the contribution of pathogens to respiratory illness in infants is important to guide interventions. We assessed the aetiology of respiratory pathogens among infants hospitalised with respiratory and non-respiratory illness.
Methods
We conducted an unmatched case–control study among infants aged < 1 year. Cases were admitted with acute respiratory and non-respiratory illness in November 2016–October 2018. Controls were infants presenting for immunisation with no reported illness. Nasopharyngeal aspirates and blood were tested using multi-pathogen real-time PCR. Aetiological fraction (AF) was calculated using logistic regression, adjusting for HIV, age, season and pathogens with higher prevalence in cases than controls. Factors associated with respiratory illness hospitalisation were assessed using logistic regression.
Results
Overall, 1214 cases (846 respiratory, 368 non-respiratory) and 684 controls were included. Respiratory syncytial virus (RSV) (AF 94.0%), influenza (AF 72.6%) and human metapneumovirus (HMPV) (AF 74.9%) were significantly attributable to respiratory illness hospitalisation. Klebsiella pneumoniae had significant AF in both respiratory (AF 48.0%) and non-respiratory (AF 60.7%) hospitalisation. HIV exposure (adjusted odds ratio [aOR] 1.5, 95% confidence interval [CI] 1.1–2.0) and living with HIV (aOR 6.6, 95%CI 2.1–20.5), underlying illness (aOR 4.8, 95%CI 1.3–17.6), malnutrition (aOR 6.0, 95%CI 4.0–8.9), infection with RSV (aOR 19.7, 95%CI 11.4–34.1), influenza (aOR 5.7, 95%CI 2.3–14.1) or HMPV (aOR 4.1, 95%CI 2.0–8.6) were associated with respiratory illness hospitalisation.
Conclusions
Maternal immunisation to prevent severe RSV and influenza illness in infants should be prioritised. In addition, improved infant nutrition and the prevention of HIV-infection and HIV-exposure could reduce the high burden of severe respiratory illness.
{"title":"Aetiological Fraction of Influenza, Respiratory Syncytial Virus and Other Respiratory Pathogens in Infants Aged < 1 Year Hospitalised With Respiratory and Non-Respiratory Medical Illness in South Africa, 2016–2018","authors":"Nicole Wolter, Cheryl Cohen, Anne von Gottberg, Stefano Tempia, Jocelyn Moyes, Claire von Mollendorf, Florette K. Treurnicht, Orienka Hellferscee, Kathleen Subramoney, Malefu Moleleki, Cayla Reddy, Lorens Maake, Mvuyo Makhasi, Neydis Baute, Sibongile Walaza","doi":"10.1111/irv.70135","DOIUrl":"https://doi.org/10.1111/irv.70135","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Understanding the contribution of pathogens to respiratory illness in infants is important to guide interventions. We assessed the aetiology of respiratory pathogens among infants hospitalised with respiratory and non-respiratory illness.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We conducted an unmatched case–control study among infants aged < 1 year. Cases were admitted with acute respiratory and non-respiratory illness in November 2016–October 2018. Controls were infants presenting for immunisation with no reported illness. Nasopharyngeal aspirates and blood were tested using multi-pathogen real-time PCR. Aetiological fraction (AF) was calculated using logistic regression, adjusting for HIV, age, season and pathogens with higher prevalence in cases than controls. Factors associated with respiratory illness hospitalisation were assessed using logistic regression.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Overall, 1214 cases (846 respiratory, 368 non-respiratory) and 684 controls were included. Respiratory syncytial virus (RSV) (AF 94.0%), influenza (AF 72.6%) and human metapneumovirus (HMPV) (AF 74.9%) were significantly attributable to respiratory illness hospitalisation. <i>Klebsiella pneumoniae</i> had significant AF in both respiratory (AF 48.0%) and non-respiratory (AF 60.7%) hospitalisation. HIV exposure (adjusted odds ratio [aOR] 1.5, 95% confidence interval [CI] 1.1–2.0) and living with HIV (aOR 6.6, 95%CI 2.1–20.5), underlying illness (aOR 4.8, 95%CI 1.3–17.6), malnutrition (aOR 6.0, 95%CI 4.0–8.9), infection with RSV (aOR 19.7, 95%CI 11.4–34.1), influenza (aOR 5.7, 95%CI 2.3–14.1) or HMPV (aOR 4.1, 95%CI 2.0–8.6) were associated with respiratory illness hospitalisation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Maternal immunisation to prevent severe RSV and influenza illness in infants should be prioritised. In addition, improved infant nutrition and the prevention of HIV-infection and HIV-exposure could reduce the high burden of severe respiratory illness.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 7","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70135","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144519994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Ekin Azbazdar, Mert Dikmenogullari, Zeynep Kavalci, Zeynep A. Koçer
Background
