NEW YORK (NewsNation Now) — Some hospitals across the country are overwhelmed by the new delta variant, particularly in the Midwest, where many areas are seeing a rise in COVID-19 cases.

The rise coincides with low vaccination rates.

In Missouri, hospitals are bringing in more ventilators and staff, as a COVID-19 overflow ward was recently closed.

Doctors and nurses are tired, frustrated, and struggling to keep up. The surge is coming on stronger and faster, and the patients are younger.

“The World Health Organization — I loved one of their quotes — and that is this version is the fastest and the fittest,” said Dr. Dale Bratzler, Chief Covid Officer at the University of Oklahoma.

“It’s a wake-up call,” said Dr. George Monks, the past president at the Oklahoma State Medical Association. “It’s a red flag for people in Oklahoma.”

The number of delta variant cases is on the rise and threatening unvaccinated people.

It’s about one in four new cases in New York, and one in five in Ohio.

“We know that it’s similar and that it’s more transmissible,” said Dr. Daniel Rhoades from the Cleveland Clinic.

On Friday, medical experts pushed back on comments from Missouri’s Republican governor.

“The state has a stockpile of ventilators sitting over there, so when somebody says we’re out of ventilators that’s more of a management problem than anything,” Gov. Mike Parson said Thursday.

“And really it’s a wake-up call… it’s a red flag for people in Oklahoma,” said Dr. George Monks, the former president of the Oklahoma State Medical Association.

Steve Edwards, the CEO of a major health care system, tweeted a response saying, “Mercy running out of ventilators is not a management issue. It’s about how rapidly the landscape changes under the delta variant.”

“These are states and places where there is low immunity and the delta variant is definitely more transmissible,” said Dr. Monica Gandhi, an Infectious Disease Specialist at the University of California San Francisco.

Infectious disease experts across the country are watching and say the cause of the spike is all too clear.

“The vaccines work for this,” Dr. Lakshman Swamy, an ICU Physician in Boston. “Vaccines work against Delta I have all of our data supports that and what we’re seeing is that people who are vaccinated are protected.”