The University of Iowa Athletic Department has reported that more positive COVID-19 tests have been returned. The school released a statement on Monday.

For the week of June 29-July 5, Iowa’s athletic department conducted five COVID-19 tests. Four of those returned positive and one was negative. The testing on campus began on May 29, as student-athletes, staff and coaches started returning for voluntary workouts when the NCAA lifted its moratorium on team activities on June 1.

“Following the positive test result, protocol established by UI Athletics and medical staff, including contact tracing procedures, is being followed to ensure the safety of all IU Athletics student-athletes and staff,” the school said. “This mandatory protocol also includes isolation for the individuals who test positive, and quarantine for those individuals who might have been exposed to someone with the virus.”

Since Iowa began testing, it has conducted 413 screenings. Of those tests, there have been 21 confirmed positive results and 392 negative tests.

Several schools from across the country have reported multiple positive tests since allowing student-athletes to return to campus. Some, like Kansas, Kansas State and Houston, have halted voluntary workouts temporarily due to an influx in positive test results.