Short and long-term effects of pandemic unadjuvanted influenza A(H1N1)pdm09 vaccine on clinical manifestations and autoantibody profile in primary Sjögren's syndrome

► Seroconversion and seroprotection rates are comparable to healthy controls. ► Short and long-term disease safety was demonstrated. ► Autoantibody induction: at long-term and within the SS spectrum. ► Vaccine induces long-term changes in SS autoantibodies without deleterious effect in disease course.