ST. PETERSBURG, FLA. -- As Florida enters the height of summer tourist season, the state's largest cities and counties are closing beaches, mandating masks and halting business reopenings, hoping the measures will slow a steep resurgence of coronavirus cases.

Many of the new cases are among younger adults and attributed to relaxed socializing in bars and at parties. When these patients wind up in hospital beds, their conditions are less acute than those of people infected during the deadliest phase of the state's outbreak.

Still, there are concerns that older and more vulnerable people will be exposed as Florida seeks a jump re-start of its economy with theme park reopenings, major sports events and the Republican presidential nomination celebration.

In every crowd, there will be asymptomatic people, many of them refusing to wear masks and seeding the infections that will prompt more severe illnesses in the weeks ahead, experts say.

"Any time you have these reopenings, you're depending on people do to the right things, to follow the rules. I think that's where the weak spots come in," said Dr. Cindy Prins, an epidemiologist and medical professor at the University of Florida.

She warned that things are likely to get worse before they get better.

"Unfortunately we're a couple of weeks late to the game of really being able to get this under control," said Prins.

New confirmed cases have spiked significantly over the past week. The Florida Department of Health reported on Tuesday more than 6,012 new confirmed cases of COVID-19. More than 8,000 new cases were tallied each of three days late last week. In total, the state now has more than 152,434 confirmed coronavirus cases and more than 3,500 deaths.

Air conditioning could be a factor among states across the South were new cases have been spiking. Air conditioned areas where the virus can re-circulate can pose greater health risks than places where fresh air is brought in from outside, said Dr. Kristin Englund, an infectious disease physician at Cleveland Clinic.

"I definitely think the air conditioning and the oppressive heat in the South are going to play a role in this," said Englund. "Typically we see respiratory viruses worsen in the winter time because people are more enclosed. It's cold inside so people are more inside their houses where they're in close contact with people."

The big spike in Florida's confirmed new cases so far hasn't translated into a deluge of critical hospitalizations statewide. State and hospital officials say these cases are milder on average and also include people in hospital for other reasons who test positive in routine scanning.

Still, hospital intensive care units are starting to fill up in worst-hit South Florida. Miami-Dade County has about 23 per cent availability in ICU beds, though a facility in Homestead has seen its 16 ICU beds fill up and one of the biggest in Miami, Baptist Hospital, has only 6 of its 82 ICU beds available, according Florida's Agency for Health Care Administration.

Health officials say the next several weeks will be critical to Florida's success, or failure. The Fourth of July, the reopening of Disney, and the Republican National Convention all loom on the calendar with a promise of crowds.

Republicans and Trump moved the convention's nomination portion to Jacksonville after North Carolina Gov. Roy Cooper refused to guarantee the event could be held in Charlotte without public health restrictions. Now, Florida Republicans are saying that they will institute safety precautions for the event -- including branded masks.

"I think we can do it in a way where you can follow the social guidelines that are in place but still have a successful event," said state Sen. Joe Gruters, the party chairman. "I will tell you that the Republican Party of Florida will be providing masks for our entire delegation. I'm choosing a design and we're going to have a special gift for all the members of the delegation that attend with us."

Central Florida's theme parks are another concern. Universal has been open for weeks. Disney is scheduled to open July 11, and says masks will be required for guests.

Thousands of Walt Disney World workers started heading back to work this week ahead of the Magic Kingdom's reopening. The resort has been closed since mid-March.

Krysta White, who works in the Animal Kingdom park, said she feels safer at Disney World than the grocery store, because of all the protocols implemented.

"I'm still nervous, but I feel they've done everything to make it as safe as possible," White said on a union Facebook video discussion.


AP reporters Mike Schneider in Orlando, Kelli Kennedy in Fort Lauderdale, and Brendan Farrington in Tallahassee contributed to this report.