(CNN) As an Indiana school district welcomed students to the 2020-21 academic year, one of their students tested positive for Covid-19 on the first day of class, according to a letter sent to parents.The Hancock County Health Department notified Greenfield-Central Junior High School Thursday afternoon that one of their students, who had attended part of the school day, tested positive for Covid-19, Superintendent Harold Olin said in a letter.Olin said the school enacted its “Positive COVID-19 Test Protocol” once school officials became aware of the positive result.Teachers worry about how we’ll keep them safe if their schools reopen School officials immediately isolated the student within the school’s clinic, and they examined the student’s schedule, including transportation and extracurricular activities, to determine who had come in close contact.