The Journal of Infectious Diseases最新文献

{"title":"High Nasopharyngeal SARS-CoV-2 Load and Delayed Clearance in Hospitalized Patients With Blood Autoantibodies Neutralizing Type I Interferons.","authors":"Astrid Marchal,Thibault Kerdiles,Aglaé Perrin,Adrian Gervais,Paul Bastard,Lucy Bizien,Guillaume Lingas,Clément R Massonnaud,Maude Bouscambert-Duchamp,Alexandre Gaymard,Nathan Peiffer-Smadja,France Mentre,Jérémie Guedj,Laurent Abel,Jean-Laurent Casanova,Anne Puel,Maya Hites,Florence Ader,Julie Bertrand,Aurélie Cobat, ","doi":"10.1093/infdis/jiag172","DOIUrl":"https://doi.org/10.1093/infdis/jiag172","url":null,"abstract":"Autoantibodies neutralizing type I interferon (AAN-I-IFNs) underlie life-threatening COVID-19. In hospitalized COVID-19 patients of the DisCoVeRy trial (NCT-04315948), AAN-I-IFNs were associated with higher nasopharyngeal viral load at inclusion (P = 1.4 × 10-3) and delayed viral clearance (P = .013). Blood AAN-I-IFNs, high viral load and delayed clearance were also independent risk factors for critical COVID-19.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decreased persistence of maternal antibodies in infants who are HIV-exposed and uninfected.","authors":"Yiwei Jiang,Tessa Goetghebuer,Stefan Embacher,Anaïs Thiriard,Veronique Olislagers,Dansala Welba,Martin Taton,Ines Vu Duc,Katty Renard,Shilpee Sharma,Bérengère de Toeuf,Arnaud Marchant","doi":"10.1093/infdis/jiag236","DOIUrl":"https://doi.org/10.1093/infdis/jiag236","url":null,"abstract":"BACKGROUNDInfants who are HIV-exposed uninfected (iHEU) are more susceptible to severe infections in the first months of life compared with infants who are HIV-unexposed (iHU). Previous studies showed an association with reduced transplacental transfer of maternal antibodies. Whether maternal HIV infection also impacts the persistence of transferred maternal antibodies is unknown.METHODSSerum samples were collected from 58 mother-infant pairs at delivery (maternal and cord blood) and at 1 month of age. A multiplex assay was established to test the levels of IgG against tetanus, pertussis, cytomegalovirus (CMV), respiratory syncytial virus (RSV) and HIV.RESULTSCompared with iHU, iHEU had significantly lower antigen-specific antibody concentrations at 1 month across targeted pathogens, independent of maternal baselines and gestational ages. Both impaired placental transfer and persistence of maternal antibodies contributed to the lower antibody levels in iHEU. Timing of antiretroviral therapy (ART) initiation in mothers had profound impact on the dynamics of antibodies in iHEU. Compared with initiation of ART before pregnancy, iHEU whose mothers initiated ART during pregnancy had the lowest antibody concentrations at 1 month.CONCLUSIONSOur study shows that in addition to reduced placental transfer, maternal HIV infection is associated with reduced persistence of maternal antibodies after birth. This reduction could contribute to the increased susceptibility of iHEU to severe infections and further supports the need to offer vaccination during pregnancy to women living with HIV. Our data provide further encouragement for screening for HIV infection and initiation of ART before pregnancy to enhance immunity transferred to iHEU.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic Methods for Cryptosporidiosis in Low- and Middle-Income Countries: A Systematic Narrative Review.","authors":"Tewachew Awoke,Asnake Simieneh,Fregenet Tesfaye,Øystein Haarklau Johansen,Delfino Vubil,Berhanu Yitayew,Abel Abera Negash,Kurt Hanevik","doi":"10.1093/infdis/jiag205","DOIUrl":"https://doi.org/10.1093/infdis/jiag205","url":null,"abstract":"BACKGROUNDCryptosporidiosis is a major cause of diarrheal disease in low- and middle-income countries (LMICs), yet access to diagnostic testing is limited. Evidence on the diagnostic accuracy and operational feasibility of available tests is fragmented. We therefore systematically reviewed studies reporting on accuracy and feasibility of cryptosporidiosis diagnostic methods in