Close-range exposure to a COVID-19 carrier: transmission trends in the respiratory tract and estimation of infectious dose

Basu, S.

How respiratory physiology and airflow therein proceed to impact SARS-CoV-2 transmission, leading to the initial infection, is an open question. An answer can help determine the susceptibility of an individual on exposure to a COVID-2019 carrier and can also quantify the still-unknown infectious dose for the disease. Combining computational fluid mechanics-based tracking of respiratory transport in anatomic domains with sputum assessment data from hospitalized patients and earlier measurements of ejecta size distribution during regular speech - this study shows that targeted deposition at the initial nasopharyngeal infection sites peaks over the droplet size range of 2.5 - 19 , and reveals that the number of virions that can establish the infection is at most of O(100).