Excitedly anxious: London, Ont. teachers on first day of school amid rise in COVID-19 cases The health unit said all unvaccinated close contacts need to stay home from school and quarantine.In order to keep children in school, the health unit is emphasizing the importance of everyone going into schools each morning to complete a COVID-19 screening tool before leaving the house.In addition to the Ontario Government’s health and safety measures in schools, the Middlesex-London Health Unit has also made recommendations for area schools, which include additional preventive measures for school settings to decrease the risk of COVID-19 transmission in schools..