The county remains at risk of having to bring back recently eased restrictions aimed at reducing the spread of the coronavirus while the number of cases continues to rise at San Diego State University, data released Thursday shows.

With no end to the pandemic in sight, SDSU officials on Thursday also announced classes in the spring 2021 semester would be online.

The announcement from SDSU President Adela de la Torre and Provost Salvador Hector Ochoa followed an update from California State University Chancellor Timothy White that all campuses in the system will continue with mostly virtual instruction for spring 2021 and continue offering housing with limited density.

Public health officials reported 284 new cases among San Diego County residents, including another 69 at SDSU, bringing the county’s total to 41,608. SDSU has a total of 509 confirmed cases among students, with another four considered probable cases.

The 69 new cases at the school reported Thursday shows the virus may be continuing to spread rapidly, as the school reported 44 new cases one day earlier.

The virus-related deaths of three women and one man between Aug. 31 and Sept. 9 brought the county’s death total during the pandemic to 725. The age of the four new fatalities ranged from early 60s to late 80s, and all had underlying medical conditions.

The 284 new cases reported Thursday was up from 247 reported Wednesday. The county still has not crossed a state threshold that could result in more restrictions on businesses and activities, but it is close.

A new statewide metric shows four color-coded tiers that range from purple for widespread to yellow for minimal, with each tier based on COVID-19 cases and rates of positive results from tests.

San Diego County is at Tier 2, in red, just below the most serious tier, but county health officials are concerned that local numbers are moving in the wrong direction.

On Thursday, the county’s daily case rate remained at 6.9 percent per 100,000 residents, inching just two-tenths away from qualifying for Tier 1. The case rate would have to be greater than 7.0 for two straight weeks before causing a shift from red to purple.

When the monitor system went into effect Aug. 31, San Diego County had a 5.8 percent case rate.

Also concerning is the rising percent of tests that come back positive, though that number is comfortably below the rate that could lead to more restrictions.

The county’s rolling average positivity rate increased from 3.4 percent on Aug. 31 to 4.4 percent Thursday. A rate of 8 percent over two weeks could lead to a shift to Tier 1.

The number of community-setting outbreaks also remains higher than the threshold that calls for the county to take action. A community-setting outbreak is defined as three or more positive cases from a gathering of people from different households over 14 days.

A report of seven such outbreaks over seven days is the trigger for action, and the county has confirmed 23 outbreaks over the past week. The latest outbreaks reported Thursday include one in a business setting and two in private residences.

The pandemic has not stressed the county’s medical system, but has hospitalized thousands. The latest figures show 3,253 people have been hospitalized, representing 7.8 percent of all local cases.

Of those hospitalized, 775 patients have required intensive care, representing 1.9 percent of all cases and 23.8 percent of people hospitalized with COVID-19.

At SDSU, the number of reported cases is growing daily. The 513 cases reported Thursday was eight times larger than the first number reported just about a week ago.

The university’s fall semester began Aug. 24 with the vast majority of classes held online and only about 8,000 out of 35,500 enrolled students attending in-person classes that required hands-on work.

Those classes were halted just nine days later with the university’s announcement that 64 coronavirus cases at the school had been confirmed.

Because of reports that students were not practicing health protocols on and around campus and were continuing to party at fraternity and sorority houses, the university also announced it was cracking down and citing violators of the public health order aimed at controlling the spread of the virus.

Thursday also saw the announcement of a planned press conference this morning to officially kick off a 14-day rotating program of COVID-19 testing in communities hit hardest by the pandemic.

In August, the San Diego Association of Governments released a report that found Black and Latino populations were three times as likely to live in areas with both high unemployment and high cases of the virus when compared with White workers.

The report also found 63 percent of Latinos and 58 percent of Blacks lived in county ZIP codes hit hardest by unemployment. It also found 53 percent of Blacks and 52 percent of Latinos lived in areas with the highest number of virus cases.

The press conference today will be held at the Mexican Consulate in Little Italy, the site of the first rotating testing program. Other locations and a full calendar of testing dates are expected to be released within a week.