RT Journal Article SR Electronic T1 Preventing the introduction of SARS-CoV-2 into school settings JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E24 OP E25 DO 10.1503/cmaj.202568 VO 193 IS 1 A1 Nisha Thampi A1 Beate Sander A1 Michelle Science YR 2021 UL http://www.cmaj.ca/content/193/1/E24.abstract