Table 2

Serological data before and after influenza a pandemic (pH1N1) 2009 vaccine in controls and RA patients (total population, RF and medication subsets)

PrevaccinationPosvaccination
SubsetGMTSeroprotectionGMTSeroprotectionFactor increaseSeroconversion
Controls(234)9.3(8.2 to 10.5)11.5(7.4 to 15.6)122.9(103.5 to 146.0)82.9(77.5 to 87.5)13.2(11.1 to 15.8)76.9(71.0 to 82.2)
RA group(340)8.0(7.3 to 8.8)10.8(7.5 to 14.1)57.5(48.0 to 68.9)*60.0(54.5 to 65.3)*7.2(6.1 to 8.5)*53.2(47.8 to 58.6)*
RF (340)
No (91)7.8(6.5 to 9.4)9.6(3.3 to 16.0)48.1(33.2 to 69.6)*54.2(43.4 to 65.0)*6.2(4.4 to 8.7)*48.2(37.4 to 59.0)*
Yes (249)7.9(7.1 to 8.8)*10.0(6.3 to 13.8)59.6(48.2 to 73.6)*64.5(55.4 to 67.5)*7.5(6.2 to 9.2)*54.2(48.0 to 60.4)*
Corticosteroids
No (93)7.8(7.0 to 8.6)*10.1(6.4 to 13.9)58.4(47.1 to 72.5)*60.3(54.2 to 66.4)*7.5(6.2 to 9.2)*54.7(48.4 to 60.9)*
Yes (247)8.6(7.2 to 10.4)12.9(6.1 to 19.7)55.1(39.4 to 77.0)*59.1(49.0 to 69.2)*6.4(4.7 to 8.7)*49.5(39.2 to 59.7)*
Methotrexate
No (125)8.0(6.9 to 9.2)12.9(7.0 to 12.8)90.9(66.3 to 124.9) 71.8(63.8 to 79.7)*11.4(8.4 to 15.4) 65.3(56.9 to 73.7)
Yes (215)8.0(7.1 to 9.0)9.7(5.8 to 13.7)44.2(35.7 to 54.7)*53.2(46.6 to 59.9)*5.5(4.6 to 6.7)*46.3(39.6 to 53.0)*
Chloroquine
No (216)7.6(6.8 to 8.5)10.1(6.1 to 14.2)57.4(45.4 to 72.6)*60.8(54.3 to 67.3)*7.5(6.1 to 9.3)*55.3(48.7 to 61.9)*
Yes (124)8.7(7.5 to 10.1)12.2(6.4 to 18.0)57.7(43.5 to 76.5)*58.5(49.8 to 67.3)*6.6(5.1 to 8.7)*49.6(40.7 to 58.5)*
Leflunomide
No (194)8.8(7.7 to 9.9)12.9(8.2 to 17.6)49.2(39.1 to 61.9)*56.7(49.7 to 63.7)*5.6(4.6 to 6.8)*50.5(43.5 to 57.6)*
Yes (146)7.1(6.3 to 7.9)*8.3(3.8 to 12.7)71.3(53.5 to 95.1)*64.8(57.0 to 72.6)*10.1(7.6 to 13.4)*57.2(49.1 to 65.3)*
Anti-TNF
No (293)8.1(7.2 to 8.9)11.2(7.4 to 15.0)55.5(45.1 to 68.3)*58.8(52.9 to 64.8)*6.8(5.8 to 8.3)*51.0(45.0 to 57.0)*
Yes (47)7.5(6.1 to 9.3)8.7(0.5 to 16.9)71.9(45.4 to 114.1)*67.4(53.7 to 81.1)*9.6(5.4 to 8.1)*67.4(53.7 to 81.1)
  • Data are expressed in percentages or value (95% CI).

  • Anti-TNF agents adalimumab, infliximab or etanercept; medications prescribed to less than 10% of the patients were not included. GMT significantly increased in controls, RA patients and all the subsets.

  • * p <0.05, subsets compared with control group;

  • p<0.05, comparison with or without the specific medication within a group.

  • Factor increase in GMT after vaccination.

  • GMT, geometric mean titre; RA, rheumatoid arthritis; RF, rheumatoid factor; TNF, tumour necrosis factor.