With the novel coronavirus surging among the San Diego State student body, the university announced a “pause” of in-person classes Wednesday after public health officials said 64 cases have now been confirmed and approximately 100 more, mostly living off campus, are now under quarantine.

The news, which came just nine days after the start of SDSU’s fall semester on Aug. 24, was a significant setback for a university that brought 7,997 of its 35,485 enrolled students back to campus to participate in roughly 200 different courses — mostly labs — deemed difficult to teach through distance-learning platforms.

Luke Wood, the university’s vice president of student affairs and chief diversity officer, said all in-person courses — a total of 627 classes — will be taught online for the next four weeks, during which the university will assess the spread of the virus among students, faculty and staff.

The pause was not confined to classes. The university also announced a two-week pause for on-campus practices and workouts for student athletes.

Given that attending at least one in-person class was the main reason why the students came to campus, Wood acknowledged Wednesday afternoon that some, including the 2,600 now living in campus housing, may see no further reason to stay.

But heading home, he added, will come with its own requirements for anyone who wishes to return if and when the current pause period ends.

“If any student chooses to leave their on-campus house, they will be permitted to do so; however, if they return at a later time, they will be required to quarantine for a 14-day period,” Wood said.

It is a somewhat more nuanced approach than has been recently seen at universities struggling to navigate in-person education in the midst of a pandemic. Chico State, for example, took a more drastic approach this week, halting all in-person classes after 36 students and staffers tested positive, clearing its dorms and sending learners home.

It was not clear whether such a step might be necessary at SDSU. Dr. Eric McDonald, medical director of the county’s epidemiology unit, said that his office has worked daily with university case investigators to quickly confirm infections through testing, identify those in close contact with those who have tested positive, and order quarantines for those exposed.

But it was clear over the weekend that many recently returned students mingled, often without wearing masks or keeping 6 feet of distance, in the neighborhoods surrounding campus. It is a bit too early to tell, McDonald said, whether the virus is spreading at something like an exponential rate or whether containment efforts undertaken so far have managed to break chains of person-to-person transmission.

While the physician said there are not yet enough cases to say how quickly the case rate associated with SDSU is doubling, it is certain that more infections will be detected.

“We expect the numbers to go up; this is a serious situation,” McDonald said. “I have no doubt, frankly, that this will go into triple digits.”

And concerns go far beyond SDSU.

All cases among students are added to the county’s overall coronavirus totals, which determine the local case and per-capita rates used to determine where San Diego County sits in the state’s new four-tier reopening blueprint. If the number of daily cases per 100,000 residents climbs beyond seven, or the percentage of positive coronavirus tests exceeds 8 percent, San Diego would fall to the lowest tier and local businesses, churches and other organizations would lose some of the indoor operating capacities they only just regained.

Three additional outbreaks, 250 cases and seven deaths were included in the county’s daily COVID tracking report Wednesday. Outbreaks occurred at two restaurants with bars and one residence, which a county official who declined to be named said was an SDSU dorm.

The university did not respond Wednesday afternoon to requests for confirmation of the outbreak, although an official did say Monday that cases have occurred at the Zapotec, Villa Alvarado Apartments and South Campus Plaza North, all part of SDSU’s dorm system.

Wednesday afternoon, Kaitlyn Infanger, a freshman living in South Campus Plaza North, was taking the current situation day by day.

“It’s definitely scary but as long as my roommate and I are careful, I think it’s going to be OK,” Infanger said.

The 18-year-old from Los Angeles said that COVID restrictions have made it difficult to meet other students and get the full college experience. She said she may go home if cases continue to increase because all her classes are online.

It was clear that total separation is hard to pull off among young people out on their own, many for the first time.

A group of students sitting outside South Campus Plaza wore face masks but occasionally pulled them down to their chins to talk or take sips of their coffee.

Jaden, 18, who provided only his last name, walked out of the dorm on College Avenue and said most people are trying to do their best to stay safe.

He said he is worried that cases are increasing, especially because he knows there are reports of positive tests coming back among the residents of his building. He walked out of his dorm wearing two face masks for extra protection.

“It’s a little scary,” he said. “I’m thinking of going back home because it’s kind of picking up a bit.”

Most students on campus Wednesday afternoon wore face masks and tried to practice social distancing. Some students studied and watched online lectures inside the Lee and Frank Goldberg Courtyard in the student union. Tables were positioned at least 6 feet apart and most tables had only one chair to keep students from sitting in groups.

Danielle Washington, 19, lives at M@College Apartments, where one positive COVID-19 case was reported earlier this week. She said she’s not concerned about getting sick because people who test positive must quarantine in their own apartment units.

“I’m not too worried about it,” Washington said.

It was clear last weekend that many share that opinion.

The San Diego Union-Tribune observed about 200 students, mostly in groups, walking without masks on campus and in adjacent neighborhoods between 11:30 p.m. Friday, Aug. 28, and 2 a.m. Saturday, Aug. 29.

In response, the university hired Elite Security, a private security firm, to patrol neighborhoods, collect information on health order violations, and report the information to the university for further action.

Wood said Wednesday that his office has followed up on those cases.

“We have been issuing warnings, notices and investigations to organizations and individuals,” Wood said, although he did not provide any numbers.

The university also clarified statements made by one of its representatives during the question-and-answer period of the county’s twice-weekly COVID briefing during which the SDSU cases were widely discussed.

Although an official indicated that all 64 cases mentioned by McDonald were in addition to the 45 already listed on the university’s website, an official later said that 20 of the 64 were among those already listed.