By Anurag Maan and Gabriella Borter

Nov 19 (Reuters) - The number of people hospitalized with COVID-19 in the United States has jumped nearly 50% in the last 14 days, straining the nation's healthcare system and forcing states to impose new restrictions to curb the alarming spread of the coronavirus.

Nearly 79,000 people in the United States were hospitalized with the virus on Thursday, a Reuters tally shows, the most at any time during the pandemic, following sharp rises in infection rates around the country and particularly the Midwest.

New social restrictions aimed at slowing community spread and lowering the infection rate were taking effect this week, including the abrupt closing of New York City's public schools on Thursday as the city's 7-day positive test rate average hit 3%. Restaurants, bars, fitness centers and entertainment venues in Minnesota were ordered closed starting on Friday through at least Dec. 18.

New York City Mayor Bill de Blasio defended his decision to shut down the nation's largest school district, noting that additional safety standards to reopen schools would be announced before Thanksgiving after consultation with Governor Andrew Cuomo.

"Our schools are going to come back, but they're going to come back with additional safety standards," de Blasio told CBS on Thursday.

Suzanna Riordan, a Brooklyn mother, said she burst into tears upon learning that her 7-year-old daughter would be denied in-school learning until at least after the Thanksgiving holiday weekend. Her daughter Olivia had been excited at the prospect of adding one more day of in-person education a week starting next week, Riordan said. But the excitement quickly turned into disappointment.

"Since September she's gotten maybe seven days in school," Riordan told Reuters. "And those are the days where...she comes home excited and happy and she gets to see other second graders. And that's gone again."

Governor Tim Walz of Minnesota, one of several Midwest states dogged by the country's highest infection rates per capita, said his shutdown order was necessary as more than 90% of hospital intensive care unit (ICU) beds were already occupied in the eastern half of the state.

In nearby Wisconsin, 90.2% of ICU beds were occupied on Thursday, state data showed.

Health and government officials have warned that the dramatic rise in hospitalizations over the last couple of weeks may only get worse heading into winter, and urged Americans to limit their Thanksgiving holiday celebrations next week to small, single household gatherings.

The U.S. northeast region, which for months had successfully held the virus at bay after the crushing first wave in the spring, has seen the highest percentage jump in hospitalizations at 85.4% over the past 14 days, according to Reuters data. During that same period, hospitalizations in the Midwest have increased by 56.8%, in the West by 50.1%, and in the South by 34.4%.

Kansas, where the positive test rate was approaching 60% last week, became the latest state to issue a statewide mask mandate on Wednesday.

The Trump administration has persisted in criticizing state efforts to curb the virus by shutting down parts of the economy, while refusing to pass on critical COVID-19 data to President-elect Joe Biden and his transition team.

White House Press Secretary Kayleigh McEnany praised the Republican governors of Texas and Florida on Twitter on Thursday for upholding "freedom" by not imposing business shutdowns as public health measures in their states - in some cases overriding the wishes of local officials.

The growing tide of infections and public health-recommended shutdowns portends a bleak winter for the American economy.

Last week, the number of Americans filing new claims for jobless benefits unexpectedly rose as new business closures to control skyrocketing COVID-19 infections unleashed a fresh wave of layoffs and further slowed the labor market recovery.

Initial claims for state unemployment benefits totaled a seasonally adjusted 742,000 for the week ended Nov. 14, compared to 711,000 in the prior week, the Labor Department said on Thursday. Economists polled by Reuters had forecast 707,000 applications in the latest week.

(Reporting by Anurag Maan and Gabriella Borter; Additional reporting by Maria Caspani and Susan Heavey; Writing by Gabriella Borter; Editing by Bill Berkrot)