Table 4. Incidence risk ratios for health eventsa in vaccinees compared with controls, Canada 2017/18 and 2018/19 (n = 91,549).
| Signs and symptoms | 6 months–4 years IRR |
95% CI | 5–14 years IRR |
95% CI | 15–64 years IRR |
95% CI | ≥ 65 years IRR |
95% CI | Total standardised IRR |
95% CI |
|---|---|---|---|---|---|---|---|---|---|---|
| 2017/18 | ||||||||||
| Fever (≥ 38 °C) | 1.25 | 0.78–2.00 | 2.11 | 1.17–3.79 | 1.45 | 1.02–2.06 | 0.98 | 0.42–2.29 | 1.47 | 1.24–1.74 |
| Stopped eating (children onlyb) | 0.86 | 0.53–1.39 | 1.36 | 0.77–2.40 | ND | ND | ND | ND | 1.10 | 0.85–1.42 |
| Sore throat | 0.69 | 0.38–1.24 | 0.96 | 0.59–1.57 | 0.98 | 0.79–1.23 | 1.31 | 0.72–2.36 | 0.99 | 0.86–1.13 |
| Feeling unwell/fatigue/ weakness/muscle aches/joint pain | 0.66 | 0.41–1.04 | 1.09 | 0.70–1.67 | 1.34 | 1.10–1.63 | 1.37 | 0.82–2.28 | 1.21 | 1.08–1.36 |
| Respiratoryc | 0.69 | 0.45–1.06 | 0.83 | 0.49–1.38 | 0.97 | 0.76–1.23 | 0.93 | 0.54–1.60 | 0.89 | 0.78–1.01 |
| Gastrointestinal problems | 1.33 | 0.72–2.45 | 1.22 | 0.72–2.06 | 1.31 | 0.97–1.77 | 3.55 | 1.25–10.09 | 1.41 | 0.78–1.01 |
| Migraine/headache | 0.93 | 0.35–2.49 | 0.92 | 0.57–1.49 | 1.41 | 1.12–1.78 | 1.59 | 0.83–3.04 | 1.32 | 1.15–1.51 |
| 2018/19 | ||||||||||
| Fever (≥ 38 °C) | 1.90 | 1.21–2.99 | 1.89 | 1.17–3.05 | 1.22 | 0.88–1.69 | 1.73 | 0.80–3.75 | 1.53 | 1.27–1.84 |
| Stopped eating (children onlyb) | 0.03 | 0.00–0.20 | NA | NA | NA | NA | NA | NA | 0.01 | 0–0.08 |
| Sore throat | 1.39 | 0.74–2.59 | 0.55 | 0.36–0.86 | 0.88 | 0.72–1.07 | 1.64 | 0.99–2.72 | 0.90 | 0.79–1.03 |
| Feeling unwell/fatigue/ weakness/muscle aches/joint pain | 1.27 | 0.84–1.94 | 0.80 | 0.57–1.13 | 1.36 | 1.15–1.60 | 1.40 | 0.93–2.13 | 1.26 | 1.13–1.40 |
| Respiratoryc | 1.33 | 0.88–2.01 | 0.59 | 0.39–0.90 | 1.01 | 0.82–1.24 | 1.33 | 0.82–2.14 | 0.99 | 0.87–1.13 |
| Gastrointestinal problems | 1.46 | 0.87–2.44 | 1.01 | 0.64–1.60 | 1.60 | 1.19–2.15 | 2.24 | 1.03–4.90 | 1.46 | 1.23–1.74 |
| Migraine/headache | 0.91 | 0.37–2.22 | 0.95 | 0.60–1.52 | 1.24 | 1.02–1.51 | 2.24 | 1.23–4.11 | 1.25 | 1.09–1.43 |
CI: confidence interval; IRR: incidence rate ratio; NA: not applicable; ND: not determined.
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.
b Children are aged 6 months–14 years .
c Respiratory is defined as upper/lower tract infection symptoms, including asthma.
Allergic-like-illness, anaesthesia/paraesthesia, anaphylaxis, oculorespiratory syndrome, and seizures did not occur in both cases and controls.
The bold font indicates higher risk in vaccinees compared with controls.