Lai Jianyu, Bueno de Mesquita P Jacob, Hong Filbert, Ma Tianzhou, Cowling Benjamin J, Milton Donald K
Department of Global, Environmental, and Occupational Health, University of Maryland School of Public Health, College Park, Maryland, USA.
Department of Public Health, Roger Williams University, Bristol, Rhode Island, USA.
Influenza Other Respir Viruses. 2025 Jun;19(6):e70129. doi: 10.1111/irv.70129.
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.
We previously studied (A) volunteers intranasally inoculated with a dose of 5.5 logTCID 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.
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.
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.
在先前的一项研究中，经鼻腔接种流感的病例症状较轻，呼出气体气溶胶（EBA）中的病毒RNA载量低于患有典型流感样疾病的人。经鼻腔接种流感是否代表轻度自然流感感染尚不清楚。我们扩展了先前的分析，纳入了更广泛的社区获得性病例。
我们先前研究了（A）经鼻腔接种5.5 logTCID的甲型流感病毒/威斯康星/67/2005（H3N2）的志愿者，以及（B）2013年招募的包括发热在内的典型流感样疾病病例。我们现在增加了（C）2017 - 2019年大学宿舍居民及其接触者监测队列中的病例，以及（D）2019年来自大学健康中心的病例。所有病例均感染甲型流感（H3）。我们使用Gesundheit-II采样器收集30分钟的EBA样本。
监测队列（C）中的社区获得性病例排出的EBA病毒RNA更多，症状比接种病例（A）更明显，但排出的病毒RNA比2013年症状选择的自然病例（B）少，但比2019年的（D）病例少。尽管与2013年选择的病例（B）症状相似，但2019年感染后招募的社区获得性病例（D）的细气溶胶病毒RNA较低。
鼻腔接种流感病毒并未重现轻度自然感染中观察到的EBA病毒RNA排出或症状。甲型流感（H3）的流行毒株在有症状病例向细气溶胶中排出病毒的程度上可能逐年不同。需要新的模型，可能包括气溶胶接种，来研究人类呼吸道病毒气溶胶的排出情况。
