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.

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.

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).

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.