By Brendan O’Brien and Maria Caspani

CHICAGO (Reuters) – Chicago issued a stay-at-home advisory and Detroit stopped in-person schooling on Thursday to staunch the coronavirus outbreak as more than a dozen states reported a doubling of new COVID-19 cases in the last two weeks.

Officials in the Midwestern cities along with New York, California, Iowa and other states were re-imposing this week restrictions that had been eased in recent months. The moves were driven by surging infection rates and concern that the onset of winter, when people are more likely to gather indoors, will worsen the trends.

Chicago Mayor Lori Lightfoot on Thursday issued a 30-day advisory calling upon residents to stay at home and have no visitors, even during Thanksgiving festivities. The third- largest city in the United States could see 1,000 more COVID-19 deaths by the end of 2020 if residents do not change behaviors to stop the spread of the virus, Lightfoot said.

Lightfoot set a 10-person limit on gatherings, including indoor and outdoor events, and said travelers from out of the state needed to quarantine for 14 days or submit a negative coronavirus test.

“None of us can keep maintaining the status quo in the face of this very stark reality,” the mayor told reporters, noting the average number of cases have gone from 500 to 1,900 per day over the last month and the city’s positivity rate shot up to 15% from 5%.

Illinois has emerged as the pandemic’s new epicenter in the region as well as across the country. In the past two weeks, the state reported about 130,000 cases, the highest in the country and more than hard-hit Texas and California.

A Reuters tally showed coronavirus cases more than doubling in 13 states in the past two weeks.

In Michigan, the Detroit public school system – the state’s largest – said on Thursday it would suspend of in-person education until Jan. 11, with the infection rate in the city rising rapidly. The district will hold all classes online starting Monday.

New York City Mayor Bill de Blasio said on Thursday that the country’s largest school system was preparing for a possible shutdown but closure might still be averted.

“We’re not there yet, and let’s pray we don’t get there,” de Blasio told reporters. De Blasio has said schools will close if the percentage of city residents testing positive, now at a seven-day average of 2.6%, surpasses 3%.

Total COVID-19 cases across the United States hit an all-time daily high for a second day in a row on Wednesday at 142,279 and crossed the 100,000 mark for an eighth consecutive day, Reuters data showed.

The number of people hospitalized with the virus surged to at least 64,939 by late Wednesday, the highest ever for a single day during the pandemic, increasing by more than 41% in the past two weeks. The death toll rose by 1,464 to a total of 241,809.

Vaccine developers have offered some good news this week, with Pfizer and BioNTech trumpeting successful early data from a large-scale clinical trial of a coronavirus vaccine.

Health experts are hopeful that a vaccine might become available in the coming months for the most vulnerable populations and for healthcare providers.

But with a more lengthy timeline for the general public, many are urging strict adherence to well-known virus mitigation measures like wearing a face covering, washing hands and maintaining a safe social distance.

“We hope that by the time you get into the second quarter, end of April, early May, May-June – somewhere around that time, the ordinary citizen should be able to get it,” Dr. Anthony Fauci, a top U.S. health official, told the ABC “Good Morning America” program on Thursday.

“What we need to do is what we’ve been talking about for some time now but really doubling down on it.”

(Reporting by Maria Caspani in New York and Anurag Maan in Bengaluru and Brendan O’Brien in Chicago, additional reporting by Peter Szekely in New York and Doina Chiacu in Washington; Editing by Howard Goller and Cynthia Osterman)