Season 2014–2015Period at riskIncidence (per 1000 person-years)
(95% CI)
Relative risk
(95% CI)
LAIV recipients
(n=6745)
Matched unvaccinated children
(n=20 163)
IIV recipients
(n=6738)
Versus unvaccinated childrenVersus
IIV recipients
Hypersensitivity3 days27
(3 to 98)
n*=2
14
(3 to 40)
n*=3
41
(8 to 119)
n*=3
2.00
(0.26 to 12.07)
0.66
(0.02 to 2.60)
Seizures/convulsions42 days28
(17 to 42)
n*=22
17
(12 to 24)
n*=36
66
(49 to 87)
n*=52
1.65
(0.95 to 2.80)
0.42
(0.25 to 0.69)
Vasculitis3
(0 to 9)
n*=2
1
(0 to 4)
n*=3
3.00
(0.20 to 9.94)
  • *Number of incident cases.

  • IIV, inactivated influenza vaccine; LAIV, live attenuated influenza vaccine.