Effectiveness and safety oy yellow fever vaccine in patients with primary Sjögren's syndrome

Background. Yellow fever is a viral haemorrhagic fever transmitted by mosquitoes. The live attenuated vaccine is highly immunogenic and offers prolonged and generally safe protection in immunocompetent patients. The aim of this study is to evaluate the immunogenicity and safety of the vaccine in patients with primary Sjögren syndrome (PSS) in the short and long term. Methods. This is a phase IV controlled prospective study, including 50 patients with PSS and 29 healthy controls. All of them were vaccinated for the first time by the 17DD YF vaccine (Biomanguinhos, Brasil) after individual clinical evaluation. Patients who presented CD4 <200 cells/mm3, neoplasia, HIV, primary immunodeficiency, using cyclophosphamide, prednisone >20mg/d, azathioprine >2mg/kg/d, chlorambucil, mycophenolate or biological therapy were excluded. Patients were evaluated at baseline, after 3, 4, 5, 6, 7, 14 and 30 days of the vaccination for viremia and humoral response. Plaque reduction neutralization test (PRNT) was measured at baseline and after 28 days. Disease activity was evaluated at baseline and after 6 months. Serum and cell samples were frozen at -70°C. The analyses of viremia and PRNT will be processed by Instituto Fiocruz-BH and Fundacão Biomanguinhos-RJ. Results. The mean age was 53 (±15.5) years, ESSDAI 1.2 (±2.4), ESSPRI 3.6 (±2.9), PCR 3.3 (±4.2), C3 174.2 (±266.2), C4 26.3 (±10.7) and IgG 1555.8 (±769.5). Most patients showed disease under control before and after 6 months (p=0.556). Forty four percent of the patients were using hydroxychloroquine, 18% methotrexate, 4% leflunomide, 2.3%, sulfasalazine and 2% corticosteroid. Nine patients had adverse events from the 21 who were using only one medication and all 4 patients who were using 2 medications had an adverse event, and the patient who was using 3 medications did not have any adverse event (p=0.066). There was no difference between patients and controls in the occurrence of adverse events (46% vs 27.6%, p=0.106). The main local symptoms were: pain (16%), nodule (2%), oedema ( 4%) and heat (2%). The main systemic adverse events were: malaise (24%), myalgia (20%), headache (12%), arthralgia (12%), low back pain (10%), weakness in limbs (10% ), productive cough (10%), dry cough (8%), pruritus (8%), abdominal pain (6%), nausea (6%), vomit (6%), fever (4%), dyspnoea (4%) e diarrhoea (2%). Conclusion. The yellow fever vaccine is safe in patients with PSS with low disease activity and under low immunossupression. It is necessary to await the studies of vaccine kinetics for further conclusions.