Safety and immunogenicity of a primary yellow fever vaccination under low-dose methotrexate therapy - a prospective multi-centre pilot study

Background: More people on immunosuppression live in or wish to travel to yellow fever virus (YFV)-endemic areas. Data on the safety and immunogenicity of yellow fever vaccination (YFVV) during immunosuppression are scarce. The aim of this study was to compare the safety and immunogenicity of a primary YFVV between travellers on methotrexate and controls. Methods: We conducted a prospective multi-centre controlled observational study from 2015-2017 in six Swiss travel clinics. 15 adults (nine with rheumatic diseases, five with dermatologic conditions and one with a gastroenterological disease) on low-dose methotrexate (≤20 mg/week) requiring a primary YFVV and 15 age and sex-matched controls received a YFVV. Solicited/unsolicited adverse reactions were recorded, YFV-RNA was measured in serum samples on days 3, 7, 10, 14, 28 and neutralising antibodies on days 0, 7, 10, 14, 28. Reesults: Patients´ and controls' median ages were 53 and 52 years; nine patients and ten controls were female. 43% of patients and 33% of controls showed local side effects (p = 0.71); 86% of patients and 66% of controls reported systemic reactions (p = 0.39). YFV-RNA was detected in patients and controls on day 3-10 post-vaccination and was never of clinical significance. Slightly more patients developed YFV-RNAaemia (day 3: n = 5 vs. n = 2, day 7: n = 9 vs. n = 7, day 10: n = 3 vs. n = 2, all p > 0.39). No serious reactions occurred. On day ten, a minority of vaccinees was seroprotected (patients: n = 2, controls: n = 6). On day 28, all vaccinees were seroprotected. Conclusions: First-time yellow fever vaccination was safe and immunogenic in travellers on low-dose methotrexate. Larger studies are needed to confirm these promising results.

Journal of Travel Medicine

Journal of Travel Medicine

27

1708-8305

N/A

6

6