Ming Wang, 71, and his wife were on a cruise from Australia, taking a break after decades of running the family's Chinese restaurant in Papillion, Nebraska, when infected.

In the 74 days he was hospitalised before dying in June, doctors frantically tried various experimental approaches, including enrolling him in a study of an antiviral drug that ultimately showed promise.

"It was just touch and go. Everything they wanted to try we said yes, do it," says Wang's daughter, Anne Peterson.

"We would give anything to have him back but if what we and he went through would help future patients, that's what we want."

Patients are already benefiting.

Though more deaths are expected because of the recent surge in infections in the US and elsewhere, there also are signs death rates are declining and people who get the virus now are faring better than did those in the early months of the pandemic.

"Some of the reason we're doing better is because of the advances," says Dr Francis Collins, director of the US National Institutes of Health.

Several drugs have proved useful and doctors know more about how to care for the sickest patients, he says.

We're in the "stormy adolescence" phase of learning what treatments work - beyond infancy but not "all grown up either".

The nearly one million deaths attributed to coronavirus in nine months are far more than the 690,000 from AIDS or 400,000 from malaria in all of 2019.

They're trending just behind the 1.5 million from tuberculosis.

Wealth and power have not shielded rich countries from the awful power of the virus.

The United States is "the worst-hit country in the world" with more than seven million infections and more than 200,000 deaths, reflecting "the lack of success we have had in containing this outbreak", says Dr Anthony Fauci, the nation's top infectious disease specialist.

More than 40 per cent of US adults are at risk for severe disease from the virus because of high blood pressure and other conditions. It's not just old people in nursing homes dying, Fauci stresses.

Dr Jesse Goodman, a former US Food and Drug Administration chief scientist now at Georgetown University, agrees.

"Nobody should make a mistake about this" and think they're not at risk just because they may not personally know someone who has died or haven't witnessed what the virus can do firsthand, he says.

Although cases are rising, death rates seem to be falling, says Dr Cyrus Shahpar, a former US Centers for Disease Control and Prevention scientist.

The virus's true lethality - the infection fatality rate - isn't yet known because scientists don't know how many people have had it without showing symptoms.

What's often reported are case fatality rates - the portion of people who have tested positive and then gone on to die.

Comparing these from country to country is problematic because of differences in testing and vulnerable populations. Tracking them within a country over time also carries that risk but it can suggest trends.

"The US cumulative case fatality rate in April was around 5 per cent. Now we're around 3 per cent," Shahpar says.

In England, researchers report case fatality rates have fallen substantially since peaking in April. The rate in August was around 1.5 per cent versus more than 6 per cent six weeks earlier.

One reason is changing demographics: more cases these days are in younger people less likely to die from their infection.

Increased testing also is playing a role: as more people with mild or no symptoms are detected, it expands the number of known infections and shrinks the proportion that prove fatal.

It's clear that treatments also are affecting survival, many doctors say.

People who have died from COVID-19, especially ones who took part in studies, have helped reveal what drugs do or do not help.

Dexamethasone and similar steroids now are known to improve survival when used in hospitalised patients who need extra oxygen but might be harmful for less sick patients.

An antiviral drug, remdesivir, can speed recovery for severely ill patients, shaving four days off the average hospital stay.

Two anti-inflammatory drugs, one used in combination with remdesivir - the drug Wang helped test - also have been reported to help although results of those studies have not yet been published.

The jury is still out on convalescent plasma, which involves using antibody-rich blood from survivors to treat others. No large, high-quality studies have tested this well enough to know if it works.

Aside from drugs, "the case fatality rate is actually improving over time as physicians get more adept at taking care of these very sick patients", says Dr Gary Gibbons, director of the US National Heart, Lung and Blood Institute.

In hospitals, doctors know more now about ways to avoid using breathing machines, such as keeping patients on their bellies.

The best way to avoid dying from COVID-19 remains to avoid getting it and experience has shown simple measures advocated by health officials work.

Australian Associated Press