COVID-19 deaths and cases in the US have climbed back to levels not seen since last northern winter, erasing months of progress and potentially bolstering President Joe Biden’s argument for his sweeping new vaccination requirements.

The cases – driven by the Delta variant combined with resistance among some Americans to getting the vaccine – are concentrated mostly in the south.

While one-time hot spots like Florida and Louisiana are improving, infection rates are soaring in Kentucky, Georgia and Tennessee, fuelled by children back in school, loose mask restrictions and low vaccination levels.

The dire situation in some hospitals is starting to sound like January’s infection peak: Surgeries cancelled in hospitals in Washington state and Utah. Severe staff shortages in Kentucky and Alabama. A lack of beds in Tennessee. Intensive care units at or over capacity in Texas.

The deteriorating picture nine months into the nation’s vaccination drive has angered and frustrated medical professionals, who see the heartbreak as preventable. The vast majority of the dead and the hospitalised have been unvaccinated, in what has proved to be a hard lesson for some families.

“The problem now is we have been trying to educate based on science, but I think most of the education that is happening now is based on tragedy, personal tragedy,” said Dr Ryan Stanton, an emergency room physician in Lexington, Kentucky.

The US is averaging more than 1800 deaths and 170,000 new cases every day, the highest levels respectively since early March and late January. Both figures have been on the rise for the past two weeks.

The country is still well below the terrifying peaks reached in January, when it averaged about 3400 deaths and 250,000 cases a day.

The US is dispensing about 900,000 vaccinations a day, down from a high of 3.4 million in mid-April. On Friday (local time), a Food and Drug Administration advisory panel will meet to discuss whether the US should begin giving booster shots of the Pfizer vaccine.

On a positive note, the number of people in hospital with COVID-19 appears to be levelling off or even declining at about 90,000, or about where things stood in February.

Last week, Mr Biden ordered all employers with more than 100 workers to require vaccinations or weekly tests, a measure affecting about 80 million Americans.

But measures aimed at containing the virus have run into opposition. Last week, a Tennessee high school student who spoke at a school board meeting in favour of a mask mandate was heckled by adults while he talked about his grandmother dying from the virus.

The biggest surge over the summer occurred in states that had low vaccination rates, particularly in the south, where many people rely on air-conditioning and breathe recirculated air.

States further north could have upticks as the onset of cold weather sends people indoors.