COVID-19 cases have tripled in the U.S. over the last two weeks.

Across the U.S., the seven-day rolling average for daily new cases in the U.S. rose over the past two weeks to more than 37,000 on Tuesday, up from less than 13,700 on July 6, according to Johns Hopkins University. Health officials, according to the Associated Press, are blaming the delta variant and slowing vaccination rates.

Just 56.2% of Americans have gotten at least one dose of the vaccine, according to the Atlanta-based Centers for Disease Control and Prevention.

The latest Johns Hopkins COVID numbers show the U.S. continues to lead the world in both cases — 34.1 million — and deaths, with more than 609,680.

On Tuesday, Senate Republican leader Mitch McConnell implored unvaccinated Americans to take the COVID-19 shot, issuing a stark and grave warning of a repeat of last year’s rising caseloads and shutdowns if people refuse to protect themselves from the coronavirus.

McConnell urged Americans to ignore the “demonstrably bad advice” coming from pundits and others against the vaccines. As cases skyrocket, he noted nearly all the new virus hospitalizations in the U.S. are among people who have not been vaccinated.

“If there is anybody out there willing to listen: Get vaccinated,” McConnell said at his weekly press conference at the Capitol.

“These shots need to get in everybody’s arms as rapidly as possible or we’re going to be back in a situation in the fall that we don’t yearn for — that we went through last year,” he said. “This is not complicated.”

McConnell has been one of the most outspoken members of his party in urging vaccinations to stop the virus spread, speaking often in his home state of Kentucky of the need for people to get the shot.

On Wednesday, public health officials revealed U.S. life expectancy fell by a year and a half in 2020, the largest one-year decline since World War II. The drop spelled out by the CDC is due mainly to the COVID-19 pandemic, which health officials said is responsible for close to 74% of the overall life expectancy decline.

More than 3.3 million Americans died last year, far more than any other year in U.S. history, with COVID-19 accounting for about 11% of those deaths.

In New York City, workers in city-run hospitals and health clinics will be required to get vaccinated or get tested weekly as officials battle a rise in COVID-19 cases, Mayor Bill de Blasio said Wednesday.

De Blasio’s order will not apply to teachers, police officers and other city employees, but it’s part of the city’s intense focus on vaccinations amid an increase in delta variant infections.

The number of vaccine doses being given out daily in the city has dropped to less than 18,000, down from a peak of more than 100,000 in early April. About 65% of all adults are fully vaccinated, but the inoculation rate is around 25% among Black adults under age 45. About 45% of the workforce in the city’s public hospital system is Black.

Meanwhile, caseloads have been rising in the city for weeks, and health officials say the variant makes up about seven in 10 cases they sequence.

“We need our health care workers to be vaccinated, and it’s getting dangerous with the delta variant,” de Blasio told CNN.

In Louisiana, health officials reported 5,388 new COVID-19 cases Wednesday and said it’s the third-highest daily count since the beginning of the pandemic in early 2020. Hospitalizations for the disease rose to 844 statewide, up more than 600 since mid-June.

In New Orleans, officials weighed a possible revival of at least some of the mitigation efforts that had been eased as the disease was waning.

Mayor LaToya Cantrell and the city’s top health official, Dr. Jennifer Avegno, were expected to make an announcement later Wednesday. On Tuesday, Cantrell spokesman Beau Tidwell said “all options are on the table.”

The Associated Press contributed to this report.