An open label, uncontrolled clinical trial of immunogenicity and safety of yellow fever vaccine in adults with chronic kidney disease as compared to immunocompetent

Background: During a yellow fever (YF) epidemic in Brazil, vaccination campaigns targeting the entire population in the affected areas were conducted, bringing up an opportunity to prospectively evaluate YF vaccine’s immunogenicity and safety in adults with chronic kidney disease (CKD) compared to healthy adults.Methods: Open-label trial involved adults aged ≥18 years with CKD on dialysis (CKD-D) or not (CKD-ND) and healthy, who denied previous YF vaccination. All them received a YF vaccine standard dose. Adverse events (AE) were monitored within 15 days after vaccination. Neutralizing antibodies were measured by microneutralization test with 50% reduction of lysis plaques (micro-PRN50). Viremia was evaluated by RT-PCR.Results: 154 participants were included: 54 CKD-D, 41 with CKD-ND and 59 healthy. Median age was 50, 61 and 47 years, respectively. Ten days after vaccination (D10), seropositivity was significantly lower in CKD (CKD-ND, 62.3%; CKD-D, 48%) than in healthy (86.7%) and CKD participants had lower antibody geometric mean titers (GMT). On D30, GMT increased in all three groups, and seropositivity rates and GMT of CKD and healthy groups were not significantly different. On D365, most participants in the three groups persisted seropositive, with a GMT decrease in all three groups, without significant differences. On D10, viremia was detected in 28.8% of CKD-D; 32.3% of CKD-ND, and 28.9% of healthy, without significant difference between groups, but CKD participants had lower viremia. Healthy participants more frequently reported AE (66.7%) than CKD-ND (48.5%) and CKD-D (48.8%). Most common AE were headache (32.7%), myalgia (28.4%) and injection site pain (25.3%). Conclusions. CKD adults had a robust although delayed neutralizing antibody response to YF vaccine. The vaccine was well-tolerated by adults with CKD, but the sample size did not allow conclusions on vaccine-related severe AE.