Figure 1.

Frequency of vaccination responses to the influenza antigens in patients with rheumatoid arthritis who withheld methotrexate for 1 week or 2 weeks and in healthy controls. Graphs show the percentage of participants in each group achieving a satisfactory vaccine response, defined as a ≥4‐fold increase in antibody titers, as determined with the hemagglutination inhibition assay, at 4 weeks postvaccination against ≥2 vaccine strains (A) and against ≥1, ≥3, and 4 vaccine strains (B). Bars show the mean ± 95% confidence interval. The 1‐week and the 2‐week methotrexate hold groups were compared by a chi‐square test.