Influenza A (H3) illness and viral aerosol shedding from symptomatic naturally infected and experimentally infected cases.

Autor: Bueno de Mesquita PJ; University of Maryland School of Public Health, Maryland Institute for Applied Environmental Health, College Park, MD, USA., Nguyen-Van-Tam J; Division of Epidemiology and Public Heath, Health Protection and Influenza Research Group, University of Nottingham School of Medicine, Nottingham, UK., Killingley B; Division of Epidemiology and Public Heath, Health Protection and Influenza Research Group, University of Nottingham School of Medicine, Nottingham, UK., Enstone J; Division of Epidemiology and Public Heath, Health Protection and Influenza Research Group, University of Nottingham School of Medicine, Nottingham, UK., Lambkin-Williams R; hVIVO, London, UK., Gilbert AS; hVIVO, London, UK., Mann A; hVIVO, London, UK., Forni J; hVIVO, London, UK., Yan J; University of Maryland School of Public Health, Maryland Institute for Applied Environmental Health, College Park, MD, USA., Pantelic J; University of Maryland School of Public Health, Maryland Institute for Applied Environmental Health, College Park, MD, USA., Grantham ML; University of Maryland School of Public Health, Maryland Institute for Applied Environmental Health, College Park, MD, USA., Milton DK; University of Maryland School of Public Health, Maryland Institute for Applied Environmental Health, College Park, MD, USA.
Jazyk: angličtina
Zdroj: Influenza and other respiratory viruses [Influenza Other Respir Viruses] 2021 Jan; Vol. 15 (1), pp. 154-163. Date of Electronic Publication: 2020 Jul 23.
DOI: 10.1111/irv.12790
Abstrakt: Background: It has long been known that nasal inoculation with influenza A virus produces asymptomatic to febrile infections. Uncertainty persists about whether these infections are sufficiently similar to natural infections for studying human-to-human transmission.
Methods: We compared influenza A viral aerosol shedding from volunteers nasally inoculated with A/Wisconsin/2005 (H3N2) and college community adults naturally infected with influenza A/H3N2 (2012-2013), selected for influenza-like illness with objectively measured fever or a positive Quidel QuickVue A&B test. Propensity scores were used to control for differences in symptom presentation observed between experimentally and naturally infected groups.
Results: Eleven (28%) experimental and 71 (86%) natural cases shed into fine particle aerosols (P < .001). The geometric mean (geometric standard deviation) for viral positive fine aerosol samples from experimental and natural cases was 5.1E + 3 (4.72) and 3.9E + 4 (15.12) RNA copies/half hour, respectively. The 95th percentile shedding rate was 2.4 log 10 greater for naturally infected cases (1.4E + 07 vs 7.4E + 04). Certain influenza-like illness-related symptoms were associated with viral aerosol shedding. The almost complete lack of symptom severity distributional overlap between groups did not support propensity score-adjusted shedding comparisons.
Conclusions: Due to selection bias, the natural and experimental infections had limited symptom severity distributional overlap precluding valid, propensity score-adjusted comparison. Relative to the symptomatic naturally infected cases, where high aerosol shedders were found, experimental cases did not produce high aerosol shedders. Studying the frequency of aerosol shedding at the highest observed levels in natural infections without selection on symptoms or fever would support helpful comparisons.
(© 2020 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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