Seasonal influenza A viruses (IAVs) remain a major global health concern, causing up to 650,000 deaths annually. Over the past century, four influenza pandemics have occurred, with H3N2 and H1N1 subtypes becoming endemic in humans. The hemagglutinin (HA) glycoprotein, essential for viral entry and a key vaccine target, contains critical antigenic sites. While antigenic drift enables immune evasion, certain substitutions can affect protein stability and intraprotein interactions, influencing viral fitness.
Methods
This study employed a Bayesian approach to investigate the phylogenetic origins of full-length HA genes from seasonal IAVs circulating in Izmir, Türkiye (2017–2023). Publicly available HA sequences from Türkiye were incorporated to assess selection pressures using four models available on Datamonkey and to examine antigenic mismatches between circulating viruses and vaccine strains. The structural impact of positively selected substitution was analyzed via molecular dynamics simulations.
Results
Phylogenetic analysis identified four and six subclades for H1N1 and H3N2, respectively, revealing cocirculation of genetically distinct strains within the same season. Both subtypes were under negative selection, but the N260D substitution in H1N1 was consistently detected under positive selection across all models. Molecular dynamics simulations suggested that this substitution may influence intraprotein dynamics with the vestigial esterase domain, introducing a transient electrostatic bond. Furthermore, H3N2 exhibited more antigenic mismatches than H1N1, including a novel mismatch in 2022–2023.
Conclusions
This is the first comprehensive study documenting the genetic evolution of IAVs in Türkiye over 6 years. Regional surveillance of antigenic changes can improve vaccine strain selection and vaccination strategies.
{"title":"Genetic Evolution of the Hemagglutinin Genes of Seasonal Influenza A Viruses in Türkiye Between 2017 and 2023","authors":"M. Ekin Azbazdar, Mert Dikmenogullari, Zeynep Kavalci, Zeynep A. Koçer","doi":"10.1111/irv.70134","DOIUrl":"https://doi.org/10.1111/irv.70134","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Seasonal influenza A viruses (IAVs) remain a major global health concern, causing up to 650,000 deaths annually. Over the past century, four influenza pandemics have occurred, with H3N2 and H1N1 subtypes becoming endemic in humans. The hemagglutinin (HA) glycoprotein, essential for viral entry and a key vaccine target, contains critical antigenic sites. While antigenic drift enables immune evasion, certain substitutions can affect protein stability and intraprotein interactions, influencing viral fitness.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study employed a Bayesian approach to investigate the phylogenetic origins of full-length HA genes from seasonal IAVs circulating in Izmir, Türkiye (2017–2023). Publicly available HA sequences from Türkiye were incorporated to assess selection pressures using four models available on Datamonkey and to examine antigenic mismatches between circulating viruses and vaccine strains. The structural impact of positively selected substitution was analyzed via molecular dynamics simulations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Phylogenetic analysis identified four and six subclades for H1N1 and H3N2, respectively, revealing cocirculation of genetically distinct strains within the same season. Both subtypes were under negative selection, but the N260D substitution in H1N1 was consistently detected under positive selection across all models. Molecular dynamics simulations suggested that this substitution may influence intraprotein dynamics with the vestigial esterase domain, introducing a transient electrostatic bond. Furthermore, H3N2 exhibited more antigenic mismatches than H1N1, including a novel mismatch in 2022–2023.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This is the first comprehensive study documenting the genetic evolution of IAVs in Türkiye over 6 years. Regional surveillance of antigenic changes can improve vaccine strain selection and vaccination strategies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 7","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70134","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144492621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wang Chun Kwok, Isaac Sze Him Leung, James Chung Man Ho, Chung Ki Tsui, David Chi Leung Lam, Mary Sau Man Ip, Kelvin Kai Wang To, Desmond Yat Hin Yap
Introduction
Respiratory syncytial virus (RSV) and influenza virus are important respiratory viruses. Although RSV vaccines have been developed and recommended for patients aged ≥ 60, there is limited data on the clinical impact among the non-elderly population. It is also important to know the patient subgroups that are at risk of complications from RSV infections.
