title: Reduced seroprotection after pandemic H1N1 influenza adjuvant-free vaccination in patients with rheumatoid arthritis: implications for clinical practice.
abstract: BACKGROUND
  Reduced response to pandemic (2009) H1N1 (pH1N1) vaccine in patients with rheumatoid arthritis (RA) was recently reported.
  
  
  OBJECTIVE
  To evaluate the contribution of age, disease activity, medication and previous antibody levels to this reduced response.
  
  
  METHODS
  340 adult RA patients and 234 healthy controls were assessed before and 21 days after adjuvant-free influenza A/California/7/2009 (pH1N1) vaccine. Disease activity (DAS28), current treatment and pH1N1 antibody titres were collected. Seroprotection, seroconversion and factor increase in geometric mean titre (GMT) were calculated and adverse events registered.
  
  
  RESULTS
  RA and controls showed similar (p>0.05) prevaccination GMT (8.0 vs 9.3) and seroprotection (10.8% vs 11.5%). After vaccination a significant reduction (p<0.001) was observed in all endpoints: GMT and factor increase in GMT, seroprotection and seroconversion rates. Disease activity did not preclude seroconversion or seroprotection and remained unchanged in 97.4% of patients. Methotrexate was the only disease-modifying antirheumatic drug associated with reduced responses (p=0.001). Vaccination was well tolerated.
  
  
  CONCLUSIONS
  The data confirmed both short-term anti-pH1N1 vaccine safety and, different from most studies with seasonal influenza, reduced seroprotection in RA patients, unrelated to disease activity and to most medications (except methotrexate). Extrapolation of immune responses from one vaccine to another may therefore not be possible and specific immunisation strategies (possibly booster) may be needed. Clinicaltrials.gov no NCT01151644.
authors.affiliation: Division of Rheumatology, Faculdade de Medicina da Universidade de São Paulo, Brazil.
authors.forename: Ana C M
authors.initials: AC
authors.lastname: Ribeiro
authors.forename: Lissiane K N
authors.initials: LK
authors.lastname: Guedes
authors.forename: Julio C B
authors.initials: JC
authors.lastname: Moraes
authors.forename: Carla G S
authors.initials: CG
authors.lastname: Saad
authors.forename: Nadia E
authors.initials: NE
authors.lastname: Aikawa
authors.forename: Ana Luisa
authors.initials: AL
authors.lastname: Calich
authors.forename: Ivan L A
authors.initials: IL
authors.lastname: França
authors.forename: Jozelio F
authors.initials: JF
authors.lastname: Carvalho
authors.forename: Percival D
authors.initials: PD
authors.lastname: Sampaio-Barros
authors.forename: Celio R
authors.initials: CR
authors.lastname: Goncalves
authors.forename: Eduardo F
authors.initials: EF
authors.lastname: Borba
authors.forename: Maria do Carmo S
authors.initials: Mdo C
authors.lastname: Timenetsky
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Precioso
authors.forename: Alberto
authors.initials: A
authors.lastname: Duarte
authors.forename: Eloisa
authors.initials: E
authors.lastname: Bonfa
authors.forename: Ieda M M
authors.initials: IM
authors.lastname: Laurindo
mesh_terms: D000276:Adjuvants, Immunologic; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000009:adverse effects / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D018501:Antirheumatic Agents; D007166:Immunosuppressive Agents; D007252:Influenza Vaccines; D008727:Methotrexate