Worldwide, the disease caused by the new coronavirus (COVID-19) has cumulatively infected more than 50 million people and caused 1.2 million deaths.

The bad news is that the new coronavirus strain currently sweeping the world has shown in many ways that it is more transmissible than it first appeared;

The good news is that around the world, many medical institutions have observed that the fatality rate of COVID-19 continues to decline, and new crown patients admitted to the intensive care unit (ICU) now have a higher chance of surviving.

▲Related reading: The new crown mutant strain is sweeping the world, and "Science" confirms that it is more transmissible

Intensive care specialist Bharath Kumar Tirupakuzhi Vijayaraghavan, who works at the Apollo Main Hospital in India, saw as many as 35% of their Covid-19 wards die in April and about 70% of those on ventilators died;

Now, the mortality rate of patients on ventilators has dropped to 45% to 50%.

Derek Angus, an intensivist at the University of Pittsburgh, sees the same trend at his hospital.

Data on more than 20,000 cases collected by the NHS between March and June also shows that the chances of survival of critically ill patients are rising.

However, at the same time, these experts pointed out that the "magic medicine" has not appeared, and there has been no major breakthrough in medical solutions. What is the reason why COVID-19 seems to be less deadly?

Recently, the "Nature" magazine published a long report, which has been discussed in detail.

Hard-won treatment experience

Experts point to a shifting perception of COVID-19 that is important for improving treatment.

At the beginning of the outbreak, the new coronavirus was seen as a terrible new thing, and some unproven interventions were taken to save patients.

"The initial discussion about whether COVID-19 is a completely different and completely new disease has made things very complicated and distracted, and anyone can go off track."Dr. Vijayaraghavan thinks.

As for the detours taken, Dr Charlotte Summers, an intensive care specialist at the University of Cambridge, gave an example.

She used "furore" to describe the previous use of hydroxychloroquine in the treatment of new crowns. When some preliminary research suggested that the malaria drug appeared to help treat Covid-19, it was heavily touted by some despite the lack of strong evidence.

But the results of a large study exploring multiple new crown treatments, the RECOVERY clinical trial in the United Kingdom, released in June showed that hydroxychloroquine did not improve mortality in hospitalized patients with COVID-19.

The trial stopped enrolling patients in the hydroxychloroquine arm on June 5 after an interim analysis determined hydroxychloroquine lacked efficacy.

At the same time, the study and other findings also found that hydroxychloroquine may cause heart damage in some Covid-19 patients, especially when combined with the antibiotic azithromycin.

In Dr. Summers' view, the hundreds of hydroxychloroquine clinical trials that have been launched are wasting resources and energy that could have been spent elsewhere.

"Hydroxychloroquine has been abandoned for hospitalized patients, so we have one less thing to worry about," she said.

Time-proven drugs and regimens

In the early days of the epidemic, the "cytokine storm" was also a problem that deepened people's concerns.

This phenomenon refers to the excessive production of cytokines in some patients, triggering an excessive inflammatory response. So some doctors try to suppress the immune response with targeted therapies, such as inhibiting the activity of the cytokine IL-6.

But subsequent studies have shown that some severe COVID-19 patients do have elevated levels of IL-6, but not higher than other acute respiratory distress syndromes.

Therefore, Dr. Angus is not optimistic about the role of cytokine inhibitors: "For decades, researchers have been looking for targeted ways to suppress the immune response in critically ill patients,

But we've had two or three decades of failure to improve outcomes by blocking cytokine cascades. "

The results of clinical trials appear to confirm his claims. In a phase 2/3 clinical trial in hospitalized patients in the United States, the IL-6-blocking antibody sarilumab failed to produce significant improvements in critically ill patients.

"In just six months, I think we have replicated the results of the last 20 years of research in acute respiratory distress syndrome," concluded Dr. Marcus Schultz, an intensive care specialist at the University of Amsterdam Medical Center in the Netherlands.