Methods
We conducted a territory-wide retrospective study on adults hospitalized for RSV or influenza virus infection between 1/1/2016 and 6/30/2023 in Hong Kong. The in-patient mortality, severe respiratory failure (SRF), secondary bacterial pneumonia, and acute kidney injury (AKI) were compared. Subgroup analyses were performed in different age groups. The risk factors for mortality and serious respiratory outcomes were assessed.
Results
A total of 41,206 and 3565 patients were hospitalized for influenza and RSV infections. Patients with RSV infection showed a significantly higher risk of in-patient mortality, SRF, secondary bacterial pneumonia, and AKI compared with those with influenza (p < 0.001, for all), and the results were consistent for patients aged ≥ 60, < 60, and 50–59. End-stage kidney disease requiring real replacement therapy was an independent risk factor for in-patient mortality and serious respiratory outcomes in RSV infection across different age groups (p < 0.001, for all).
Conclusions
Adults hospitalized for RSV infection were associated with a significantly increased risk of in-patient mortality and adverse respiratory and kidney outcomes than those with influenza. The findings are consistent across various age groups, and the results call for an update on RSV vaccination recommendations in adults, especially for vulnerable subgroups.
{"title":"In-Hospital Mortality and Severe Respiratory and Renal Outcomes—A Territory-Wide Comparison Between RSV and Influenza","authors":"Wang Chun Kwok, Isaac Sze Him Leung, James Chung Man Ho, Chung Ki Tsui, David Chi Leung Lam, Mary Sau Man Ip, Kelvin Kai Wang To, Desmond Yat Hin Yap","doi":"10.1111/irv.70130","DOIUrl":"https://doi.org/10.1111/irv.70130","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Respiratory syncytial virus (RSV) and influenza virus are important respiratory viruses. Although RSV vaccines have been developed and recommended for patients aged ≥ 60, there is limited data on the clinical impact among the non-elderly population. It is also important to know the patient subgroups that are at risk of complications from RSV infections.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We conducted a territory-wide retrospective study on adults hospitalized for RSV or influenza virus infection between 1/1/2016 and 6/30/2023 in Hong Kong. The in-patient mortality, severe respiratory failure (SRF), secondary bacterial pneumonia, and acute kidney injury (AKI) were compared. Subgroup analyses were performed in different age groups. The risk factors for mortality and serious respiratory outcomes were assessed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A total of 41,206 and 3565 patients were hospitalized for influenza and RSV infections. Patients with RSV infection showed a significantly higher risk of in-patient mortality, SRF, secondary bacterial pneumonia, and AKI compared with those with influenza (<i>p</i> < 0.001, for all), and the results were consistent for patients aged ≥ 60, < 60, and 50–59. End-stage kidney disease requiring real replacement therapy was an independent risk factor for in-patient mortality and serious respiratory outcomes in RSV infection across different age groups (<i>p</i> < 0.001, for all).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Adults hospitalized for RSV infection were associated with a significantly increased risk of in-patient mortality and adverse respiratory and kidney outcomes than those with influenza. The findings are consistent across various age groups, and the results call for an update on RSV vaccination recommendations in adults, especially for vulnerable subgroups.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Erin Rachel Whitehouse, Paul Elish, Elona Kureta, Dragan Kochinski, Dragana Plavsa, Giorgi Chakhunashvili, Besfort Kryeziu, Sayragul Abdyldaeva, Miguel Angel Sanchez Ruiz, Sandra Cohuet, James Humphreys, Kujtim Mersini, Oksana Artemchuk, Maja Stosic, Olgha Tarkhan-Mouravi, Ariana Kalaveshi, Dinagul Otorbaeva, Kristina Stavridis, Silvia Bino, Marc-alain Widdowson, Eva Leidman, Iris Finci, Mark A. Katz
Background
Updated regional data on COVID-19 epidemiology and vaccination can inform vaccine policies and implementation strategies.
