The number of Covid patients in Florida hospitals has risen to a new high, breaking records set during previous waves before vaccines were available.
US health officials say 11,515 Florida residents are currently in hospital. Many are younger and healthier than patients seen earlier in the pandemic.
On Saturday, Florida set a record for most new infections in a single day.
Republican Governor Ron DeSantis opposes efforts to make vaccines or masks mandatory.
Across the US, one in three new cases last week were recorded in Florida or Texas.
Hospital beds in Florida are quickly filling up. Some have already reached capacity, with patients placed in hallways, lobby waiting areas and makeshift overflow centres.
"We have more Covid patients in our hospital with this surge than we did with the original surge," one hospital official in Tallahassee, Dr Dean Watson, told NBC News.
"We have been living Covid for over a year and a half. The stress and the strain for all the providers and nursing staff is really getting to everyone."
It comes as vaccine rates, which have slowed since the spring, have begun to tick up again as the highly contagious Delta variant sweeps the country.
Over 70% of Americans have now received at least one vaccine jab, a milestone that President Joe Biden had hoped to hit by the 4 July Independence Day holiday.
The vaccination rate in Florida roughly mirrors the national average, but is below the rates seen in many north-eastern states.
About 50% of residents have been fully vaccinated, but the number is far higher among the state's large pensioner community.
Officials say the vaccinated are unlikely to experience symptoms if they catch the coronavirus, although they can still spread it.
The unvaccinated account for nearly all cases of sickness and death, say officials who are now referring to Covid as a "pandemic of the unvaccinated".
Florida has recorded over 39,000 deaths since the coronavirus pandemic began, according to Johns Hopkins University.
Many regions and businesses across the US are once again introducing rules to force people to wear masks in public places.
Gov DeSantis, who is rumoured to be considering a presidential run in 2024, has worked with state Republicans to block local governments and schools from requiring vaccinations or masks.
Elsewhere in the US, New York City is planning to issue a vaccine requirement for indoor activities, a policy considered to be the first of its kind in the US.