Evaluation of Yellow Fever Vaccine in Patients With Rheumatic Diseases Under Low Immunosuppression Level and Residing in a Risk Area

Detailed Summary

According to World Health Organization (WHO), since December 2016, Brazil is showing a significant increase in cases of yellow fever in humans. In view of this, vaccination is suitable for residents and travelers to the risk area. However, for immunosuppressed patients there is a formal recommendation not to vaccinate with live virus vaccine. On the other hand, the safety and efficacy of the vaccine has been demonstrated in patients with HIV, and safety and seroconversion have also been demonstrated in patients with rheumatic disease who were inadvertently revaccinated for yellow fever. Faced with the impossibility of leaving the high-risk area for some patients the vaccination could be released to only those who have low level of immunosuppression as suggested by some recommendations of medical societies. The availability of a fractional vaccine in the State of São Paulo, which has proved its efficacy, opens the possibility of exposure to a lower number of copies of the virus in the first exposure of immunosuppressed patients, allowing, if necessary, a safer revaccination, after 28 days to obtain of a more effective immunogenic response. The objectives of the study are to evaluate the immune response of the immunization with fractional yellow fever vaccine (neutralizing antibodies) in patients with systemic autoimmune rheumatic diseases residing in a high-risk area. Secondarily, evaluate the possible association between immunogenicity and vaccination with: demographic data, clinical and laboratory activity of the disease in patients with chronic rheumatic diseases, evaluate the curve of viremia and report adverse events. Patients and healthy controls will be vaccinated for yellow fever in the Immunization Center of Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). The patients' screening for exclusion and inclusion criteria will be done at the rheumatology outpatient clinic after medical evaluation. For the controls will be the routine screening of the Immunization Center. The vaccination protocol will be a fractional dose of the yellow fever vaccine on day D0 for both groups. Patients will be evaluated on day D0, D5, D10, D30-4 and D365 and controls only on days D0, D10, D30-45 and D365 for aspartate aminotransferase (AST), alanine aminotransferase (ALT), platelets, urea and creatinine, immunoglobulin M (IgM) by immunofluorescence for Yellow Fever, viremia, autoantibodies.

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