Methods
We used surveillance data on patients hospitalized from the European SARI Vaccine Effectiveness (EuroSAVE) network to describe COVID-19 epidemiology and COVID-19 vaccine uptake among adults hospitalized with severe acute respiratory infection (SARI) in six middle-income countries and areas (CAs) in the WHO European region during 2022–2024. For SARI patients, we collected data on demographics, comorbidities, vaccination status, and hospital course, and a respiratory specimen, which was tested for SARS-CoV-2 by RT-PCR. In October 2024, we surveyed national public health institute staff on national COVID-19 vaccine guidelines and availability.
Results
Of SARI patients, 833/3982 (20.9%) and 367/3752 (9.8%) tested positive for SARS-CoV-2 during May 2022–April 2023 and May 2023–April 2024, respectively. Of COVID-19 patients, 857 (71.4%) were ≥60 years old and 713 (59.4%) had ≥1 comorbidity. A higher proportion of COVID-19 patients required mechanical ventilation (30 [8.2%] vs. 23 [2.8%], p <0.001) and intensive care (70 [8.4%] vs. 48 [13.1%], p =0.016) during May 2023–April 2024 compared to May 2022–April 2023. COVID-19 vaccination in the last 12 months decreased from 25% in 2022–2023 to 3% in 2023–2024. Most CAs had not updated their COVID-19 vaccination guidelines to recommend annual vaccination, and only two had vaccines available.
Conclusions
Although COVID-19 was associated with severe disease among SARI patients, COVID-19 vaccination uptake was low among priority populations recommended for vaccination by WHO guidance. Continued efforts to understand reasons for low vaccine uptake and improve vaccine access will help protect those at greatest risk for COVID-19-associated morbidity and mortality.
{"title":"COVID-19 Hospitalizations, Vaccine Uptake, Vaccination Guidelines, and Vaccine Availability in Six Middle-Income Countries and Areas in Europe, May 2022–April 2024","authors":"Erin Rachel Whitehouse, Paul Elish, Elona Kureta, Dragan Kochinski, Dragana Plavsa, Giorgi Chakhunashvili, Besfort Kryeziu, Sayragul Abdyldaeva, Miguel Angel Sanchez Ruiz, Sandra Cohuet, James Humphreys, Kujtim Mersini, Oksana Artemchuk, Maja Stosic, Olgha Tarkhan-Mouravi, Ariana Kalaveshi, Dinagul Otorbaeva, Kristina Stavridis, Silvia Bino, Marc-alain Widdowson, Eva Leidman, Iris Finci, Mark A. Katz","doi":"10.1111/irv.70126","DOIUrl":"https://doi.org/10.1111/irv.70126","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Updated regional data on COVID-19 epidemiology and vaccination can inform vaccine policies and implementation strategies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used surveillance data on patients hospitalized from the European SARI Vaccine Effectiveness (EuroSAVE) network to describe COVID-19 epidemiology and COVID-19 vaccine uptake among adults hospitalized with severe acute respiratory infection (SARI) in six middle-income countries and areas (CAs) in the WHO European region during 2022–2024. For SARI patients, we collected data on demographics, comorbidities, vaccination status, and hospital course, and a respiratory specimen, which was tested for SARS-CoV-2 by RT-PCR. In October 2024, we surveyed national public health institute staff on national COVID-19 vaccine guidelines and