Table 2.
VE against influenza infection based on Canada’s sentinel surveillance system from 2010 to 2022 (2020-2021 season is not included in this table for its historically low incidence of influenza infection).
| Season (reference) | Vaccine strains of TIV | Circulating strain | VE (95% CI) | |||||
|---|---|---|---|---|---|---|---|---|
| Overall VE | VE against A(H1N1) pdm09 | VE against A/H3N2 | VE against B/Yamagata | VE against B/Victoria | ||||
| 2010-2011 (67) | A/(H1N1)pdm09/California/7, A/(H3N2)Victoria/210/2009 (NYMC X-187), B/Brisbane/60/2008(Victoria)-like strains | A(H1N1)pdm09, A/H3N2, influenza B |
37 (17-52) | 59 (14-80) | 39 (14-57) | 25 (-18-52) against influenza B | ||
| 2011-2012 (68) | A/(H1N1)pdm09/California/7, A/(H3N2)Victoria/210/2009 (NYMC X-187), B/Victoria- Brisbane/60/2008 | A(H1N1)pdm09, A/H3N2, B/Victoria, B/Yamagata |
59 (43-70) | 80 (52-92) | 51 (10-73) | 71 (40-86) | 27 (-21-56) | |
| 2012-2013 (69) | A/(H3N2)Victoria/361/2011-IVR-165, A/(H1N1)pdm09/California/7/NYMC-X- 179A/X-181, B/Hubei-Wujiagang/158/2009-NYMC-BX-39 | A/H3N2, A(H1N1)pdm09, B/Yamagata, B/Victoria | 50 (33-63) | 50 (16-80) | 41 (17-59) | 67 (30-85) | 75 (29-91) | |
| 2013-2014 (70) | A/(H1N1)pdm09(X-179A/X-181A), A/H3N2-X-223A, B/Yamagata-BX-51B | A(H1N1)pdm09, A/H3N2, B/Yamagata (B/Wisconsin, B/Massachusetts) |
68 (58-76) | 71 (58-80) | -34 (-280-53) | 73 (57-84) (72 (53-83) against B/Massachusetts) | NE | |
| 2014-2015 (71) | A/(H1N1)pdm09(X-179A/X-181A), A/H3N2-X-223A, B/Yamagata-BX-51B | A/H3N2, B/Yamagata (B/Wisconsin) |
9 (-14-27) | NE | -17 (-50-9) | 42 (10-62) (42 (8-63) against B/Wisconsin) | NE | |
| 2015-2016 (72) | A/(H1N1)pdm09(X-179A/X-181A), A/H3N2-NIB-88, B/Yamagata-Phuket/3073/2013 | A(H1N1)pdm09, A/H3N2, B/Yamagata, B/Victoria |
46 (32-57) | 43 (25-57) | NE | NE | 54 (32-68) | |
| 2016-2017 (73) | A/(H1N1)pdm09- California/7, A/H3N2-Hong Kong/4801/2014, B/Victoria- Brisbane/60/2008 | A/H3N2, A(H1N1)pdm09, B/Yamagata, B/Victoria | 43 (28-55) | NE | 36 (18-50) | 72 (47-85) | NE | |
| 2017-2018 (73) | A/(H1N1)pdm09- Michigan/45/2015, A/H3N2-Hong Kong/4801/2014, B/Victoria- Brisbane/60/2008 | A/H3N2, A(H1N1)pdm09, B/Yamagata, B/Victoria | 34 (22-45) | 52 (18-72) | 14 (-8-31) | 44 (30-55) | NE | |
| 2018-2019 (74) | A/(H1N1)pdm09- Michigan/45/2015, A/H3N2-Hong Kong/4801/2014, B/Victoria- Brisbane/60/2008 | A(H1N1)pdm09, A/H3N2, B/Victoria |
68 (55-77) | 72 (60-81) | NE | NE | NE | |
| 2019-2020 (75) | A(H1N1)pdm09 - Brisbane/02/2018, A(H3N2) - Kansas/14/2017, B/Victoria- Brisbane/60/2008 |
A(H1N1)pdm09, A/H3N2, B/Victoria |
58 (47-66) | 44 (26-58) | 62 (37-77) | 69 (57-77) against influenza B | ||
| 2021-2022 (76) | A(H1N1)pdm09 - Brisbane/02/2018, A(H3N2) - Kansas/14/2017, B/Victoria- Brisbane/60/2008 |
A/H3N2 | 36 (-38-71) | NE | NE | NE | NE | |
TIV, trivalent influenza vaccine; CI, confidence interval; VE, vaccine effectiveness; NE, not estimated owing to insufficient sample size.