A new commentary published in the journal Clinical Infectious Diseases, and co-signed by 239 scientists from around the world, is calling for international health authorities to recognize COVID-19 can be spread by airborne transmission. Based on growing cluster case study data, the scientists call for greater mitigation measures to control indoor airborne spread of the virus.
Ever since the pandemic kicked off in early 2020, scientists have been debating whether SARS-CoV-2, the virus responsible for COVID-19, can be transmitted through the air. The question hinged on a technical distinction between larger respiratory droplets, which are too heavy to remain suspended in the air, and smaller particles called aerosols, which can stay airborne and travel around a space on air currents.
Measles is perhaps the most commonly referenced airborne infectious virus. We know it is wildly contagious and particles of the virus particles can be exhaled and remain airborne in an indoor space for up to two hours.
“A technical distinction is typically made between ‘transmission by respiratory droplets’ expelled through coughing or sneezing, relatively heavy – thus reaching relatively short distances – and assumed by WHO and other official bodies to be the main transmission mechanism for SARS-CoV-2 upon contact with them; and ‘airborne transmission’, which involves smaller particles suspended in the air (aerosols),” explains Jose Vazquez-Boland, an infectious disease expert from the University of Edinburgh.
In a newly published commentary piece, Lidia Morawska from the Queensland University of Technology and Donald Milton from the University of Maryland School of Public Health suggest there is an overwhelming volume of cluster case study evidence to show SARS-CoV-2 can be spread by some form of airborne transmission.
“Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are exhaled in microdroplets small enough to remain aloft in the air and pose a risk of exposure beyond 1 to 2 m (3.3 to 6.6 ft) by an infected person,” says Morawska. “For example, a recent study analyzed the data and video records in a restaurant where three separate groups of diners contracted COVID-19, observed no evidence of direct or indirect contact between the three groups, but modeled how the transmission occurred through the air.”
The commentary from the two researchers is co-signed by 239 experts around the world and it recommends three measures to help mitigate airborne transmission. First, it is suggested public indoor spaces provide “sufficient and effective ventilation” and recirculated air should be minimized in spaces such as hospitals, schools and workplaces. In many cases this can be as simple as leaving a door or window open.
The final recommendation is a reminder to avoid overcrowding in indoor public spaces. The greatest concern is heightened risk of transmission in enclosed environments such as public transportation, bars or cinemas.
https://newatlas.com/health-wellbeing/airborne-transmission-coronavirus-covid19-aerosol-indoor-safety/