(CNN) - Once again, Covid-19 deaths are rising after weeks of record-breaking new cases and hospitalizations.
"This epidemic is now out of control. And it's out of control mostly because of our own behavior," said William Haseltine, chairman and president of ACCESS Health International.
"People have not taken the consistent warnings of our health officials seriously. They are gathering in private and in public places without adequate protection. They are ignoring the advice."
At least 30 states suffered higher rates of new deaths this past week compared to the previous week, according to data from Johns Hopkins University.
In 12 of those states, the increase in deaths was at least 50%: Washington, Idaho, Montana, South Dakota, Texas, Mississippi, Michigan, Ohio, Maine, Virginia, West Virginia and Alaska.
And test positivity rates -- an indicator of how rampantly a virus is spreading -- remains stubbornly high in more than 30 states.
'It's not that complicated'
If Americans want schools to safely reopen and the economy to improve, they must get more serious about personal responsibility, health experts say.
"You have to do more than just wear masks and keep social distancing. You have to minimize your contact with as many people as possible," ACCESS Health's Haseltine said.
"It's not that complicated. But it is hard to do psychologically. It's hard to do sociologically. And it's extremely hard to do for young people."
"And if you do have to work," he said, "you have to assure that the workplace is safe and you can work safely at a distance."
Keeping a safe work environment and reducing your contact with others "are the two most important things you can do in addition to wearing masks and keeping your 6-foot distance," said Haseltine.
Coronavirus is 'widespread' in rural areas, too
More than 4.6 million Americans have been infected with Covid-19, and more than 154,000 have died, according to Johns Hopkins data.
And what used to be an urban problem has spread to rural communities.
"It's extraordinarily widespread," said Dr. Deborah Birx, the White House coronavirus response coordinator.
"So everybody who lives in a rural area, you are not immune or protected from this virus. And that is why we keep saying, no matter where you live in America, you need to wear a mask and socially distance."
At least 30 states have paused their reopening plans or imposed new restrictions as coronavirus remains out of control.
Yet many people "aren't wearing masks. They aren't distancing," said Dr. James Phillips, a physician and assistant professor at George Washington University Hospital.
"I'm concerned that the complacency that we've seen with coronavirus has led to these mass gatherings and a general disagreement with the science."
At this point, hard-hit areas should enact another round of stay-at-home orders to try to get the virus under control, Phillips said.
"What I'm concerned about primarily is the fact that we haven't controlled this virus in a serious way," he said.
"We're seeing rises in a lot of states, and now we're talking about reopening schools and colleges in the midst of that -- which I think is going to compound our problem significantly."
As one school district reopens, 260 employees infected or exposed
In Gwinnett County, Georgia, where some parents protested in favor of in-person classes, at least 260 school district employees tested positive for the virus or were in contact with someone infected, a district spokeswoman said.
That announcement came days after teachers returned to classrooms for in-person pre-planning, CNN affiliate WSB reported.
Across the country, some students have already tested positive as the school year begins.
At Greenfield-Central Junior High School in Indiana, a student tested positive on the first day of class -- prompting school officials to isolate the child and start tracking who may have come into close contact with the infected student.
In Mississippi, a high school student tested positive during the first week of classes, the Corinth School District said.
The in-person classes came after CDC guidelines laid out reasons for reopening schools, though it said places with significant, uncontrolled transmission of the virus should consider keeping school buildings closed.
The guidelines said children don't suffer much from coronavirus but suffer from being out of school.
The CDC guidelines also said children are less likely to spread the virus than adults -- but research suggests otherwise.
In Florida's Miami-Dade County, one of hardest-hit places in the country, the superintendent said students will continue virtual learning until at least October.
Why some people should wear face masks at home
Birx said some Americans who are asymptomatic or pre-symptomatic have unknowingly infected others in their household.
This can be especially dangerous if the virus eventually gets passed to elderly relatives or family members with underlying health problems.
So people who live with elderly relatives or those who have health problems in places that are experiencing outbreaks should consider wearing face masks at home, Birx said.
And those returning from summer vacations must be extra careful when they return, Birx said.
"If you have chosen to go on vacation into a hot spot, you really need to come back and protect those with comorbidities and assume you're infected," she said.
CNN's Naomi Thomas, Sharif Paget and Melissa Alonso contributed to this report.