availability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Of SARI patients, 833/3982 (20.9%) and 367/3752 (9.8%) tested positive for SARS-CoV-2 during May 2022–April 2023 and May 2023–April 2024, respectively. Of COVID-19 patients, 857 (71.4%) were ≥60 years old and 713 (59.4%) had ≥1 comorbidity. A higher proportion of COVID-19 patients required mechanical ventilation (30 [8.2%] vs. 23 [2.8%], p <0.001) and intensive care (70 [8.4%] vs. 48 [13.1%], p =0.016) during May 2023–April 2024 compared to May 2022–April 2023. COVID-19 vaccination in the last 12 months decreased from 25% in 2022–2023 to 3% in 2023–2024. Most CAs had not updated their COVID-19 vaccination guidelines to recommend annual vaccination, and only two had vaccines available.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Although COVID-19 was associated with severe disease among SARI patients, COVID-19 vaccination uptake was low among priority populations recommended for vaccination by WHO guidance. Continued efforts to understand reasons for low vaccine uptake and improve vaccine access will help protect those at greatest risk for COVID-19-associated morbidity and mortality.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144314935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ulrike Baum, Niina Ikonen, Oskari Luomala, Eero Poukka, Tuija Leino, Hanna Nohynek
Background
The Finnish influenza surveillance system combines traditional virological surveillance and analyses of electronic health records. This paper describes the influenza epidemiology in Finland (population: 5.5 million) during and after the COVID-19 pandemic based on national surveillance data from 2019 to 2024.
Methods
Influenza incidence was evaluated based on three register-based outcomes: laboratory-confirmed infections, primary health care visits, and hospitalizations. Virus-type distributions were analyzed from respiratory specimens. In register-based analyses, vaccination coverage and vaccine effectiveness were assessed for the two cohorts universally included in the Finnish vaccination program: children aged ≤ 6 years and adults aged ≥ 65 years.
Results
The 2019/2020 influenza epidemic ended with the introduction of COVID-19 containment measures. In 2020/2021, influenza was largely absent. The 2021/2022 epidemic peaked exceptionally late. Influenza activity returned to prepandemic levels in 2022/2023. None of the 717 sentinel specimens tested positive for B/Yamagata. Although the percentage of vaccinated young children was constant (31% [100,387/323,614] to 37% [126,984/346,344]), the percentage of vaccinated elderly people increased from 48% (577,404/1,211,732) in 2019/2020 to 63% (787,771/1,255,644) in 2021/2022. The vaccine effectiveness against hospitalization due to laboratory-confirmed influenza in young children and elderly people was 68% (95% confidence interval: 38%; 83%) and 42% (34%; 50%) in 2022/2023, respectively, and slightly lower in 2023/2024.
Conclusions
The COVID-19 pandemic had two potentially lasting effects on influenza: elimination of the B/Yamagata lineage and improved vaccination coverage in the elderly population in Finland. To strengthen the Finnish influenza surveillance system, participation in sentinel surveillance must be improved.
