COVID cases at Cedar Grove school with masks optional News of COVID cases at mask-optional Cedar Grove school News of two positive cases of COVID-19 at Cedar Grove Middle School came a day after the district went mask-optional. CEDAR GROVE, Wis. - News of two positive cases of COVID-19 at Cedar Grove Middle School came a day after the district went mask-optional. Over the last year, we've almost come to expect a large sign on the door of a school or business saying "mask required," but you'll see no such signage at Cedar Grove. Masks are now optional in the district, and the superintendent says the two new positive cases are unrelated.