LMICs.METHODSFollowing PRISMA guidelines, we systematically identified studies by searching databases and additional sources, screened abstracts, and publications using predefined inclusion criteria and assessed methodological quality using the QUADAS-2 tool.RESULTSOf 1687 unique records, 51 met our inclusion criteria. Most studies were conducted in Asia (49%) and Africa (45%), with 55% evaluating Cryptosporidium testing conducted consecutively near the point of care. Quality of reporting was poor overall, particularly regarding reference standards used for accuracy calculations. Few studies included sufficiently large sample sizes. Sensitivity of modified acid-fast stains was generally reported as low and varied widely across studies. The reported sensitivity of immunochromatographic lateral flow tests was 50-89% against PCR or quantitative assays, with specificities of 89-100%. Auramine fluorescence microscopy showed promising sensitivity and specificity, including in a prospective clinical diagnostic accuracy study. Only 5 studies (11%) addressed operational feasibility, of which 4 lacked original data and 1 evaluated total test turnaround times and cost-per-test calculations.CONCLUSIONSMethodological flaws and poor reporting limit the validity of many LMIC studies for cryptosporidiosis diagnostics, leaving substantial evidence gaps. Well-designed, adequately powered studies are needed to evaluate the diagnostic accuracy and operational feasibility of near-patient tests in these settings.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Schistosoma mansoni Infections Are Associated With Fecal Calprotectin Markers of Gut Inflammation After Accounting for HIV, Hepatitis B, and Malaria.","authors":"Lauren Wilburn,Hanh Lan Bui,Paul Akampurira,Reagan Ddamba,David W Oguttu,Betty Nabatte,Narcis B Kabatereine,Goylette F Chami","doi":"10.1093/infdis/jiag094","DOIUrl":"https://doi.org/10.1093/infdis/jiag094","url":null,"abstract":"BACKGROUNDThe role of gut inflammation for intestinal schistosomiasis remains poorly understood in chronically infected and repeatedly treated populations.METHODSWe conducted a cross-sectional study nested in the SchistoTrack cohort within Pakwach district, Uganda. In 2024, 640 participants aged 6-85 years were examined for Schistosoma mansoni by Kato-Katz. Fecal calprotectin (fCal) concentration was measured by enzyme-linked immunosorbent assays. Fecal calprotectin was analyzed as binary outcomes (detectable, ≥100 µg/g, >250 µg/g) and natural log-transformed continuous values. Co-endemic infections (malaria, HIV, hepatitis B [HBV]) and sociodemographic covariates were investigated in logistic regressions with covariate selection.RESULTS74.4% of participants had detectable fCal, 22.3% had fCal ≥100 µg/g, and 7% had fCal >250 µg/g. Schistosoma mansoni prevalence was 49.1%. Infection intensity was positively associated with all fCal outcomes (detectable: OR 1.20, ≥100 µg/g: OR 1.11, >250 µg/g: OR 1.26; continuous: β .06) while infection status was positively related to all but the continuous fCal outcome. HIV was associated with fCal ≥100 µg/g (OR 2.52), while malaria and HBV were uninformative.CONCLUSIONSSchistosoma mansoni infections are characterized by persistent, clinically concerning levels of gut inflammation in chronically infected populations with repeated praziquantel treatment. Integration of fCal thresholds into clinical guidelines may improve management of schistosomiasis-related morbidity.