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Coronavirus I Health assumes the evidence of contagion by aerosols

The Ministry of Health has included scientific evidence on the transmission of the coronavirus through aerosols that people give off when speak, sing or shout. Further, has established that the risk increases in closed, crowded, and especially poorly ventilated spaces.

This warning has been logged in the last update of the scientific-technical information document on coronavirus disease. In it, Health has included a broad section, 1.3.2.1 Transmission by respiratory secretions: drops and aerosols, where it explains all the current evidence on aerosol transmission that has been published throughout the pandemic andpedmiologists and experts in this matter.

The size of the aerosols

“Based on the sizes of these aerosols, aerodynamic behavior is different. It is considered that only drops greater than 100 microns have “ballistic” behavior, descending to the ground in a few seconds due to the effect of gravity and can travel a maximum distance of two meters from the emitter. These drops could reach a susceptible person who was nearby, impacting somewhere (eyes, mouth, nose) from which they could cause infection ”, the report states.

All other respiratory emissions below 100 microns are considered an aerosol: “The aerosols that are produced when breathing or speaking are more than 80-90% very small (<2.5 microns), coming from the lungs and on average about 500 are generated per liter of exhaled air. When coughing produces 3,000 particles and when sneezing 40,000, mostly small (1-10 microns), coming from the upper respiratory tract (19,21) ”, the document states.

Conditions for transmission by aerosols

According to the criteria established by the scientific community, the conditions for the transmission of the coronavirus by means of aerosols to be demonstrated are three. First, that the microorganisms contained in the aerosols are in sufficient quantity and demonstrate their ability to generate infection; Secondly, that the aerosols produced by breathing or speaking are more than 80-90% very small (<2.5 microns), coming from the lungs and on average about 500 are generated per liter of exhaled air. Coughing produces 3,000 particles and sneezing 40,000, mostly small (1-10 microns), from the upper respiratory tract (19,21). By last, that the target tissues to these microorganisms are accessible.

Scientific evidence

With these indications, the Ministry of Health concludes the section ‘1.3.2.1 Transmission by respiratory secretions: drops and aerosols’: “In In the current state of scientific knowledge, there is consistent scientific evidence that allows us to affirm that the transmission of the SARS-CoV-2 virus by aerosols should be considered an additional route of transmission to those already recognized previously (contact with respiratory secretions, fomites) ”.

“These aerosols could both impact and settle on the conjunctiva and mucosa of the upper respiratory tract, as well as be inhaled reaching any part of the respiratory tract. The risk of this transmission increases in the short distance, in closed and crowded environments, especially poorly ventilated, and if activities that increase the generation of aerosols are carried out, such as doing physical exercise, talking loudly, shouting or singing ”, concludes the aerosol section included within the document of scientific-technical information on coronavirus disease.