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. Author manuscript; available in PMC: 2019 Jul 17.
Published in final edited form as: Vaccine. 2017 Apr 9;35(20):2668–2675. doi: 10.1016/j.vaccine.2017.03.082

Table 4.

Non-asthma related event rates in risk and comparison windows, and odds of adverse events, influenza immunizations between July 1, 2007 and March 31, 2014 for children 2–18 years of age with a history of asthma prior to the immunization, Kaiser Permanente Northern California.

Event Days after immunization Number of events Events per 100 K exposure daysa Odds Ratio (95% Confidence Interval) of adverse event in the exposure window compared to comparison window after vaccinationb
IIV LAIV IIV LAIV IIV LAIV Difference-in-Differences
Afebrile seizures 1–7 13 3 0.56 0.75 1.36 (0.58,3.19) 0.79 (0.14,4.30) 0.58 (0.09,3.86)
29–42 22 6 0.48 0.75
Bell’s palsy 1–14 1 1 0.02 0.13 c c c
29–42 3 0 0.06 0.00
Epistaxis 1–7 56 5 2.42 1.26 1.04 (0.69,1.57) 0.19 (0.04,0.80)* 0.18 (0.04,0.82)*
29–42 109 16 2.35 2.01
Fever 1–2 41 4 6.20 3.52 0.83 (0.56,1.23) 0.35 (0.10,1.26) 0.42 (0.11,1.61)
29–42 345 55 7.45 6.91
Febrile seizure 0–2 4 0 0.40 0.00 c c c
29–42 13 3 0.28 0,38
Gastrointestinal disorders 1–7 318 31 13.73 7.79 0.90 (0.77,1.06) 0.57 (0.35,0.93)* 0.63 (0.38,1.06)
29–42 688 111 14.86 13.95
Migraine 1–7 105 9 4.53 2.26 0.98 (0.73,1.32) 0.89 (0.32,2.44) 0.91 (0.32,2.59)
29–42 199 17 4.30 2.14
Otitis 1–7 110 13 4.75 3.27 0.77 (0.58,1.00) 0.58 (0.27,1.24) 0.75 (0.33,1.70)
29–42 298 39 6.43 4.90
Sinusitis 1–7 13 1 0.56 0.25 c c c
29–42 49 1 1.06 0.13
a

Because the risk and comparison time intervals are not equal for these adverse events, event rates are reported per 100k exposure days, rather than per 100k immunized children. “Exposure days” equals the number of children immunized times the number of days in the time interval.

b

For each immunization type, the odds ratio (OR) is the ratio of the odds of an event occurring in the risk interval and the odds of an event occurring in the comparison interval. The “difference-in-differences” is the ratio of the IIV odds ratio and the LAIV odds ratio. For the IIV and LAIV columns, values greater than (less than) one indicate increased (decreased) risk of the event following receipt of that vaccine. For the difference-in-differences column, values greater than (less than) one indicate that the risk of an event following LAIV is higher (lower) than the risk following IIV. IIV: inactivated influenza vaccine; LAIV: live attenuated influenza vaccine.

c

Events were too rare to allow for modeling.

*

Significant at p ≤ 0.05.