Methods: 17 JIA patients immediately pre-etanercept (Group 1) and 10 JIA patients on stable dose of methotrexate (Group 2) will receive one dose of PPV23. All patients will be evaluated pre-vaccination, 2 months and 12 months post-vaccination for seven pneumoccocal serotypes. Serology will be performed by enzyme immunoassay and the immunogenicity endpoints will include seroprotection (SP), seroconversion (SP) and geometric mean concentration of antibodies (GMC). Clinical and laboratorial parameters of JIA will be evaluated before and after vaccination.