The Sewanhaka Central High School District says nine other staff members were exposed to a sick person during a meeting last week.
All 10 will now have to quarantine for at least two weeks. Students set to return are concerned.
"Hopefully, everyone is going to be OK, but I think there is going to be another outbreak and I'm just concerned about that," says Katherine McWilliam, who is getting ready to start her junior year at the high school.
The district says the school is being disinfected and will be ready for classes to begin on Thursday as originally scheduled.