{"title":"Influenza Epidemiology in Finland During and After the COVID-19 Pandemic: Surveillance Data Analysis (2019–2024)","authors":"Ulrike Baum, Niina Ikonen, Oskari Luomala, Eero Poukka, Tuija Leino, Hanna Nohynek","doi":"10.1111/irv.70131","DOIUrl":"https://doi.org/10.1111/irv.70131","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The Finnish influenza surveillance system combines traditional virological surveillance and analyses of electronic health records. This paper describes the influenza epidemiology in Finland (population: 5.5 million) during and after the COVID-19 pandemic based on national surveillance data from 2019 to 2024.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Influenza incidence was evaluated based on three register-based outcomes: laboratory-confirmed infections, primary health care visits, and hospitalizations. Virus-type distributions were analyzed from respiratory specimens. In register-based analyses, vaccination coverage and vaccine effectiveness were assessed for the two cohorts universally included in the Finnish vaccination program: children aged ≤ 6 years and adults aged ≥ 65 years.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The 2019/2020 influenza epidemic ended with the introduction of COVID-19 containment measures. In 2020/2021, influenza was largely absent. The 2021/2022 epidemic peaked exceptionally late. Influenza activity returned to prepandemic levels in 2022/2023. None of the 717 sentinel specimens tested positive for B/Yamagata. Although the percentage of vaccinated young children was constant (31% [100,387/323,614] to 37% [126,984/346,344]), the percentage of vaccinated elderly people increased from 48% (577,404/1,211,732) in 2019/2020 to 63% (787,771/1,255,644) in 2021/2022. The vaccine effectiveness against hospitalization due to laboratory-confirmed influenza in young children and elderly people was 68% (95% confidence interval: 38%; 83%) and 42% (34%; 50%) in 2022/2023, respectively, and slightly lower in 2023/2024.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The COVID-19 pandemic had two potentially lasting effects on influenza: elimination of the B/Yamagata lineage and improved vaccination coverage in the elderly population in Finland. To strengthen the Finnish influenza surveillance system, participation in sentinel surveillance must be improved.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144309094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jianyu Lai, P. Jacob Bueno de Mesquita, Filbert Hong, Tianzhou Ma, Benjamin J. Cowling, Donald K. Milton
Background
Nasally inoculated influenza cases reported milder symptoms and shed lower viral RNA load in exhaled breath aerosols (EBA) than people with classic influenza-like illness in a previous study. Whether nasally inoculated influenza is representative of mild natural influenza infection is unknown. We extend previous analyses to include a broader range of community-acquired cases.
Methods
We previously studied (A) volunteers intranasally inoculated with a dose of 5.5 log10TCID50 of influenza A/Wisconsin/67/2005 (H3N2) and (B) cases with classic influenza-like illness including fever recruited in 2013. We now add (C) cases from a 2017–2019 surveillance cohort of college dormitory residents and their contacts and (D) cases from a university health center in 2019. All cases had an influenza A(H3) infection. We collected 30-min EBA samples using a Gesundheit-II sampler.
Results
Community-acquired cases from the surveillance cohort (C) shed more EBA viral RNA and were more symptomatic than the inoculated cases (A) but shed less viral RNA than the symptom-selected natural cases (B) from 2013, but not (D) from 2019. Despite similar symptoms to the 2013 selected cases (B), the 2019 community-acquired cases (D) recruited post-infection had lower fine aerosol viral RNA.
Conclusions
Nasal inoculation of influenza virus did not reproduce EBA viral RNA shedding or symptoms observed in mild natural infection. Circulating strains of influenza A(H3) may differ year-to-year in the extent to which symptomatic cases shed virus into fine aerosols. New models, including possibly aerosol inoculation, are needed to study viral aerosol shedding from the human respiratory tract.