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of correlates of protection against gonococcal infection by comparative immunoprofiling of responses in experimental and clinical studies.","authors":"Samantha A McKeand,Fidel Ramirez Bencomo,Anthony Soc,Rebekah A Jones,Angela Thistlethwaite,Zhenyi Gu,Eunice Nduati,Eduard J Sanders,Ann E Jerse,Jeremy P Derrick,Christoph Tang","doi":"10.1093/infdis/jiag216","DOIUrl":"https://doi.org/10.1093/infdis/jiag216","url":null,"abstract":"BACKGROUNDNeisseria gonorrhoeae is an important cause of sexually transmitted infection with rising antimicrobial resistance. Epidemiological studies suggest that vaccines containing meningococcal outer membrane vesicles (OMVs), for example 4CMenB (Bexsero), offer partial cross-protection, but immune correlates of protection are unknown.METHODSWe used a murine genital tract infection model to compare systemic and mucosal responses after immunization with Bexsero, gonococcal OMVs (Ng OMVs) with alum, or alum alone. Vaccinated mice were challenged intravaginally with N. gonorrhoeae. Serum bactericidal activity (SBA) was measured, and antigen-specific IgG responses were profiled using custom gonococcal protein microarrays. Murine responses were compared with those in high-risk humans immunized with Bexsero and patients with gonococcal infection.RESULTSBexsero vaccination significantly accelerated bacterial clearance compared with Ng OMV or alum controls. Serum and vaginal IgG profiles were highly correlated, revealing distinct antigenic signatures between vaccine groups. Bexsero elicited responses to some gonococcal orthologs of its recombinant antigens (GNA1030, GNA2091, NHBA), whereas Ng OMVs induced responses to Opa, PilQ, and MtrE. While SBA did not correlate with accelerated clearance, there was an association between PMN influx to the genital tract and reduced bacterial load. Comparative analyses demonstrated concordance between antigen-specific IgG patterns in sera and vaginal washes, and between Bexsero-immunized mice and human vaccinees.CONCLUSIONSProtein microarrays combined with multivariate analysis identified antibody signatures associated with protection against gonococcal infection. Concordant patterns of murine and human IgG responses highlight the translational value of the mouse model for defining correlates of protection and guiding rational gonococcal vaccine development.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vancomycin-resistant Enterococcus often spreads from hospitalized patients into the local environment and less often spreads from the environment into patients.","authors":"Dwayne Seeram,Heekuk Park,Julian A Abrams,Anne-Catrin Uhlemann,Daniel E Freedberg","doi":"10.1093/infdis/jiag240","DOIUrl":"https://doi.org/10.1093/infdis/jiag240","url":null,"abstract":"BACKGROUNDUncertainty remains about how gut-based organisms such as vancomycin-resistant Enterococcus (VRE) are spread within the local hospital environment. We hypothesized that, in the medical intensive care unit (ICU), VRE is spread predominantly patient-to-environment rather than environment-to-patient.METHODSMedical ICU patients with sepsis and receiving broad-spectrum antibiotics were sampled via deep rectal swabs at ICU admission and on ICU days 3, 7, 14, and 30. Corresponding ICU room environmental samples were taken at the same timepoints. All samples were analyzed with 16S sequencing and selective culture, and VRE isolates were genetically characterized via whole genome sequencing (WGS).RESULTSThere were 680 samples gathered from 90 unique patients and their ICU rooms. 47/90 (52%) patients and 36/90 (40%) rooms showed VRE colonization at one or more timepoint. On 16S sequencing, Enterococcus relative abundance was enriched in room samples when the room housed a VRE positive patient (0.63% VRE(+) vs. <0.01% VRE(-), p<0.01). In a network analysis, patient and room Enterococcus were connected for VRE positive but not VRE negative patients. WGS identified 23 genetically distinct clusters of VRE. There were 3 events when distinct clusters appeared first in the patient gut and then in the room and 3 events when clusters appeared simultaneously in the gut and room; in no cases was a cluster first detected in the room.CONCLUSIONSWe detected three events when spread of genetically distinct VRE clusters from hospitalized patients into their local ICU environment but no reverse events. Effectiveness of infection prevention might be increased by gut-targeting interventions.