The week began with Florida’s high-flying governor, Ron DeSantis, in Texas, bashing Joe Biden over immigration at the southern border. But with the highly contagious Delta variant pushing new cases of Covid-19 in his home state to their highest level since January, DeSantis’s road trip was looking increasingly deaf in tone and timing.

By week’s end, Florida was accounting for almost a quarter of new infections nationally, with the US surgeon general, Vivek Murthy, warning of an “alarming” rise in deaths and hospitalizations.

“The challenge in Florida, and in far too many states, is [that] we still don’t have vaccination rates high enough, and in some pockets we have actually vaccination rates quite low,” Murthy said in an interview with McClatchy newspapers.

“The consequence is that Covid is now spreading very quickly in those populations.”

Meanwhile, DeSantis, who recently launched a line of campaign merchandise mocking masks and medical experts, was back home extolling the virtues of vaccinations.

“These vaccines are saving lives,” he said at a news conference at which he noted that more than 95% of new infections in Florida were of those who had not received a shot. The state ranks 25th in the US, with 48.1% of those eligible fully vaccinated, 0.7% below the national average.

Edwin Michael, professor of epidemiology at the University of South Florida, said: “The upsurge in cases and hospitalizations are due to fewer vaccinations, relaxation of social distancing measures, greater population mobility, plus the spread of more contagious variants.

“Until vaccination rates are ramped up to achieve herd immunity over this fall, people will still need to follow social distancing measures, such as wearing face coverings at the very least, to protect themselves and to reduce infection spread.”

Michael said Florida’s current vaccination rate must double to prevent the resurgent virus getting out of control.

Florida’s nation-leading surge, which according to the Centers for Disease Control and Prevention (CDC) has seen the seven-day average of cases more than quadruple from 1,839 on 1 July to 8,911 three weeks later, is filling up hospitals around the state.

Hospital systems in Miami, Jacksonville, Tampa Bay and central Florida are reporting a record rise in admissions, and are limiting visitors and warning of looming staff shortages.

“We encourage everyone who’s eligible to get vaccinated as soon as possible. We want to avoid a repeat of last year and overwhelming our hospitals,” Carlos Migoya, chief executive of Miami’s Jackson Health, said.

DeSantis has promised action: but only to convene a special session of the Florida legislature to block any move by the Biden administration to implement a mask mandate in the state’s public schools.

“If I were a parent in Florida, that would be greatly concerning to me,” the White House press secretary, Jen Psaki, told reporters after DeSantis announced the proposal.

“Kids under 12 are not vaccinated, they’re not eligible yet. That puts kids at risk. It’s not aligned to public health standards.”

Physicians have welcomed DeSantis’s calls for more residents to get vaccinated, but their frustration has grown at what they see as mixed messaging, including his attacks on federal health officials – “quote-unquote experts”, in the governor’s words – who have criticized those skeptical of the vaccines.

Already this year DeSantis has issued a blanket pardon to anyone convicted of breaching local authority Covid mandates, and promised to use power handed to him by Florida’s Republican-dominated legislature to invalidate local emergency measures.

He has also sued the CDC, with mixed success, to try to prevent cruise lines from being able to require passengers to be vaccinated or comply with other health requirements. And in recent days DeSantis has stepped up his personal animosity towards Dr Anthony Fauci, the government’s leading infectious diseases expert. As well as fundraising off the “Don’t Fauci my Florida” beer koozies and T-shirts, DeSantis accused Fauci of attempting to “muzzle” his three-year-old son with a mask mandate.

“For weeks cases have been rapidly increasing so it’s curious to me as a physician when Governor DeSantis gave a speech basically poking fun at Dr Fauci,” Bernard Ashby, a Miami-based cardiologist and head of the Florida chapter of the Committee to Protect Health Care, said.

“While DeSantis is traveling around bragging about Florida’s handling of the pandemic, or lack of, and making fun of Fauci, doctors here are feeling like we are back at square one.”

Political opponents have also been critical. Debbie Wasserman Schultz, a US congresswoman for Florida and former chair of the Democratic National Committee, told CNN: “When you’ve passed a law through the state legislature to say businesses can’t require vaccinations, that local governments can’t take steps to keep their own people safe, that ignores public health, who really through the whole pandemic did everything he could to stiff-arm the pandemic and taking care of people, when we’re now facing the largest rise in the country, then the responsibility lies with you.”

Brice Barnes, a Florida Democratic strategist and co-founder of the political action group Ron Be Gone, said DeSantis appeared increasingly fixated on his widely expected run at the White House.

“It’s very clear that Ron DeSantis’s priorities are what’s in his best political interests, which is launching his presidential campaign for 2024. He seems to be focused on everything but Florida,” she said.

“We’re seeing governors from other states look at the situation pretty seriously and start to shift their policies as cases ramp up, and DeSantis needs to have an open mindset and not be playing politics with a public safety crisis.”

DeSantis’s media representatives did not respond to a request for comment.