{"title":"Comparison of Viral Aerosol Shedding by Mild and Moderately Symptomatic Community-Acquired and Nasally Inoculated Influenza A(H3) Infection","authors":"Jianyu Lai, P. Jacob Bueno de Mesquita, Filbert Hong, Tianzhou Ma, Benjamin J. Cowling, Donald K. Milton","doi":"10.1111/irv.70129","DOIUrl":"https://doi.org/10.1111/irv.70129","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Nasally inoculated influenza cases reported milder symptoms and shed lower viral RNA load in exhaled breath aerosols (EBA) than people with classic influenza-like illness in a previous study. Whether nasally inoculated influenza is representative of mild natural influenza infection is unknown. We extend previous analyses to include a broader range of community-acquired cases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We previously studied (A) volunteers intranasally inoculated with a dose of 5.5 log<sub>10</sub>TCID<sub>50</sub> of influenza A/Wisconsin/67/2005 (H3N2) and (B) cases with classic influenza-like illness including fever recruited in 2013. We now add (C) cases from a 2017–2019 surveillance cohort of college dormitory residents and their contacts and (D) cases from a university health center in 2019. All cases had an influenza A(H3) infection. We collected 30-min EBA samples using a Gesundheit-II sampler.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Community-acquired cases from the surveillance cohort (C) shed more EBA viral RNA and were more symptomatic than the inoculated cases (A) but shed less viral RNA than the symptom-selected natural cases (B) from 2013, but not (D) from 2019. Despite similar symptoms to the 2013 selected cases (B), the 2019 community-acquired cases (D) recruited post-infection had lower fine aerosol viral RNA.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Nasal inoculation of influenza virus did not reproduce EBA viral RNA shedding or symptoms observed in mild natural infection. Circulating strains of influenza A(H3) may differ year-to-year in the extent to which symptomatic cases shed virus into fine aerosols. New models, including possibly aerosol inoculation, are needed to study viral aerosol shedding from the human respiratory tract.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christofferson, R., Giovanni, J., Koumans, E., Ategbole, M., Clark, S., Godfred-Cato, S., Menon, M., Sastalla, I., Schweitzer, B. and Uyeki, T. (2025), A Systematic Review of Prolonged SARS-CoV-2 Shedding in Immunocompromised Persons. Influenza and Other Respiratory Viruses, 19: e70121, https://doi.org/10.1111/irv.70121.
The affiliations for Beth K. Schweitzer and Timothy M. Uyeki were listed incorrectly. The correct affiliation for both authors is “Centers for Disease Control and Prevention, Atlanta, Georgia, USA.”
We apologize for this error.
Christofferson， R., Giovanni， J., Koumans， E., Ategbole， M., Clark， S., godfrey - cato， S., Menon， M., Sastalla， I., Schweitzer， B.和Uyeki， T.(2025)，免疫功能不全人群中SARS-CoV-2长期释放的系统评价。流感和其他呼吸道病毒，19:e70121, https://doi.org/10.1111/irv.70121。贝丝·k·施韦策和蒂莫西·m·乌耶基的所属单位都列错了。两位作者的正确联系是“Centers for Disease Control and Prevention, Atlanta, Georgia， USA”。我们为这个错误道歉。
{"title":"Correction to “A Systematic Review of Prolonged SARS-CoV-2 Shedding in Immunocompromised Persons”","authors":"","doi":"10.1111/irv.70127","DOIUrl":"https://doi.org/10.1111/irv.70127","url":null,"abstract":"<p>\u0000 <span>Christofferson, R.</span>, <span>Giovanni, J.</span>, <span>Koumans, E.</span>, <span>Ategbole, M.</span>, <span>Clark, S.</span>, <span>Godfred-Cato, S.</span>, <span>Menon, M.</span>, <span>Sastalla, I.</span>, <span>Schweitzer, B.</span> and <span>Uyeki, T.</span> (<span>2025</span>), <span>A Systematic Review of Prolonged SARS-CoV-2 Shedding in Immunocompromised Persons</span>. <i>Influenza and Other Respiratory Viruses</i>, <span>19</span>: e70121, https://doi.org/10.1111/irv.70121.\u0000 </p><p>The affiliations for Beth K. Schweitzer and Timothy M. Uyeki were listed incorrectly. The correct affiliation for both authors is “Centers for Disease Control and Prevention, Atlanta, Georgia, USA.”</p><p>We apologize for this error.</p>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70127","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tess Stopczynski, Justin Z. Amarin, James W. Antoon, Olla Hamdan, Laura S. Stewart, James Chappell, Andrew J. Spieker, Eileen J. Klein, Janet A. Englund, Geoffrey A. Weinberg, Peter G. Szilagyi, John V. Williams, Marian G. Michaels, Julie A. Boom, Leila C. Sahni, Mary Allen Staat, Elizabeth P. Schlaudecker, Jennifer E. Schuster, Rangaraj Selvarangan, Christopher J. Harrison, Heidi L. Moline, Ariana P. Toepfer, Angela P. Campbell, Samantha M. Olson, Natasha B. Halasa
Background
Influenza contributes to a high burden of pediatric emergency department (ED) visits annually. Guidelines recommend outpatient antiviral treatment for children at higher risk of severe influenza and recommend considering treatment for those who present within 2 days of symptom onset. We describe antiviral prescription in children with influenza presenting to the ED.