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Host Mutational Adaptation of Mycobacterium Tuberculosis Complex Strains During Tuberculosis Infection.","authors":"Helen Zhang,Naomi Medina-Jaudes,Alicia Forcada-Nadal,Ewan M Harrison,Francesc Coll","doi":"10.1093/infdis/jiag209","DOIUrl":"https://doi.org/10.1093/infdis/jiag209","url":null,"abstract":"BACKGROUNDTuberculosis (TB) is the leading cause of death from an infectious disease worldwide. Mutations arising in Mycobacterium tuberculosis complex (MTBC) strains during TB infection provide a record of bacterial adaptations, such as those needed to survive the attack of the immune system and antibiotic therapies.METHODSWe conducted a meta-analysis of MTBC sequenced strains with multiple isolates from the same patient, sourced from published studies and TB Portals. We applied a convergent evolution approach to identify heavily mutated MTBC loci across patients and estimated the rates of drug resistance (DR) acquisition during treatment.RESULTSUsing 5882 high-quality genomes from 1044 patients with TB, we identified 21 genes, 25 operons, and 27 promoter regions statistically enriched by mutations compared with the rest of the genome, and additional loci with established and plausible adaptive roles approaching statistical significance. Significantly, these included multiple loci known to be involved in resistance to first-, second-, and last-line anti-TB drugs. Previously reported candidate drug-resistance and -tolerance genes (prpR, Rv2571c, fadD11, helY, ndhA, Rv0139, fadE5, bioF2, and mce1 operon) were also identified. Genes encoding regulators (phoR, whiB6, and mycP1) and effectors (espK and eccE1) of the virulence ESX-1 locus were frequently mutated in host. Fluoroquinolone resistance was acquired more frequently during treatment than resistance to any other anti-TB drug.CONCLUSIONSWe show that frequently mutated genes in MTBC reveal expected and newly discovered in host adaptations, predominantly associated with DR but also with pathogenesis. The higher resistance acquisition rate observed for fluoroquinolones may have important clinical relevance.The authors applied a within-host evolutionary approach to show that frequently mutated genes in Mycobacterium tuberculosis complex strains reveal expected and newly discovered in host adaptations, predominantly related to drug resistance but also in genes of the virulence ESX-1 locus.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CMV Immune Responses and Cognitive Impairment in People with HIV.","authors":"Lakshmi Chauhan,Debashis Ghosh,Beau Ances,Katherine Tassiopoulos,Kunling Wu,Adriana Weinberg,Kristine M Erlandson","doi":"10.1093/infdis/jiag239","DOIUrl":"https://doi.org/10.1093/infdis/jiag239","url":null,"abstract":"People with HIV (PWH) have an earlier occurrence of aging complications, including cognitive impairment (CI). Chronic immune activation from cytomegalovirus (CMV) may contribute to increased inflammation and CI. We explored this association using several measures of CMV immune response among PWH. In a case-control design, we compared CMV IgG, ELISpot, and flow cytometry between cases (subsequent CI) and controls (no CI). Baseline CMV IgG, CMV ELISpot, or flow measures were not associated with subsequent CI. This exploratory analysis supports larger studies using more nuanced immunophenotyping to clarify relationship between CMV and development of CI in PWH.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Delayed Antiretroviral Therapy Initiation on Anti-CD4 Autoantibodies in Antiretroviral Therapy-Naïve People With HIV.","authors":"Brian P Epling,Shweta Mistry,Birgit Grund,Jason V Baker,Carlos Brites,Julien Gras,Sandy Pillay,Blessing Uche,John A Chiorini,Andrea Lisco,Peter D Burbelo,Irini Sereti","doi":"10.1093/infdis/jiag235","DOIUrl":"https://doi.org/10.1093/infdis/jiag235","url":null,"abstract":"BACKGROUNDWe previously identified anti-CD4 autoantibodies in antiretroviral therapy (ART)-naïve people with HIV (PWH) with CD4<100 cells/µL using luciferase immunoprecipitation