Hepatitis B vaccine and juvenile idiopathic arthritis: comparison of the seropositivity rates with healthy children at the time of diagnosis and booster dose response under treatment.

Introduction/objectives: The study aimed to determine whether in children with newly diagnosed juvenile idiopathic arthritis (JIA) hepatitis B surface antibody (anti-HBs) differs from healthy children and to see whether the revaccination is safe and effective under JIA treatment.

Methods: Patients who were followed up with a diagnosis of JIA between January 2020 and February 2024 were included. The control group consisted of healthy children matched for age and gender. Patients with JIA who were seronegative and revaccinated against hepatitis B virus (HBV) at follow-up visits were evaluated in terms of antibody responses and side effects after vaccination.

Results: The study included 187 patients with JIA, 104 (55.6%) girls. In the JIA group, the mean anti-HBs levels were 120.8 ± 228.3 IU/L, and 64.7% of patients had anti-HBs levels ≥ 10 mIU/ml, while in the control group, the mean anti-HBs levels were 184.9 ± 304.4 IU/L, and 68.7% of children had protective antibody level against HBV. Sixty-six patients with JIA in whom anti-HBs level < 10 IU/L received an additional three doses of HBV vaccine. After booster vaccination, only one patient had anti-HBs level < 10 IU/L; in the other 65 JIA patients, the mean anti-HBs levels were 530.4 ± 320.8 IU/L. None of the patients observed serious side effects or JIA exacerbation after vaccination.

Conclusions: Although the mean anti-HBs levels in newly diagnosed JIA patients were lower than in healthy children, no difference was found in the seropositivity rates. Vaccination against HBV during JIA treatment is safe and effective and should be encouraged. Key Points • Hepatitis B virus infection remains a public health problem and publications are indicating that vaccine responses may be lower in autoimmune diseases such as juvenile idiopathic disease. • The mean antibody levels against the HBV vaccine in newly diagnosed JIA patients were lower than in healthy children. • The fact that patients diagnosed with JIA were revaccinated under treatment and no side effects were observed will support the vaccination of these patients.