Table 1

Association between IIV and consultation for joint pain, new corticosteroid prescription and RA flare

OutcomeRisk periodEvents (n)Person-time (days)IRR (95% CI)*P value*
Joint pain
Unexposed99772 712 3731.00 < 0.001
15 days prevaccination788160 775 1.29 (1.20 to 1.39)
Postvaccination intervals
0–14 days479150 314 0.84 (0.77 to 0.92) < 0.001
15–30 days567160 8420.94 (0.86 to 1.02)0.127
31–60 days1121321 024 0.93 (0.88 to 0.99) 0.025
61–90 days1069319 890 0.90 (0.84 to 0.96) 0.001
Corticosteroid
prescription

Unexposed94702 266 0701.00<0.001
15 days prevaccination704135 4931.21 (1.12 to 1.31)
Postvaccination intervals
0–14 days539126 6251.00 (0.91 to 1.09)0.924
15–30 days554135 5150.96 (0.88 to 1.04)0.338
31–60 days1151270 1091.00 (0.95 to 1.07)0.876
61–90 days1182268 9681.04 (0.98 to 1.11)0.184
RA flare

Unexposed460153 2471.000.785
15 days prevaccination2489570.95 (0.64 to 1.41)
Postvaccination intervals
0–14 days2784000.97 (0.65 to 1.45)0.888
15–30 days2990001.12 (0.78 to 1.620.525
31–60 days5918 0001.06 (0.80 to 1.39)0.693
61–90 days4617 9780.81 (0.59 to 1.10)0.180
  • *Statistically significant results are in bold (p<0.05).

  • IIV, inactivated influenza vaccine; IRR, incidence rate ratio; RA, rheumatoid arthritis.