Because we are going back to talking about coronavirus air transmission

WHO has proved open to the hypothesis that the new coronavirus can also be transmitted via aerosol. For example, in specific conditions such as closed and poorly ventilated places. But still more evidence and evaluations are needed

(photo: Clemente Marmorino / IPP / Eyepix Group / Barcroft Media via Getty Images) This is the biggest question that revolves around the pandemic from Covid-19. And so we still don't have a definitive answer. Is the new coronavirus transmitted by air, therefore through aerosol? According to 239 scientists, who sent an open letter to the World Health Organization (WHO) in the past few days, the answer is yes, as there is the possibility that the infection could occur through the dispersion of infected droplets in the air. And now the response, albeit very cautious, of the WHO has arrived: experts have confirmed that there is emerging evidence of the air transmission of the new coronavirus.

As we told you, in fact, at a press conference of the past few days during which WHO Director-General Tedros Adhanom Ghebreyesus said that the pandemic has not yet reached its peak, the WHO technical manager Benedetta Allegranzi said in this regard. "We are collaborating with many of the signatories of the letter," said the expert. “There is emerging evidence on this issue and we believe we must be open to this hypothesis and study the available evidence to understand its implications on the modalities of transmission and the precautions to be taken. There are some conditions in which air transmission cannot be excluded, such as in very crowded, closed and poorly ventilated places ".

But what exactly do you mean that the contagion can occur by airborne transmission? Since the beginning of the pandemic , the Who has stressed over and over again that the main route of transmission of the new coronavirus is from person to person by breathing , by that is the famous droplets , i.e. the droplets of saliva emitted when someone positive to the virus sneezes, coughs, and speaks. It goes without saying, then, that the viral particles can easily reach those in the immediate vicinity. And it is precisely for this reason that among the main measures to contain the spread of the virus, the Who recommends maintaining a safety distance from each other of at least one meter.

But if the transmission is by air (via aerosol) was really a possibility, and so one should give it weight as urge the 239 scientists in their appeal, then we should be careful also to the air we breathe, or better, pay particular attention to the closed and poorly ventilated environments. The droplet charges of viral particles, in fact, are relatively large and quite heavy (they have a diameter greater than 5 microns), and can therefore remain suspended in the air for a long period of time and for long distances, i.e. until the push of a cough or a sneeze runs out, and gravity has the better of me. The aerosol droplets are much smaller, since they will reach a diameter of less than 5 microns. Are, therefore, more reading, and they can remain suspended in air for long periods of time. Just think of the measles virus can also survive in the air even up to a few hours. The question to which we still do not have a definitive answer, however, is if the aerosol may contain an amount of viral particles able to infect and how long the new coronavirus is able to remain suspended in the air.

so Far according to Who, the transmission by air would be possible only under special conditions, such as medical procedures that generate aerosols . “Especially in the last two months we have said several times that we consider the transmission of airborne as possible, but not supported by solid evidence or clear-cut. There is a heated debate on this issue” , she explained to the New York Times, Benedetta Allegranzi, prior to the response date in the last press conference. After the letters of the 239 scientists, in fact, the world health organization has admitted that, with a lot of caution, this possibility, stressing however that further tests and assessments. But if this hypothesis were confirmed, the Who should change their guidelines to prevent the spread of the new coronavirus in crowded environments, closed and poorly ventilated.