Safety and efficacy of influenza vaccination in a prospective longitudinal study of 31 children with juvenile idiopathic arthritis.

OBJECTIVES: Influenza vaccination in children with rheumatic diseases is often recommended, but not frequently performed. Our aim was to assess the safety and efficacy of annual influenza vaccination in a longitudinal follow-up study of an unselected group of children with juvenile idiopathic arthritis (JIA).
METHODS: Thirty-one children with stable JIA (10 boys, 21 girls, mean age 11.0 years) receiving various therapies and 14 children in a control group (10 boys, 4 girls, mean age 11.9 years) were vaccinated with the annual influenza vaccine Begrivac® 2008/2009. The children in both groups were followed for adverse events and infections 6 months after vaccination. Autoantibodies production and antibody titers against three vaccine viruses were determined in serial samples taken before, 1 and 6 months after vaccination.
RESULTS: Eleven (35%) children with JIA and 5 (36%) children in the control group reported short-term adverse events. A JIA flare was observed one month after vaccination in 4 (13%) patients, and in the following five months in 7 (23%) patients. The response to vaccination after one month was significant in the control and study groups as a whole, but not in a subgroup of 4 children receiving anti-TNF-α therapy. After six months, no significant differences in the protective titers against vaccine viruses among the patient and control groups were observed. Changes in the mean values of autoantibodies after vaccination were found only for IgG aCL in the JIA group.
CONCLUSIONS: No long-term adverse events were reported after influenza vaccination in JIA and control group. Thirty-five percent of children with JIA experienced flare of the disease after vaccination. Protective antibodies against at least 2 vaccine viruses 6 months after vaccination were detected in all patients.