ROCHESTER — Mayo Clinic says it will require employees to be vaccinated against the coronavirus by mid-September, becoming one of the latest health systems to do so as delta variant cases rise around the country.

The Rochester-based medical system said the “vast majority” of its employees are already vaccinated. But it said all employees must be fully vaccinated against COVID-19 or complete an opt-out process by Sept. 17.

“Our patients expect to be safe when they come to Mayo Clinic, and we need to do everything we can to protect everybody,” Dr. Gianrico Farrugia, the clinic’s president and CEO, said in a statement Monday.

Staff who decline to be vaccinated must complete education modules and will be required to wear masks and socially distance at work.

Mayo said it is joining dozens of health systems nationwide in requiring vaccinations because of increasing cases of COVID-19 nationally, poor vaccination rates in many communities and the threat of variants.

Health Commissioner Jan Malcolm said Monday that Minnesota is not actively considering vaccination mandates but that she welcomes it when employers voluntarily take such steps.

“We encourage that, we applaud when employers do make that step,” Malcolm said at a briefing. “Health care employers certainly are in a position to play a real leading role here, and we appreciate that they are looking very seriously at that.”