As the COVID pandemic forced a close study of airborne transmission, new evidence has challenged the idea that many respiratory pathogens besides SARS-CoV-2 were only carried in the large respiratory droplets from coughs and sneezes of infected individuals. Rather, they also spread through virus-laden microscopic respiratory aerosols.
In a review published in Science, Chia Wang and colleagues discussed recent research regarding airborne transmission of respiratory viruses and how an improved understanding of aerosol transmission will enable better-informed controls to reduce and mitigate airborne transmission.
Most respiratory pathogens were until recently assumed to spread largely in large droplets expirated from an infectious person or transferred from contaminated surfaces. Public health recommendations in mitigating viral spread has, thus far, been guided by this understanding.
It is also known however, that a number of respiratory pathogens, such as influenza and the common cold, spread through infectious respiratory aerosols, which can remain suspended in the air, travelling further and for much longer, infecting those that inhale them.
According to a growing body of evidence, much of which gained from studying the spread of COVID, airborne transmission may be a more dominant mode of respiratory virus transmission than previously thought. Here, Wang et al. highlight how infectious aerosols are generated, travel throughout an environment and deliver their viral payloads to hosts. Before COVID, the maximum size for droplets to be classified as aerosols was 5 micrometres, but this has now been updated to 100 micrometres, because up to this size, droplets can remain suspended in the air for up to 5 seconds from a height of 1.5m and travel one metre to be inhaled by another.
The deal with this under-appreciated threat, the authors described ways to mitigate aerosol transmission at long and short ranges, including improvements to ventilation and airflows, air filtration, UV disinfection and personal face mask fit and design.
Source: News-Medical.Net
