Statistical analysis: Immunogenicity and safety analyses will be descriptive and data will be presented as number (%) or median (range). The GMCs will be compared between JIA patients with and without anti-TNF therapy using a two-sided Student's t-test or Mann-Whitney U-test on the log10-transformed titers. The prospective analysis of GMCs for each of seven pneumococcal serotypes will be performed by Friedman Repeated Measures ANOVA on Ranks. Categorical variables (rates of seroprotection and seroconversion, prednisone and immunosuppressive drugs use) will be compared using Fisher's exact test. The prospective analysis of seroprotection and seroconversion rates for each of seven pneumococcal serotypes will be performed by McNemar's Test. The effects before and after vaccination on disease activity will be analyzed with the Wilcoxon signed ranks test. The statistical significance was set at p value < 0.05.