![]() They may carry virions, in proportion to the concentration of virions in the fluids from which they originate. They consist principally of saliva, hydrated mucus and/or lung surfactant, meaning they are mostly water with some carbohydrates, proteins and salts. The content of the droplets depends on their origin within the respiratory tract. At two ends of the spectrum, are small droplets (aerosols) that float and large droplets that rapidly fall to the ground under gravity. Unfortunately, the World Health Organization (WHO) was initially reticent to acknowledge the expertise of non-clinical aerosol scientists and explicitly recognise SARS-CoV-2 as an airborne pathogen, delaying important IPC mitigation measures in both healthcare and community settings.] Science of airborne disease transmissionĪny respiratory activity (including shallow breathing) emits particles of various sizes defined loosely by droplet size and aerodynamic properties. This understanding subsequently helped explain several observations about the pandemic, including indoor super-spreading events instances of long-range transmission and the tendency of the virus to transmit during the pre-symptomatic phase of infection. These assumptions aligned with longstanding teaching within the international Infection Prevention and Control (IPC) community that respiratory viruses generally spread via large respiratory droplets that fall rapidly to the ground within 1–2 metres of the source (“droplet transmission”).īy March 2020, aerosol scientists were publicly arguing that SARS-CoV-2 and other respiratory viruses also spread via tiny respiratory droplets that remain suspended in the air for longer periods (“airborne transmission”).] Significantly, they noted such tiny droplets (“aerosols”) are emitted during normal breathing and talking, even without coughing, sneezing or “aerosol generating procedures”. These risk reduction measures assumed the virus spread via close contact, contaminated surfaces and large droplets of saliva emitted during coughing and sneezing. A media release from New Zealand’s Ministry of Health on 24 January 2020 noted the virus caused pneumonia.] It advised the public to “take steps to reduce their risk of infection”, including by “regularly washing your hands, covering your mouth and nose when you sneeze”, staying home when sick and “avoiding close contact with anyone with cold or flu-like symptoms”. In early January 2020, news filtered through to the general public of a disease outbreak caused by a novel coronavirus centred around a live animal market in Wuhan, China. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |