Table 3. Incidence and incidence rate ratios of health eventsa in vaccinees compared with controls, Canada 2017/18 and 2018/19 (n = 91,549).
| Type and number of participants with vaccine administered where applicable | Incidence or IRR of health events with 95% CI per age group | Total | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 6 months–4 years | 5–14 years | 15–64 years | ≥ 65 years | |||||||
| 2017/18 | Incidence | 95% CI | Incidence | 95% CI | Incidence | 95% CI | Incidence | 95% CI | Standardised incidence | 95% CI |
| Controls n = 13,578 | 8.70 | 6.34–11.57 | 4.74 | 3.49–6.28 | 2.44 | 2.11–2.80 | 0.97 | 0.69–1.32 | 2.44 | 2.28–2.61 |
| Vaccinees n = 30,173 | 8.82 | 7.57–10.20 | 5.41 | 4.55–6.36 | 3.17 | 2.92–3.44 | 1.25 | 1.02–1.51 | NA | NA |
| 2017/18 | IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | Standardised IRR | 95% CI |
| Agriflu trivalent (Seqirus) n = 4,992 | 3.07 | 1.26–7.45 | 1.05 | 0.15–7.27 | 0.77 | 0.57–1.04 | 1.06 | 0.63–1.79 | 1.21 | 1.11–1.32 |
| FluLaval quadrivalent (GSK) n = 462 | 0.83 | 0.51–1.36 | 1.41 | 0.58–3.43 | NA | NA | NA | NA | 0.36 | 0.32–0.41 |
| FluMist quadrivalent (AstraZeneca) n = 964 | 0.77 | 0.47–1.28 | 0.67 | 0.40–1.14 | NA | NA | NA | NA | 0.72 | 0.61–0.86 |
| Fluviral trivalent (GSK) n = 10,091 | 0.98 | 0.37–2.61 | 0.42 | 0.10–1.71 | 1.28 | 1.05–1.56 | 1.28 | 0.84–1.95 | 1.09 | 1.00–1.20 |
| Fluzone quadrivalent (Sanofi Pasteur) n = 8,972 | 1.10 | 0.78–1.54 | 1.34 | 0.96–1.87 | 1.57 | 1.30–1.91 | 2.16 | 1.18–3.94 | 1.53 | 1.41–1.67 |
| Influvac trivalent (Abbott) n = 4,597 | NA | NA | NA | NA | 1.44 | 1.13–1.83 | 1.25 | 0.75–2.07 | 1.40 | 1.26–1.56 |
| Unknown/missing/other n = 95 | 1.64 | 0.55–4.87 | 1.76 | 0.26–11.72 | NA | NA | NA | NA | 0.52 | 0.47–0.59 |
| 2018/19 | Incidence | 95% CI | Incidence | 95% CI | Incidence | 95% CI | Incidence | 95% CI | Standardised incidence | 95% CI |
| Controls n = 21,999 | 5.48 | 4.20–7.02 | 5.10 | 4.20–6.15 | 2.64 | 2.40–2.94 | 1.01 | 0.80–1.27 | 2.45 | 2.30–2.62 |
| Vaccinees n = 25,799 | 8.58 | 7.30–9.99 | 4.77 | 3.90–5.83 | 3.58 | 3.30–3.89 | 1.21 | 1.00–1.49 | NA | NA |
| 2018/19 | IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | Standardised IRR | 95% CI |
| FluLaval quadrivalent (GSK) n = 4,637 | 1.71 | 1.15–2.54 | 0.92 | 0.55–1.53 | 1.73 | 1.44–2.08 | 1.35 | 0.50–3.66 | 1.03 | 0.93–1.15 |
| FluMist quadravalent (AstraZeneca) n = 878 | 1.46 | 0.89–2.39 | 0.85 | 0.56–1.28 | NA | NA | NA | NA | 1.07 | 0.90–1.27 |
| Fluviral trivalent (GSK) n = 11,625 | 3.22 | 1.12–9.26 | 1.03 | 0.39–2.73 | 1.12 | 0.93–1.35 | 1.02 | 0.72–1.43 | 1.30 | 1.19–1.42 |
| Fluzone high dose trivalent (Sanofi Pasteur) n = 64 | NA | NA | NA | NA | NA | NA | 5.70 | 1.86–17.49 | 1.50 | 1.41–1.67 |
| Fluzone quadrivalent (Sanofi Pasteur) n = 5,910 | 1.50 | 1.10–2.06 | 1.03 | 0.73–1.45 | 1.51 | 1.25–1.84 | 2.54 | 1.36–4.76 | 1.56 | 1.44–1.70 |
| Influvac trivalent (Abbott) n = 2,437 | NA | NA | NA | NA | 0.94 | 0.67–1.32 | 1.40 | 0.79–2.47 | 1.02 | 0.92–1.14 |
| Unknown/missing/other n = 248 | 2.43 | 0.65–9.05 | NA | NA | 1.81 | 0.95–3.47 | NA | NA | 1.30 | 1.19–1.42 |
CI: confidence interval; IRR: incidence rate ratio; NA: not applicable (in most cases, the vaccine in question did not cause any health events in the specific age group therefore an IRR could not be calculated. Fluzone high dose vaccine was only given to adults aged ≥ 65 years and Flumist was only given to children aged < 15 years).
a A health event was defined by the respondent as of sufficient intensity to cause a medical consultation or work/school/day care absenteeism/prevent daily activities, or both.
The bold font indicates higher risk in vaccinees compared with controls.