St. Louis' top health official talked with ABC News Monday about Missouri's rising coronavirus cases and gave a stark warning to the rest of the country.

“The delta variant is a whole new virus," Dr. Sam Page, the county executive for St. Louis County, Missouri, told ABC News.

Since June, Missouri’s daily case average has surged by 500%, with the state now reporting its highest number of new infections since mid-January. Hospital admissions have more than doubled in recent weeks. They are up by 125% in the last month, according to Page.

At the same time, vaccinations have seen a slight increase the county, Page said. However, he reiterated that it will be at least another month before the county sees full effect of the vaccines in those patients.

“We just wish that we could get people vaccinated sooner because the illness has an unfortunate loss of life associated with it. And that's just a terrible thing to watch,” Page said.

Page said there was no “silver bullet” that will help increase vaccination rates across the state, or drive down cases immediately, but said that officials must work together fast.

“It's going to be multifactorial, a lot of education, a lot of time, a lot of comforting,” he said.

-ABC News' Cheyenne Haslett and Arielle Mitropoulos

The Centers for Disease Control and Prevention is now categorizing the U.S. as having "high" community transmission, with nearly 62% of counties in the nation reporting high (43.79%) or substantial (18.17%) transmission.

New York County, which includes Manhattan, is among those now reporting substantial community transmission.

One month ago, only 8% of counties were reporting high transmission.

Louisiana, Florida, and Arkansas have the country's highest case rate with over 300 new cases per 100,000 residents.

Missouri follows closely behind with 200 new cases per 100,000 residents.

Hospitalization numbers are also rising. More than 27,300 COVID-10 patients are in hospitals across the country -- a 36.8% jump in the last week.

-ABC News’ Arielle Mitropoulos

Department of Veterans Affairs Secretary Denis McDonough announced Monday that COVID-19 vaccines will be mandatory for the department’s health care personnel.

Four VA employees, all of whom were unvaccinated, died in recent weeks, the department said. At least three of those cases were linked to the delta variant.

VA employees will have eight weeks to be fully vaccinated.

McDonough said this mandate is "the best way to keep Veterans safe, especially as the Delta variant spreads across the country."

-ABC News’ Cindy Smith

All unvaccinated New York City municipal workers will have to get weekly testing by the start of school in September, according to Mayor Bill de Blasio's office.

The new requirement will apply to all city workers, including police officers, firefighters and teachers. The new rule will go into effect on Sept. 13, when students are expected to return to public schools.

The New York Police Department has a 43% vaccination rate while about 55% of New York City Fire Department employees are vaccinated.

Workers in publicly run residential or congregate care facilities, like nursing homes, must present proof of vaccination even earlier, on Aug. 16.

California Gov. Gavin Newsom announced a similar mandate on Monday. Beginning on Aug. 9, state employees and health care workers must show proof of vaccination or get tested regularly.

In California, 75% of those eligible have received at least one dose.

"Everyone that can get vaccinated—should," Newsom tweeted.

-ABC News’ Aaron Katersky