The coronavirus has killed more than 73,000 people in the United States, according to Johns Hopkins University and has crushed the economy.
Many governors are starting to reopen their states, despite the potential dangers it may cause down the road.

President Donald Trump is calling the coronavirus one of the greatest threats the U.S. has ever seen.

"This is worse than Pearl Harbor. This is worse than the World Trade Center. There's never been an attack like this," says President Trump.

Despite that warning, more than 40 states, will be at least partly reopened by this weekend.

"I am concerned. We'll know in the next three to four weeks, now, whether or not we'll have more of a surge than what we have now. But we're treating the virus in large part as if it's yesterday's news," says Houston Mayor Sylvester Turner.

Over the past two weeks, 19 states saw an overall increase in reported coronavirus cases, 13 saw them drop while 18 held steady, according to Johns Hopkins University data.

"For states that are looking to reopen, I think it's important to lead with public health risk assessments, and so we have suggested it should be low-risk activities that are the first to be re-introduced into the community. Things that are outside are a great place to start," says Caitlin Rivers, Senior Scholar at Johns Hopkins University.

Experts say only time will tell if the reopening process will cause the virus to spread.

However, health officials say the threat isn't going away anytime soon.

"We're just at the beginning of this pandemic and must focus on the future. There's only one enemy here-a dangerous microbe. It's us against them: humans against the virus," says Dr. Tom Frieden/Pres. and CEO, Resolve to Save Lives.

Although President Trump recently said there's a chance a vaccine could be ready before the end of the year, others, including infectious disease expert Dr. Anthony Fauci, says 2021 is more likely.

 MORE: LIVE BLOG - Coronavirus updates from the tri-state area and beyond