https://www.npr.org/sections/health-shots/2020/10/20/925441975/studies-point-to-big-drop-in-covid-19-death-rates - https://www.npr.org/sections/health-shots/2020/10/20/925441975/studies-point-to-big-drop-in-covid-19-death-rates

Two new peer-reviewed studies are showing a sharp drop in mortality among hospitalized COVID-19 patients. The drop is seen in all groups, including older patients and those with underlying conditions, suggesting that physicians are getting better at helping patients survive their illness.

"We find that the death rate has gone down substantially," says  https://nyulangone.org/doctors/1841334810/leora-horwitz" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(80, 118, 184); text-decoration: none; - Leora Horwitz , a doctor who studies population health at New York University's Grossman School of Medicine and an author on one of the studies, which looked at thousands of patients from March to August.

The study, which was of a single health system, finds that mortality has dropped among hospitalized patients by 18 percentage points since the pandemic began. Patients in the study had a 25.6% chance of dying at the start of the pandemic; they now have a 7.6% chance.

That is very good news! Thanks for that ksc!  I've said all along that until we come up with an effective vaccine we needed effective treatments!  That looks like it's happening. 

DJ-With all respect-most likely reason may be younger patients...

This story-via google translate is from Poland;

Poland

The second wave is also stronger than the first in Poland. On Saturday there were almost 10,000 new infections for 38 million inhabitants. This means that the country is not in the top 5 of the most affected EU countries, but there is a chance that the health care system will fail here first.

The Polish Academy of Sciences issued an alarming warning last week: "There is a situation in which very soon many people will die without help at home or even on the street." The first cry for help from hospitals came this weekend.

The public channel TVN listened to the radio communications of ambulances and heard shocking reports. Ambulances waiting in a hospital driveway for eight hours, a stroke patient treated on a stretcher, a critically ill corona patient left unprotected in a wheelchair in a corridor.

Hospitals across the country are in danger of being unable to cope. An emergency hospital is being rapidly built in the National Stadium in Warsaw. 500 to 1000 beds must be placed in the meeting rooms of the stadium. Emergency solutions are also being worked on in other parts of the country.

There are likely several things happening to reduce mortality: 

a) earlier diagnosis and self-admission to hospitals - at the outset of the pandemic, I believe many may have confused COVID-19 symptoms with other, less serious respiratory illnesses....this likely caused them to delay seeking care, so by the time they were admitted, the disease had progressed further. 

b) improved knowledge of the natural history of the virus & its disease - at the outset, we didn't know much about this virus & were struggling to even test effectively.  We now have much improved testing, which helps diagnostics. 

c)  improvements in medical treatment - in addition to the much-feared ventilators, the Brits have shown that CPAP machines are effective for maintaining oxygenation (I believe PM Boris Johnson was treated in this manner).  Other recent improvements include steroids to counter-act the cytokine storm, plasma transfusion and remdesivir, although I don't think the last has been proved to reduce death. 

d)  younger patients - as DJ points out, the newest wave seems to be younger patients than what we have seen at the outset of the pandemic.   Pandemic fatigue seems to be taking place across the globe, so more young patients are surfacing. 

Other factors could include a slight attenuation of the lethality of the virus due to natural forces such as mutation and genetic drift.  This is a very good, although deep, paper that discusses how COVID-19 and SARS-CoV2 may become endemic upon humanity: 

https://theconversation.com/covid-19-will-probably-become-endemic-heres-what-that-means-146435 - https://theconversation.com/covid-19-will-probably-become-endemic-heres-what-that-means-146435

This one is also enlightening, for true virus geeks only!!  

https://science.sciencemag.org/content/early/2020/10/13/science.abe5960 - https://science.sciencemag.org/content/early/2020/10/13/science.abe5960