(NewsNation) — A spike in COVID-19 cases in China comes with a warning for the U.S. as cases — especially in the Northeast — are on the rise, according to the Centers for Disease Control and Prevention.

Colleges and universities across the country are reinstating mask mandates and switching to online classes in response to the uptick.

Colleges in Washington, D.C., New York, Pennsylvania, Massachusetts, Connecticut and Texas have reimposed a range of virus measures, with Howard University moving to remote learning amid a surge in cases in the nation’s capital.

In the third year of COVID-19 disruptions on U.S. college campuses, some students tell NewsNation they would like university officials to take restrictions even further.

“When, like, sickness is so rampant right now — so many people I know are getting sick — to only have a mandate for the classrooms seems a little backwards to me,” Columbia University student Gabrielle Pereira said.

One of the counties identified by the CDC as having a high spread rate is home to New York’s Syracuse University, which announced last week that it would again require masks in classrooms.

The University of Rochester in upstate New York, the University of Connecticut, Bowdoin College in Brunswick, Maine, and Columbia University in New York City took a similar approach. Many, like Columbia, noted that their surveillance testing programs were finding more cases.

Philadelphia ended its indoor mask mandate last week, abruptly reversing course just days after city residents had to start wearing masks again amid a sharp increase in infections.

Starting Monday, the University of Pennsylvania and Temple University are requiring them again.

In Washington, D.C., Howard University was largely quiet this week, with many students taking classes and exams from home. The academic year is coming to a muted end as rising virus numbers prompted administrators to abruptly shift back to online education.

The city’s infection rate has more than doubled in April. American, Georgetown and George Washington University also reinstated their indoor mask mandates. But Howard is the only one that has moved away from in-person instruction.

The rise in COVID-19 cases is affecting global markets.

U.S. stocks are following global markets lower, especially in China, over worries that strict lockdown measures there might crimp the world’s second-largest economy and potentially hurt global economic growth. 

“Stock markets across Asia suffered a big sell-off. I think this is the start of a big sell-off. It is by no means the end,” said Francis Lun, chief executive officer of Geo Securities Limited.

In Beijing, there are long lines for COVID-19 testing.

There are also long lines for food as residents worry about strict lockdown as seen in Shanghai.

A video circulating on social media appears to show people not just locked down in Shanghai, but fenced-in — and breaking through erected COVID-19 barricades.

Experts in the U.S. have issued warnings about the shortcomings of China’s so-called ‘Zero-Covid’ policy.

“We saw from Hong Kong, unfortunately, that we had a lot of deaths recently with ba.2.. And now I’m very fearful for China,” said Dr. Monica Gandhi, infectious disease expert at the University of California, San Francisco.

Beijing will expand its mass COVID-19 testing campaign to an additional 10 districts and one economic development area, an official for the Chinese capital said late Monday.

The Associated Press and Reuters contributed to this report.