A coronavirus outbreak among 45 people at the University of Southern California has been tied to three fraternities, Los Angeles County’s top health official announced Wednesday.

The outbreak is the largest among colleges and universities in the county, Public Health Director Dr. Barbara Ferrer said.

A group of graduate students at USC, some of whom live together, also became infected after socializing.

Additionally, a separate outbreak is being investigated at UCLA after “a number” of football players returned to campus and tested positive, Ferrer said. She did not provide additional details about either of the outbreaks.

Ferrer highlighted the hotspots before announcing the county’s preliminary protocols for reopening higher education settings, which she noted will not happen anytime soon.

“I know that so many students and teachers and staff are eager to return to their campuses, but it simply won’t be possible to return to collegiate life as we knew it before. Dorms, classrooms and social life that’s offered by our colleges and universities create high-risk, activities and become high-risk settings for the spread of COVID-19,” Ferrer said. “Given that this virus has reached every single part of the country, and will be an unwelcome visitor hitching a ride with students as they return to our campuses, we need to be very vigilant in how we reopen.”

Ferrer said the county will follow any guidelines released by the state regarding the reopening of colleges and universities, but indicated that local officials are planning for the safe return of students and faculty.

“The common thread is that colleges and universities, like all other workplaces and places in our community, will have to step up their infection control practices, including the regular sanitizing of common spaces, consistent use of face coverings in all parts of the campus, and the reconfiguration of campus spaces, including dorms, to enable appropriate physical distancing,” Ferrer said.

Infections and community spread among younger people remains a concern in Los Angeles County, especially since that age group is more likely to want to gather with people outside their household, Ferrer said.

Nearly 60% of the 2,347 new COVID-19 cases reported Wednesday were in residents between 18 and 49 years old.

This week, officials effectively banned gatherings following a fatal shooting at a massive party at a Beverly Crest home.

“Gatherings of people from different households are such a bad idea at this point in time, particularly when this is happening as many have expanded the number of their contacts with others because they are back at work, or they are going out shopping, and they’re eating out,” the director said.

Infections among younger people have increased dramatically during the summer months, Ferrer noted.

Since the beginning of June, for example, case rates of people between 30 and 48 are the highest among all age groups in the county.

Additionally, case rates among people between 18 to 29 quadrupled from the beginning of June the end of July.

“This explosive growth in cases shows that these two age groups continue to drive new infections,” Ferrer said.

And while hospitalizations and deaths are trending down for every age group in the county, that doesn’t mean younger people aren’t at risk.

“No matter how young you are, you are at risk for death from COVID-19,” Ferrer stressed. “It’s also important to remember that although you as an individual, particularly a younger adult, may not suffer these devastating consequences from COVID-19, you could infect someone you love, and that could be a relative or friend, and you could infect someone in your community, who could get very sick, and unfortunately pass away.”

That’s why the county is spearheading a new educational campaign to target young people amid the coronavirus crisis. Officials encouraged younger individuals to share their stories on social media using #TheRiskIsReal, and will be putting up billboards cautioning about the effects of COVID-19.

Ferrer on Wednesday reported 68 new coronavirus-related deaths, bringing the total number of fatalities in the county to 4,825. Ferrer noted that number of new total cases she reported Wednesday could be higher after technology issues in California’s lab reporting system resulted in an undercount of local cases. So far, there are a total of 197,912 coronavirus cases in the county.