systems (LIPS). The influence of ART initiation on anti-CD4 autoantibodies and their impact on CD4 recovery in PWH with higher CD4 counts is unclear.METHODSIn the Strategic Timing of Antiretroviral Treatment (START) trial, ART-naïve PWH with CD4>500 cells/µL were randomized to start ART immediately (immediate) or delay until CD4<350 cells/µL or AIDS (deferred). In a subset of participants, we measured anti-CD4 autoantibodies using LIPS from plasma samples collected at baseline and month 24. We used logistic regression models to evaluate associations with the presence of anti-CD4 autoantibodies and to compare month 24 anti-CD4 autoantibodies between treatment groups. In the immediate group, the mean change in CD4 counts from baseline to month 24 was compared by baseline anti-CD4 autoantibody serostatus.RESULTSBaseline anti-CD4 autoantibody prevalence in 1199 participants (600 immediate, 599 deferred) was 41%; anti-CD4 autoantibodies were higher with recent HIV infection and among participants in Africa. At month 24, anti-CD4 autoantibody prevalence had decreased to 26% in the immediate and 31% in the deferred group (OR=1.91, p<0.001). Participants with recent HIV infection had larger decreases in anti-CD4 autoantibodies (p<0.001). There was no difference in CD4 recovery from baseline to month 24 by baseline anti-CD4 autoantibodies within the immediate group.CONCLUSIONSAnti-CD4 autoantibodies are common in untreated PWH with high CD4 counts; however, with ART use, their prevalence decreases. Anti-CD4 autoantibodies are not associated with CD4 recovery in PWH with CD4>500 cells/µL initiating ART.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147753348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of age and birth cohort on influenza A virus subtype-specific hospitalization rates, United States 2010-2025.","authors":"Alissa O'Halloran,Nicole Hood,Dawud Ujamaa,Angiezel Merced-Morales,Brian Gurbaxani,Pam Daily Kirley,Monica J Napoles,Nisha B Alden,Deborah Aragon,James Meek,Kimberly Yousey-Hindes,Kyle P Openo,Lucy S Witt,Maya L Monroe,Patricia A Ryan,Lauren Leegwater,Sarah Rojewski,Cynthia Kenyon,Ruth Lynfield,Mayvilynne Poblete,Zachary Q Landis,Bridget J Anderson,Adam J Rowe,Christina B Felsen,Brenda L Tesini,Khalil Harbi,Erica Wilson,Krista Lung,Nancy E Moran,Melissa Sutton,Ann Thomas,H Keipp Talbot,William Schaffner,Melanie Crossland,Kristen Olsen,Manish Patel,Alicia M Fry,Rebecca Kondor,Catherine Bozio,Carrie Reed,Lynnette Brammer,Alicia Budd,Brendan Flannery,Shikha Garg","doi":"10.1093/infdis/jiag232","DOIUrl":"https://doi.org/10.1093/infdis/jiag232","url":null,"abstract":"BACKGROUNDOlder individuals (≥65 years) are at greatest risk of severe influenza requiring hospitalization. Since 2009, influenza-associated hospitalization rates during A(H1N1)pdm09-predominant influenza seasons have been lower than during A(H3N2) -predominant seasons. .METHODSUsing laboratory-confirmed influenza hospitalization rates from U.S. population-based surveillance, we investigated the relative A(H1N1)pdm09 to A(H3N2) hospitalization rate ratios by patient year of age and birth cohort from 2010 through 2025.RESULTSResults suggest partial protection against A(H1N1)pdm09 hospitalizations relative to A(H3N2) hospitalizations among patients born before 1945 (pre-1945 birth cohorts), and among individuals born during 1994 through 2009. Impact of partial protection against A(H1N1)pdm09-associated hospitalizations has diminished over time among older adults, contributing to elevated influenza hospitalization rates during the 2024-2025 influenza season.CONCLUSIONSOur findings suggest that influenza A hospitalization rates may increase during future influenza seasons when both influenza A(H3N2) and A(H1N1) viruses circulate or following the emergence of novel A(H1N1)pdm09-like viruses.","PeriodicalId":501010,"journal":{"name":"The Journal of Infectious Diseases","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147753349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}