title: Respiratory virus RNA is detectable in airborne and droplet particles.
abstract: Aerosol transmission routes of respiratory viruses have been classified by the WHO on the basis of equilibrium particle size. Droplet transmission is associated with particles sized >5 µm in diameter and airborne transmission is associated with particles sized ≤5 µm in diameter. Current infection control measures for respiratory viruses are directed at preventing droplet transmission, although epidemiological evidence suggests concurrent airborne transmission also occurs. Understanding the size of particles carrying viruses can be used to inform infection control procedures and therefore reduce virus transmission. This study determined the size of particles carrying respiratory viral RNA produced on coughing and breathing by 12 adults and 41 children with symptomatic respiratory infections. A modified six-stage Andersen Sampler collected expelled particles. Each stage was washed to recover samples for viral RNA extraction. Influenza A and B, parainfluenza 1, 2 and 3, respiratory syncytial virus (RSV), human metapneumovirus and human rhinoviruses (hRV) were detected using RT-PCR. On breathing, 58% of participants produced large particles (>5 µm) containing viral RNA and 80% produced small particles (≤5 µm) carrying viral RNA. On coughing, 57% of participants produced large particles containing viral RNA and 82% produced small particles containing viral RNA. Forty five percent of participants produced samples positive for hRV viral RNA and 26% of participants produced samples positive for viral RNA from parainfluenza viruses. This study demonstrates that individuals with symptomatic respiratory viral infections produce both large and small particles carrying viral RNA on coughing and breathing.
authors: School of Public Health and Community Medicine, The University of New South Wales, Sydney, New South Wales, Australia; Virology Division, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors: Jan
authors: J
authors: Gralton
authors: Euan R
authors: ER
authors: Tovey
authors: Mary-Louise
authors: ML
authors: McLaws
authors: William D
authors: WD
authors: Rawlinson
mesh_terms: D000293:Adolescent; D000328:Adult; D000391:Air Microbiology; D002648:Child; D002675:Child, Preschool; D003371:Cough / Q000821:virology; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D052638:Particulate Matter / Q000032:analysis*; D012327:RNA Virus Infections / Q000635:transmission* / Q000821:virology; D012328:RNA Viruses / Q000235:genetics*; D012367:RNA, Viral / Q000032:analysis*; D012141:Respiratory Tract Infections / Q000635:transmission* / Q000821:virology; D055815:Young Adult
chemical_list: D052638:Particulate Matter; D012367:RNA, Viral
keywords: airborne; particle; size; transmission; virus