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Phase 2 and Risks of Coronavirus contagion

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Here in Italy, where I live, from 4 May, we have entered a second phase of the Coronavirus emergency administration, with the reopening of factories, home delivery of food and the possibility of meeting relatives.

From Monday 18 May, given that the statistics on the trend of infections are currently positive, we will have a further reopening. All commercial activities will restart, including hairdressers and beauty centers. In addition, group training and sports activities will be granted.

People's reactions are very varied. There are those who consider the measures adopted so far too severe and are therefore very happy with this general reopening. Others, however, fear that negligence and superficiality may compromise safety conditions and provoke a new surge in infections.

But let's briefly see what the real risks may be in some specific situations and what we must do to protect our health and that of others as much as possible.


Meetings and lunches/dinners

One of the situations with the greatest risk exposure is that in which a group of people meet to eat together.

In this regard, the Japanese television NHK has carried out an experiment, shown in a video that has totaled 14 million views on Twitter. The authors organized a buffet with 10 people and sprinkled the hands of one of the participants with special fluorescent paint, not visible to the naked eye, but with a special ultraviolet light. None of them used safety devices, they had just some protective goggles.

After only half an hour from the beginning of the banquet, the fluorescent paint was on everyone's hands and also on the faces.

You can find HERE this very interesting experiment. I recommend you to watch the video because it is really shocking and gives a very good idea of ​​how simple it is to infect or be infected.


Cough

What happens if someone coughs without a mask inside a closed place?

A 3D simulation of Aalto University, Finnish Meteorological Institute (FMI) and Technical and Innovation Center VTT and Helsinki University showed this.

In the video, a cough is simulated in a supermarket aisle.
The yellowish little balls correspond to droplets of less than 20 micrometers and are the ones that spread faster, both along the corridor and invading the neighboring lanes. Based on the fluid dynamic characteristics typical of coughs and indoor ventilation, according to researchers' calculations, the cloud takes several minutes to dilute and disperse within the supermarket.

Some infectious disease experts have pointed out that the model shows the spread of the droplets but says nothing about its viral load. This is a very important clarification, since, in order to contract the virus, one must come into contact with a certain dose of pathogen and it is much more likely that this will happen if one is in the vicinity of the infected subject who coughs.

It's clear that, even in this case, the use of the masks is of fundamental importance to reduce the risk of interference. Furthermore, the shrewdness of coughing in the bend of the elbow avoids, in any case, the massive diffusion of the particles.


Talking

Even if we don't cough or sneeze, we can still transmit or receive potentially infected droplets just by talking.

This is demonstrated by a study published in The New England Journal of Medicine made by researchers from the National Institutes of Health. A video was produced (you can find it HERE) which, thanks to laser technology, shows the quantity of droplets emitted from the mouth of a man who has been asked to pronounce the phrase "stay healthy" at different volumes of voice.
The result was 347 droplets out loud and 227 droplets in a low voice for each still image.

The researchers also observed that particles smaller than 20 micrometers behave differently from larger ones, remaining suspended in the air longer.

Precisely for this reason, even covering mouth with a mask may not be sufficient to avoid possible contamination. In this case, it's advisable to keep a safety distance of at least one meter from your interlocutor.


Beach and Sea

Summer is approaching and soon we will have to manage meetings between families, also from different regions.

How will we have to behave on the beach and at sea?

It's clear that it will not be so easy to keep the correct distances on vacation.
It will be necessary that the umbrellas are spaced a few meters apart, also in this case the use of the masks and the main rule not to create gatherings will be important.
What should be avoided is mainly the risk of a spread of the extrafamilial contagion. In addition, operators will have to ensure the sanitization of all equipment with alcohol or sodium hypochlorite based solutions.

If people who live in the same house and stay under the same umbrella don't have to wear a mask or keep their distance, precautions must absolutely be taken with friends and acquaintances.

The same goes for swimming in the sea: there is no need to create gatherings and the risk at sea is not less than what exists on the beach.

And can ventilation increase or reduce the risk of infection?

According to expert Italian epidemiologists Pier Luigi Lopalco and Roberto Cauda, ​​ventilation is not a negative element: it's thanks to the greater aeration that the spread of many viruses is reduced in summer. In general, the theory that contagion on the beach or at sea can take place through tiny saliva particles suspended in the air (the so-called aerosol), is rather remote. A recent study conducted by the Cnr Institute of Atmospheric and Climate Sciences, published on Atmosphere, found that outdoors the probability of transmission of the virus with this mechanism is very low.

Already for other viruses and pathogens it has been shown that in summer transmission is reduced also due to the fact that we spend much more time outdoors and in highly ventilated environments. And this, in all probability, could also apply to the Covid-19. The cold, in fact, unlike the heat, dries the mucous membranes and can compromise the mucociliary clearance, our first shield against pathogens. We are talking about a thin layer of mucus that imprisons pathogens which, thanks to particular hair cells, conveys them to the stomach and then disarms them.

On the contrary, great attention must be paid in closed environments, because if there are people infected, the risk of transmission also via aerosol could increase: for this reason, good ventilation of the interior spaces is important.

Thanks to all of you for reading my article.

If you liked it, share it on your blog and write me a comment with your impressions.

See you soon!

GM


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Credits @doze