The main form of transmission of the coronavirus is by air – Telam

The route of transmission of the coronavirus that most scientific evidence has gathered during this pandemic year is through the air “which does not mean that the virus travels for miles to infect”, but rather that we breathe “invisible smoke (aerosols)” that comes out of the infected person when we are close or that it accumulates in closed places, explained to Tlam the Spanish researcher Jos Luis Jimnez, one of the largest world references on the subject.

A professor at the University of Colorado, United States, and one of 239 scientists who have called on the World Health Organization (WHO) to recognize the prominent role aerosols play in the pandemic, Jimnez said review in dialogue with Tlam certain key concepts to improve the care in the face of the second wave in front of the country.

– Tlam: There are three recognized forms of contagion: by surfaces, by large droplets and by aerosols What scientific evidence has been collected on each of them to date?
– Jos Luis Jimnez: Regarding the three forms of contagion, the CDC (Centers for Disease Control and Prevention of the United States) already declared last year and reiterated forcefully this week that contagion by surfaces is difficult and that there is no has no proven case.

As for the two that remain, the overwhelming evidence is the contagion through the air, from the breathing of aerosols. There is a lot of evidence for this: cases of super contagion or long distance transmission (for example in quarantine hotels like a country in New Zealand), that people without symptoms (by not coughing or not coughing) ‘not sneezing) simply emit aerosols and we know they are contagious, or the transmission is much higher indoors than in open spaces. All this can only be explained if the contagion is by air.

“At the start of the pandemic, it was said a lot that it was transmitted through contact with infected surfaces, so seeing surfaces disinfected gives a sense of security that today we know to be false.” “

Animals such as ferrets were also found to be infected, which could only have happened from the air.

The evidence for contagion by ballistic droplets, the large droplets, is very weak; It is therefore scandalous that a year after the start of the pandemic, the WHO continues to say that it is the main route of contagion.

What does it mean that the virus is in the air?
– JLJ: This is not a ghostly definition, it does not mean that the virus will travel for miles and come to infect; This means that infected people come in the form of invisible smoke which can contain the virus with the ability to infect; that smoke is respiratory aerosols, they are very small, invisible particles that remain floating in the air.

Now when do you breathe a lot of aerosols from each other? In two situations: when you are very close, especially without a mask (chin strap), or when you share the air in a closed room, because the enclosed space traps the air that the person exhales. These are two very common and frequent situations.

T: How can we reduce contagion?
– JLJ: The first point is to understand that everyone exhales this invisible smoke and that we must try not to breathe it. Harm reduction measures are not that difficult, but they are not applied. The first thing to do is to do everything you can outdoors, from a distance and with masks. Courses, work reunions, family reunions, everything must be done under these conditions.

The mask must be well attached to our face, especially around the nose. If all the air we breathe passes through the mask, the virus can “stick” to this fabric, while if we wear it with holes, it does not do its job well.

The mask should always be used indoors or when we enter places where someone has been or someone will come later (so we do not leave viruses behind).

Outdoors, for example, on a deck or patio, I should use it if I am within two meters of another person.

If I’m in an indoor space, I have to keep the number of people as low as possible and ventilate, which means the outside air comes in and the contaminated air comes out.

To see if we are ventilating well, one possibility is to measure carbon dioxide (CO2) which will tell us how much air is exhaled.

If it cannot be ventilated, it must be filtered; for this there are specific devices such as hepa filters or filters with a fan that can work well.

And we must avoid two types of things: chemical techniques which use ions, plasmas, hydroxyl, photocatalysis, because they are dangerous because they can produce toxic compounds; and we must also avoid putting disinfectants in the air such as ozone, hydrogen peroxide or chlorine dioxide, all this will serve to disinfect surfaces but not the air; it’s dangerous.

– T: Why have people integrated the use of alcoholic gel more than ventilation?
– JLJ: I think that’s because at the start of the pandemic, it was said a lot that it is spread through contact with infected surfaces, so seeing surfaces disinfect gives a sense of security that we now know to be false.

This fear has remained and now it is very difficult to suppress it; Hand washing is fine, we all agree on that, but obsessive cleaning of surfaces was pointless. And that is partly the responsibility of WHO.

– T: So outside, I also have to wear a chin strap.
– JLJ: It depends, if you are in the middle of a mountain with no one, in principle, it is not necessary. But if you are walking in a city and people pass you by, or if you are in a bar or on a terrace with friends, yes. One would have to imagine that the others smoke and that, to the extent that one can smell the cigarette, then one can inhale the aerosols that the other exhales.

– T: If I don’t have a CO2 meter, how can I make sure that a space is well ventilated?
– JLJ: This is a problem because if you feel the current, especially in winter, the most common is that people do not resist and close everything.

Therefore, together with a group, we started to insist on measuring CO2. Taking into account the fact that in the open air, the measurement is 400 ppm, the ideal would be that in the environment in which we find ourselves, it does not exceed 700 ppm; Most of the time when you measure you find over 1500 ppm, and in a car it can go up to 5000 ppm.

The device is not very expensive and in a school they can buy two and periodically measure the classrooms and learn; For example, on a windless day, you may need to open three six-inch windows, but on a windy day, opening them four inches may be sufficient.