Paris (AFP)
Do not panic, but also do not underestimate: in the vast majority of cases, the disease caused by the coronavirus is mild, but it can also do great damage, especially in the most fragile, and ultimately saturate the hospitals, which would have dramatic consequences.
- Who is most at risk? -
Mortality increases markedly with age: this is shown by a large analysis published on February 24 by Chinese researchers in the American medical journal Jama.
Out of nearly 45,000 confirmed cases, the average mortality rate is 2.3%. But there are no deaths among children under the age of 10. Up to the age of 39, the mortality rate remains very low, at 0.2%, then drops to 0.4% in those in their forties, 1.3% in those aged 50-59, 3.6% in those aged 60- 69 years and 8% in the 70-79 age group.
People over the age of 80 are most at risk with a death rate of 14.8%.
Another risk factor: having a chronic disease (respiratory failure, heart disease, history of stroke, cancer ...).
Another Chinese study published on Monday in the journal The Lancet (which however concerns a limited number of patients, 191), looks at the factors associated with a risk of mortality.
"At an advanced age, having signs of sepsis (or sepsis, a very serious infection with organ failure, editor's note) on admission to hospital and underlying diseases such as hypertension and diabetes "were" important factors associated with patient deaths, "said one of the authors, Dr. Zhibo Liu.
Important point: the fact that all these people are more at risk than the others does not mean that contamination with the coronavirus would necessarily be fatal to them.
"When someone 85 years old dies of the coronavirus, it is not the coronavirus which kills him", but more often "the complications which reach organs which were not in good condition", says AFP Michel Cymes, doctor and TV host very popular in France.
Likewise, the millions of people who suffer from chronic diseases must be vigilant but not panic.
For French professor Jean-Christophe Lucet, the risk concerns above all patients suffering from severe forms of these diseases. "We must be extremely clear" on this point, he said to AFP.
- How many deaths can we expect? -
According to the February 24 study, the disease is mild in 80.9% of cases, "serious" in 13.8% of cases and "critical" in 4.7% of cases.
If one relates the number of deaths in the world to the total number of officially registered cases, Covid-19, a disease caused by the coronavirus, kills approximately 3.5% of the diagnosed patients, with disparities according to countries.
Conversely, out of more than 130,000 positive cases recorded worldwide since the start of the pandemic, already more than half have been cured, according to the American University Johns Hopkins, which keeps a daily count.
The supposed death rate from the disease must be taken with tweezers as it is not known how many people have actually been infected. Since many patients seem to develop few or no symptoms, their number is likely to be greater than the cases detected, which would therefore lower this rate.
If we take into account these undetected cases, "it probably gives a death rate around 1%," said the American Anthony Fauci, director of the National Institute of Infectious Diseases, Wednesday before the American Congress.
However, the danger of a disease does not only depend on the absolute death rate but also on its ability to spread more or less widely.
Even if only 1% of patients die, "it can make significant figures if 30% or 60% of a population is infected," said Dr Simon Cauchemez, of the Institut Pasteur in Paris.
- What differences with the flu? -
Despite close symptoms, it is wrong to think that the disease caused by the coronavirus is just a common flu.
First, everything shows that it is more deadly. "The flu has a mortality of 0.1%, and this disease is 10 times more deadly," warned Anthony Fauci. WHO estimates that seasonal flu kills between 290,000 and 650,000 people worldwide each year.
In addition, experts fear that the severe forms of Covid-19 may affect a larger part of the population than those of the flu.
"The older we are, the more fragile we are, the more we are exposed to severe forms but this can also happen to relatively young people who do not have chronic pathologies", underlines N.2 of the French Ministry of Health , Professor Jérôme Salomon.
According to a Chinese study - involving 1,099 patients - 41% of severe cases were between 15 and 49 years old and 31% between 50 and 64 years old (compared to 0.6% for those under 14 and 27% for those over 65) ).
Finally, the other difference is that "we are not protected" against Covid-19, adds Professor Salomon: there is "no vaccine, no treatment" and man is not naturally immune to this new virus, which his body has never encountered before.
Even if the flu and Covid-19 viruses are different, you can fight their spread in the same way: avoid shaking hands and kissing, washing your hands frequently, coughing or sneezing in your elbow or in a disposable handkerchief, wear a mask if you are sick ... This is called barrier measures.
- Will hospitals be overwhelmed? -
This is the main danger of the current pandemic: a sudden explosion of cases which would lead to a massive influx of patients into inexorably overwhelmed hospitals.
This would complicate not only the management of patients with severe forms of Covid-19, but also of all the others. And it would be even worse if the caregivers ran out, in the event of contamination of a large number of them.
"Because of this double factor - an overload of work with fewer staff - patients with urgent pathologies would no longer be treated in time and would risk dying," said Belgian intensive care doctor Philippe Devos to AFP.
On social networks, many doctors around the world are alarmed by the risk of saturation of hospitals.
To avoid the crash, they call for civic responsibility and insist on the importance of measures to fight the coronavirus: avoid gatherings, isolate oneself if one is sick, wash your hands, cough in your elbow ...
These alerts are summarized on Twitter by the keyword #FlattenTheCurve ("flatten the curve").
It means that everyone has their role to play in curbing the epidemic by spreading it over time. Objective: to ensure that the peak is less abrupt (this is the famous curve to flatten) and that the number of simultaneous cases does not exceed the capacities of the hospital system.
- What about domestic animals? -
The case of a dog tested "weakly positive" in Hong-Kong, when his owner was contaminated, raised questions about human-animal infections.
But scientists insist that this case is isolated and that no conclusions can be drawn from it.
"In the light of available scientific knowledge, there is no evidence that pets and farm animals play a role in the spread of the SARS-CoV-2 virus," French health agency Anses said on Wednesday. .
According to its experts, the detection of the virus in the nasal and oral cavities of the Hong Kong dog is not proof of the infection of the animal. They raise the possibility of "passive contamination" (survival of the virus on a mucosa without it replicating it), calling however for additional studies.
© 2020 AFP