ABSTRACT
BACKGROUND: There is scarce evidence on fourth doses of SARS-CoV-2 vaccines in chronic kidney disease (CKD) patients. We have evaluated the humoral response and effectivity of the fourth dose in the CKD spectrum: non-dialysis CKD (ND-CKD), hemodialysis (HD), peritoneal dialysis (PD) and kidney transplant (KT) recipients. METHODS: This is a prespecified analysis of the prospective, observational, multicentric SENCOVAC study. In patients with CKD who had received a complete initial vaccination and one or two boosters and had anti-Spike antibody determinations 6 and 12 months after the initial vaccination, we analyzed factors associated to persistent negative humoral response and to higher anti-Spike antibody titers as well as the efficacy of vaccination on COVID-19 severity. RESULTS: Of 2186 patients (18% KT, 8% PD, 69% HD and 5% ND-CKD), 30% had received a fourth dose. The fourth dose increased anti-Spike antibody titers in HD (P = 0.001) and ND-CKD (P = 0.014) patients and seroconverted 72% of previously negative patients. Higher anti-Spike antibody titers at 12 months were independently associated to repeated exposure to antigen (fourth dose, previous breakthrough infections), previous anti-Spike antibody titers and not being a KT. Breakthrough COVID-19 was registered in 137 (6%) patients, of whom 5% required admission. Admitted patients had prior titers below 620 UI/ml and median values were lower (P = 0.020) than in non-admitted patients. CONCLUSIONS: A fourth vaccine dose increased anti-Spike antibody titers or seroconverted many CKD patients, but those with the highest need for a vaccine booster (i.e. those with lower pre-booster antibody titers or KT recipients) derived the least benefit in terms of antibody titers. Admission for breakthrough COVID-19 was associated with low anti-Spike antibody titers.
ABSTRACT
BACKGROUND: Chronic kidney disease (CKD) patients are at high-risk for severe coronavirus disease 2019 (COVID-19). The multicentric, observational and prospective SENCOVAC study aims to describe the humoral response and safety of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in CKD patients. Safety and immediate humoral response results are reported here. METHODS: Four cohorts of patients were included: kidney transplant (KT) recipients, and haemodialysis (HD), peritoneal dialysis (PD) and non-dialysis CKD patients from 50 Spanish centres. Adverse events after vaccine doses were recorded. At baseline and on Day 28 after the last vaccine dose, anti-Spike antibodies were measured and compared between cohorts. Factors associated with development of anti-Spike antibodies were analysed. RESULTS: A total of 1746 participants were recruited: 1116 HD, 171 PD, 176 non-dialysis CKD patients and 283 KT recipients. Most patients (98%) received mRNA vaccines. At least one vaccine reaction developed after the first dose in 763 (53.5%) and after the second dose in 741 (54.5%) of patients. Anti-Spike antibodies were measured in the first 301 patients. At 28 days, 95% of patients had developed antibodies: 79% of KT, 98% of HD, 99% of PD and 100% of non-dialysis CKD patients (P < 0.001). In a multivariate adjusted analysis, absence of an antibody response was independently associated with KT (odds ratio 20.56, P = 0.001) and with BNT162b2 vaccine (odds ratio 6.03, P = 0.023). CONCLUSION: The rate of anti-Spike antibody development after vaccination in KT patients was low but in other CKD patients it approached 100%, suggesting that KT patients require persistent isolation measures and booster doses of a COVID-19 vaccine. Potential differences between COVID-19 vaccines should be explored in prospective controlled studies.