What happened today seemed impossible to many Americans six months ago.

When Dr. Anthony Fauci predicted in March that COVID-19 could kill 200,000 people in the U.S., skeptics lambasted him and accused him of fearmongering.

But Fauci was right. And the U.S. reached that bleak milestone much earlier than some experts predicted.

Since the first known U.S. COVID-19 death on February 6, an average of more than 858 people have died from the disease every day.

Many of those victims died without loved ones in hospital rooms. Countless others never had a proper funeral, with mourners grieving remotely online.

COVID-19 is now the second-leading cause of death in the U.S., just after heart disease, according to the University of Washington's Institute for Health Metrics and Evaluation (IHME).

What happens next with the pandemic largely depends on personal responsibility and how much Americans are willing to fight this battle together.

Already, COVID-19 has killed more people in the U.S. than Americans killed in battle during the five most recent wars combined: the Korean War, the Vietnam War, the Iraq War, the War in Afghanistan and the Persian Gulf War.

The loss of life is like suffering the effects of 109 Hurricane Katrinas. Or enduring the 9/11 attacks every day for 66 days.

And researchers project almost 180,000 additional COVID-19 deaths by January 1.

But it doesn't have to be that way.

"Increasing mask use to 95% can save nearly 115,000 lives, reducing that expected number of deaths by 62.7%," the IHME said.

And the same mask wearing, physical distancing and hand washing that protect against COVID-19 can also help avert a flu-and-coronavirus "twin-demic" that could overwhelm the health care system.

"We have to stay strong and do the things that could decrease the spread," said pediatrician Dr. Brett Giroir, the White House coronavirus task force's testing czar.

"Number 1: Wearing a mask when we can't physically distance. Number 2: Avoiding crowds. Number 3: Hygiene. And with smart testing, we can flatten the curve and slow the spread," Giroir said.

"We do have a formula to reduce the deaths, reduce the cases. But we all have to be disciplined and diligent to make sure we obey that every single day."