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.

Los pacientes en diálisis constituyen un grupo de riesgo de sufrir infección por SARS-CoV-2 y posiblemente de tener más complicaciones. Los profesionales sanitarios se han enfrentado a una pandemia sin precedentes y de la que había poca información. El objetivo de este estudio ha sido describir la experiencia del primer mes viviendo la pandemia generada por SARS-CoV-2 en una unidad hospitalaria de hemodiálisis de Madrid, tanto en relación a los pacientes como al personal sanitario. Así mismo, se pretende reflejar las actuaciones sanitarias durante dicho mes. El total de pacientes en la unidad fue de 90, realizándose la determinación PCR a todos, 37 (41,1%) dieron positivo a COVID-19, de estos 22 (59,4%) eran sintomáticos y 15 (40,5%) eran asintomáticos. De los pacientes positivos, 16 (43,2%) precisaron ingreso hospitalario y 6 (16,2%) fallecieron. Los pacientes fallecidos eran de mayor edad que los supervivientes. La muestra de profesionales sanitarios fue de 44, de los que 15 (34%) presentaron sintomatología. El servicio de Salud Laboral sólo determinó PCR a este grupo, obteniendo 4 profesionales (9%) PCR positivo, sin embargo tras considerar los criterios clínicos/radiológicos un total de 9 profesionales fueron diagnosticados como COVID-19 positivos, requiriendo 1 de ellos ingreso hospitalario. Conclusiones: se detectó una elevada prevalencia de COVID-19 positivo en los pacientes de la unidad de diálisis, donde destaca el elevado número de pacientes asintomáticos detectados mediante cribado PCR al total de los pacientes. Algunos profesionales presentaron algún tipo de sintomatología correspondiente con clínica COVID-19, pero se detectaron pocos casos con PCR positiva.

Introduction Patients on hemodialysis are at high-risk for complications derived from coronavirus disease-19 (COVID-19). The present analysis evaluated the impact of a booster vaccine dose and breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections on humoral immunity three months after the booster dose. Methods This is a multicentric and prospective study assessing IgG anti-Spike antibodies 6 and 9 months after initial SARS-CoV-2 vaccination in patients on hemodialysis that had also received a booster dose before the 6-month assessment (early booster) or between the 6- and 9-month assessments (late booster). The impact of breakthrough infections, type of vaccine, time from the booster and clinical variables were assessed. Results A total of 711 patients (67% male, 67 [20-89] years) were included. Of which, 545 (77%) received an early booster and the rest a late booster. At 6 months, 64 (9%) patients had negative anti-Spike antibody titers (3% of early booster and 29% of late booster patients, p = 0.001). At 9 months, 91% of patients with 6-month negative response had seroconverted and there were no differences in residual prevalence of negative humoral response between early and late booster patients (0.9% vs 0.6%, p = 0.693). During follow-up, 35 patients (5%) developed breakthrough SARS-CoV-2 infection. Antibody titers at 9 months were independently associated to mRNA-1273 booster (p = 0.001), lower time from booster (p = 0.043) and past breakthrough SARS-CoV-2 infection (p<0.001). Conclusions In hemodialysis patients, higher titers of anti-Spike antibodies at 9 months were associated to mRNA-1273 booster, lower time from booster and past breakthrough SARS-CoV-2 infection.

This is an open access article under the terms of the Creat ive Commo ns Attri butio n-NonCo mmerc ial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.