Methods
We analyzed data from the New Vaccine Surveillance Network (2016–2020), including children presenting to the ED and enrolled with confirmed influenza at one of seven pediatric academic centers. We compared characteristics of children prescribed antivirals to those who were not, using generalized estimating equations models to identify predictors of antiviral prescription. Children were considered at higher risk of severe influenza if they were < 5 years old or had an underlying condition.
Results
Overall, 2472 (15%) of 16,915 enrolled children tested positive for influenza virus. Among these, 1931 (78%) were at higher risk of severe influenza; only 622 (32%) received an antiviral. Among 233 (9%) children not at high risk with symptom onset ≤ 2 days, 62 (27%) were prescribed an antiviral. Children prescribed an antiviral had a shorter duration of illness prior to presenting to the ED. For children at higher risk of severe influenza, odds of antiviral prescription were higher for those clinically tested for influenza and with underlying conditions.
Conclusion
Clinical testing and having an underlying condition were associated with antiviral prescription in children at higher risk of severe influenza. However, only 1/3 of those at higher risk were prescribed an antiviral. Strategies to increase antiviral use for children at higher risk for influenza in the ED are needed.
{"title":"Antiviral Prescription in Children With Influenza in US Emergency Departments: New Vaccine Surveillance Network (NVSN), 2016–2020","authors":"Tess Stopczynski, Justin Z. Amarin, James W. Antoon, Olla Hamdan, Laura S. Stewart, James Chappell, Andrew J. Spieker, Eileen J. Klein, Janet A. Englund, Geoffrey A. Weinberg, Peter G. Szilagyi, John V. Williams, Marian G. Michaels, Julie A. Boom, Leila C. Sahni, Mary Allen Staat, Elizabeth P. Schlaudecker, Jennifer E. Schuster, Rangaraj Selvarangan, Christopher J. Harrison, Heidi L. Moline, Ariana P. Toepfer, Angela P. Campbell, Samantha M. Olson, Natasha B. Halasa","doi":"10.1111/irv.70124","DOIUrl":"https://doi.org/10.1111/irv.70124","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Influenza contributes to a high burden of pediatric emergency department (ED) visits annually. Guidelines recommend outpatient antiviral treatment for children at higher risk of severe influenza and recommend considering treatment for those who present within 2 days of symptom onset. We describe antiviral prescription in children with influenza presenting to the ED.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We analyzed data from the New Vaccine Surveillance Network (2016–2020), including children presenting to the ED and enrolled with confirmed influenza at one of seven pediatric academic centers. We compared characteristics of children prescribed antivirals to those who were not, using generalized estimating equations models to identify predictors of antiviral prescription. Children were considered at higher risk of severe influenza if they were < 5 years old or had an underlying condition.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Overall, 2472 (15%) of 16,915 enrolled children tested positive for influenza virus. Among these, 1931 (78%) were at higher risk of severe influenza; only 622 (32%) received an antiviral. Among 233 (9%) children not at high risk with symptom onset ≤ 2 days, 62 (27%) were prescribed an antiviral. Children prescribed an antiviral had a shorter duration of illness prior to presenting to the ED. For children at higher risk of severe influenza, odds of antiviral prescription were higher for those clinically tested for influenza and with underlying conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Clinical testing and having an underlying condition were associated with antiviral prescription in children at higher risk of severe influenza. However, only 1/3 of those at higher risk were prescribed an antiviral. Strategies to increase antiviral use for children at higher risk for influenza in the ED are needed.</p>\u0000 </section>\u0000 </div>","PeriodicalId":13544,"journal":{"name":"Influenza and Other Respiratory Viruses","volume":"19 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/irv.70124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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