The United States hit 200,000 coronavirus deaths on Tuesday, an nearly unthinkable milestone whose arrival underscored the failure of American leadership to contain the virus through spring and summer, said experts.
They also warned that with schools reopening and outdoor gatherings soon to be driven indoors by the coming cold, there could be more surges on the way.
Clinical trials for three vaccine candidates are under way, but it will take some time before vaccines will be widely distributed, they added, despite President Donald Trump's suggestion that a vaccine could be ready by election day on Nov 3.
"Every one of the 200,000 Americans killed by Covid-19 is a tragedy, and most of these deaths did not have to happen," said Dr Tom Frieden, previous director of the Centres for Disease Control and Prevention.
"There is no fairy-tale ending to this pandemicnot even a vaccine," he added on Twitter.
Instead, he and others advocated wearing a mask, continued social distancing, more strategic testing, rapid isolation, complete contact tracing and supportive quarantine to save lives and livelihoods.
Dr Frieden argued in a commentary the previous week that while the national positivity rate has droppedfrom a high of 20 per cent to 5 per cent nowAmerica is also losing the ability to track the virus, with less testing overall and no reliable information on who is being tested.
Mr Trump on Tuesday defended his administration's handling of the virus, blaming China for not stopping the virus at its borders and stating that the death toll could have been as high as 2.5 million without his leadership, he told newsmen on the South Lawn at the White House.
"You could have had a number that was substantially more. With all that being said, we shouldn't have had anybody," he added.
Mr Trump appeared to be referring to an Imperial College London model in March that predicted 2.2 million deaths in a worst-case scenario of an uncontrolled spread due to total government inactiona low bar to clear.
Johns Hopkins University epidemiologist Jennifer Nuzzo said: "The US represents less than 5 per cent of the world's population, but more than 20 per cent of Covid-19 deaths. It didn't have to be this way.
"Other countries used their resources to keep cases and deaths from accelerating. The US had these resources and more, but did not make use of them."
America's more than seven million coronavirus cases and over 200,000 deaths account for more than a fifth of the world's total.
In a Twitter post, Democratic presidential candidate Joe Biden slammed comments by Mr Trump at a rally in Ohio on Monday that the virus affected "virtually nobody".
Mr Biden said: "We lost 200,000 mums and dads, sons and daughters, friends and co-workers.
"And not a single one of them was a nobody."
Between 700 and 800 Americans are dying from Covid-19 daily, according to the Covid Tracking Project, down from the mid-August peak of around 1,200 daily deaths and all-time high of more than 2,000 in April.
But the Institute for Health Metrics and Evaluation (IHME) at the University of Washington projects a most likely scenario of 380,000 total deaths by Jan 1 next year, a number that can be lowered to 262,000 deaths if nearly everyone wears masks. If social distancing rules ease, the deaths could shoot up to 428,000, it predicts.
"Seasonality is the key driver, along with declined vigilance from individuals as we head into the winter," said IHME director Chris Murray, citing data from cities in the southern hemisphere and strong seasonal patterns in pneumonia trends.
"As we predicted several months ago, the fall-winter surge has begun in Europe. It hasn't yet kicked in in the US to the same degree... but everything that we see in the data tells us there will be that winter surge," he added in an interview with the Centre for Strategic and International Studies this week.