The data was released on Thursday evening during Donald Trump's daily press briefing. According to the preliminary results of a study carried out in the United States, the coronavirus is not only sensitive to temperatures, but also to sun and humidity.
These various factors would greatly limit the survival of the virus on inert surfaces and in the air, an indicator that is necessarily positive as summer looms in the countries of the northern hemisphere.
"Our most striking observation to date is the powerful effect that sunlight appears to be killing the virus, both on surfaces and in the air," said senior Homeland Security official Bill Bryan, referring to this study conducted at the National Biodefense Analysis and Countermeasures Center.
"Several studies have already corroborated the idea of a seasonal slowdown in contamination linked to rising temperatures, points Antoine Flahault, specialist in epidemic diseases and director of the Institute of Global Health at the University of Geneva. The novelty here is to consider more parameters. "
Swimming allowed
The role of the sun's rays, in particular, was previously unknown. The first results seem to show that they could spend the survival time of the virus on a smooth surface, such as a door handle, from just a few hours to a few minutes.
In the laboratory, it is also possible to keep droplets of the virus in the air without them crashing into the ground. In these particular conditions, the simple light of the sun also seems to drastically reduce its ability to survive. The coronavirus would lose half its power in a minute and a half, instead of an hour.
Another lesson: the virus does not resist humidity well. This is good news for the summer as it would mean that bathing waters, rivers, lakes and other swimming pools could not be contaminated by the coronavirus. The flu, which is an exception in this area, is transmissible in the aquatic environment.
Newsletter - The essentials of the news
Every morning, the news seen by Le ParisienI'm registering
Your email address is collected by Le Parisien to allow you to receive our news and commercial offers. Find out more
VIDEO. When Trump suggests injecting disinfectants or UV
These various elements suggest that summer could have a greater effect than expected on the rate of contagion. This, in the absence of strict sanitary measures, is generally estimated around three. Each infected person, on average, would infect three others.
"So far, various texts have estimated that the force of seasonal braking could allow this rate to be lowered to around 1.8, analyzes Antoine Flahault. If the first results of this study are to be believed, it could be even less. "
Caution
However, only a rate lower than 1 would reduce and then put an end to contamination. For the moment, nothing indicates that summer would make it possible. Hence the caution displayed by the American authorities on Thursday evening, who dismissed any lifting of social distancing measures.
PODCAST. Donald Trump and the coronavirus: a slow awareness
"In addition, even if it is interesting to have added factors such as humidity and sunshine to temperatures, other conditions necessarily complicate the equation," recalls the researcher. A change of season implies new habits: for example, we will move from central heating to the use of air conditioning. As many parameters as the American study, as promising as it is, would be hard to take into account.