RT Journal Article SR Electronic T1 Tdap vaccination in pregnancy JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E911 OP E911 DO 10.1503/cmaj.202420 VO 193 IS 24 A1 Daniel Dalcin A1 Scott A. Halperin YR 2021 UL http://www.cmaj.ca/content/193/24/E911.abstract