Fear of the highly transmittable Delta coronavirus variant is causing every US state to report an increase in its average number of vaccinations.

The national rate of people receiving their first dose is up by more than 73 percent, and last week vaccination rates increased by more than 25 percent in adults and nearly 20 percent in ages 12-17, according to the Centers for Disease Control and Prevention (CDC) data.

The uptick pushed the national vaccination average to more than 637,000 doses administered each day — up by more than 24 percent in the last two weeks.

In a move to put pressure on more people to get vaccinated, New York City Mayor Bill de Blasio announced Tuesday that the city will require proof of at least one dose of a coronavirus vaccine for workers and customers for indoor dining, gyms, entertainment and performances, including Broadway, making New York the first US city to require proof. 

"If you're unvaccinated, unfortunately, you will not be able to participate in many things," de Blasio said. "If you want to participate in our society fully, you've got to get vaccinated."

People will be able to continue to dine outdoors without showing proof of vaccination. City officials plan to spend the next few weeks soliciting feedback on the policy before launching it on Aug 16 and starting to enforce it Sept 13.

About 66 percent of adults in the city are fully vaccinated, according to city data, and about 45 percent of New York City residents aren't yet fully vaccinated.

The seven-day average number of confirmed and probable daily coronavirus cases is now over 1,200 in New York City, according to figures this week. That figure was less than 250 at the start of July and peaked at more than 6,400 in early January, according to city statistics.

Tyson Foods, the biggest US meat supplier by sales, said it would require COVID-19 vaccinations for its US workforce of about 120,000 and would offer a $200 bonus to its front-line workers as an incentive. Meatpacking workers were among the hardest hit as infections began to spread in the US in spring 2020, with tens of thousands of plant workers infected and more than 130 deaths, according to labor union estimates.

Despite the increase in vaccinations, as of Friday nearly 40,000 patients with COVID-19 were in hospitals across the country, up nearly 190 percent in the last month.

The seven-day average of daily new coronavirus cases is up by more than 40 percent over the previous week, US Centers for Disease Control and Prevention Director Dr Rochelle Walensky said Monday. 

With vaccination rates rising but still below where they need to be to slow or stop the spread of the virus, according to health officials, many local leaders are turning back to masks to protect their populations.

Louisiana has restored its statewide indoor mask mandate as of Wednesday amid a surge in Delta-caused infections and hospitalizations that Democratic Governor John Bel Edwards calls the worst phase of the pandemic so far. It applies to all people age 5 and older at indoor public places regardless of vaccination status and will remain in place until at least Sept 1.

Louisiana has one of the lowest vaccination rates in the country. Forty-three percent of residents have had at least one dose of a vaccine, and 37 percent are fully inoculated. 

Dr Catherine O'Neal, who runs Our Lady of the Lake Hospital in Baton Rouge, Louisiana's largest hospital said, there were "no more beds left". She said COVID-19 hospitalizations had risen from 36 to 155 at the facility in two weeks.

But in Florida, Broward County public schools backtracked on their mask mandate Monday, saying the district would comply with the governor's executive order that prevents schools from requiring facial coverings. 

The move comes after Governor Ron DeSantis signed an executive order that would allow the state Board of Education to withhold funding to any district that compels students to wear masks when they return to school. DeSantis said he wants parents to be able to decide if  their children wear masks.

Florida is one of five states — along with Louisiana, Texas, California and Missouri —that make up nearly half of the new cases reported in the past week, according to data from Johns Hopkins University. In Florida, 86 percent of ICU beds are now occupied with COVID-19 patients, according to state health officials.