L. Zane, who worked for three months at the Detroit Medical Center in the United States, noted that coronavirus patients are now getting sicker than in May.
The same conclusion was reached by Chaira Puebli, a researcher from northern Italy, 4,000 miles away.
Raphael Canton, a Spanish epidemiologist, is also surprised by the change, saying last month that the number of patients at his medical center was "very different".
Mortality rates have dropped in areas around the world where the Novel Coronavirus is centered, although the disease is now spreading rapidly in the form of a new epidemic.
Scientists are convinced that this change is real, but its causes and persistence remain a matter of debate.
"It's a trend or something, no one knows," said Joshua Barcos, an epidemiologist at the Boston University School of Medicine.
In China, according to initial reports, the rate was 7%, but it was based on patients being treated in hospitals, and when the epidemic began to spread, experts estimated that the death rate was close to 2 to 3%.
Now, according to the US Centers for Disease Control and Prevention (CDC), the rate is 0.65%, which does not include elements such as asymptomatic patients and mild cases in official statistics.
Joshua Barcos emphasizes that millions of deaths are possible despite low estimates, as the United States currently has one of the highest rates of corona virus in the world and the highest number of deaths there than any other country.
The United States accounts for more than 20 percent of the world's coronavirus deaths.
"As we enter a new phase of the epidemic, with the onset of winter and the opening of offices and educational institutions, it is difficult to say at this time that the death toll is at an all-time high," said Joshua Barcos. But young people spread the disease to their elders.
Medical officials point to a number of reasons for the drop in mortality, such as the growing number of young people whose immune system helps them recover.
Similarly, large-scale testing has led to early detection of cases and improved treatment strategies.
A prominent but currently unconfirmed idea came from preliminary research that we have not accurately estimated the risks of corona virus in humans and that part of the population is already partially immune to it, possibly The common cold is caused by corona viruses, childhood vaccinations or something else.
Another possibility that is considered important is that our environment has changed, ie the weather, the behavior or the virus itself.
The lethality of most viruses gradually declines for a variety of reasons, including lack of hosts, changes to the virus that make it less life-threatening, new therapies or vaccines.
According to experts, this will definitely happen with the Novel Corona virus, but it remains to be seen how long this will happen and how many more deaths.
But most scientists doubt that what we are seeing is based on genetic sequencing research.
One idea has been the subject of debate in recent days, reinforced by two research reports.
One study came from Detroit Medical Center's KL Zen and another from Italy, which was presented at the European Society of Clinical Microbiology and Infectious Diseases in late September.
Their findings show that social distance and the use of face masks have reduced the amount of virus doses reaching people, resulting in less severe disease.
While L. Zane and other doctors are investigating why the severity of code 19 in patients is decreasing, they have discovered a point that has changed dramatically over time and that is viral load.
During the treatment of 708 patients in early summer, their average viral load (a measure of the amount of virus in the body) was tested on a weekly basis by Nestl س Swab.
The higher the viral load in most infectious diseases such as Ebola, HIV / AIDS and hepatitis, the worse the outcome.
El Zen sees a ray of hope in the results of this study, such as whether it is succeeding in its efforts to reduce the severity of the corona virus.
Monica Gandhi, an epidemiologist at the University of California, Los Angeles, said that if the initial viral load was reduced, it was likely that people's bodies would be able to fight it more effectively.
He said that this indicates that the ability to prevent viral infections has improved and as a result, its severity in people has decreased.
One of the many secrets of the corona virus and the most important is the risk of death from the disease in an individual.
Smallpox has a 10 percent chance, Ebola 50 percent, and rabies about 100 percent, making it the world's deadliest epidemic.
In the corona virus it is very complicated because the rate varies dramatically everywhere due to time, country, region, age and other factors.
