SARS-CoV-2 Vaccine Effectiveness and Breakthrough Infections Among Patients Receiving Maintenance Dialysis.

RATIONALE & OBJECTIVE: SARS-CoV-2 vaccine effectiveness and immunogenicity threshold associated with protection against COVID-19 related hospitalization or death in the dialysis population is unknown. STUDY DESIGN: Retrospective, observational study. SETTING & PARTICIPANTS: Adult patients receiving maintenance dialysis through a national dialysis provider without COVID-19 history treated between February 1, 2021 and December 18, 2021 with follow up through January 17, 2022. PREDICTOR(S): SARS-CoV-2 vaccination status. OUTCOME(S): All SARS-CoV-2 infections, composite of hospitalization or death following COVID-19. ANALYTICAL APPROACH: Logistic regression was used to determine COVID-19 case rates and vaccine effectiveness. RESULTS: Of 16,213 patients receiving dialysis during the study period, 12,278 (76%) were fully vaccinated, 589 (4%) were partially vaccinated and 3,346 (21%) were unvaccinated by the end of follow-up. Of 1,225 COVID-19 cases identified, 550 (45%) occurred in unvaccinated patients, while 891 (73%) cases occurring during the Delta period. Between pre-Delta period and Delta periods vaccine effectiveness against a severe COVID-19 related event (hospitalization or death) was 84% and 70%, respectively. In the subset of 3,202 vaccinated patients with at least one anti-spike IgG assessment, lower anti-spike IgG levels were associated with higher case rates per 10,000 days and adjusted hazard ratios for both infection and COVID-related hospitalization or death. LIMITATIONS: Observational design, residual biases and confounding may exist. CONCLUSIONS: Among maintenance dialysis patients, SARS-CoV-2 vaccination was associated with a lower risk of COVID-19 diagnosis and associated hospitalization or death. Among vaccinated patients, low anti-spike IgG level is associated with worse COVID-19 related outcomes.

SARS-CoV-2 Infections among Vaccinated Patients on Maintenance Dialysis, January 1-August 31, 2021, United States.

Dialysis facilities voluntarily reported severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in vaccinated dialysis patients detected between January 1, 2021, and August 31, 2021, to the Centers for Disease Control and Prevention.Among 4087 patients reported, most were symptomatic, a third required hospitalization, and 9% died within 30 days of diagnosis.Monitoring SARS-CoV-2 infections and outcomes among vaccinated people on dialysis provides valuable insight into this population.

Immunogenicity of SARS-CoV-2 Vaccine in Dialysis.

BACKGROUND: Patients receiving maintenance dialysis represent a high-risk, immune-compromised population with 15%-25% COVID-19 mortality rate who were unrepresented in clinical trials of mRNA vaccines. METHODS: All patients receiving maintenance dialysis who received two doses of SARS-CoV-2 mRNA vaccines with antibody test results drawn ≥14 days after the second dose, as documented in the electronic health record through March 18, 2021, were included. Response was on the basis of levels of Ig-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike-antigen (seropositive ≥2 U/L) using an FDA-approved semiquantitative chemiluminescent assay (ADVIA Centaur XP/XPT COV2G). RESULTS: Among 186 patients on dialysis from 30 clinics in eight states tested 23±8 days after receiving two vaccine doses, there were 165 (88.7%) responders with 70% at maximum titer. There was no significant difference between BNT162b2/Pfizer (148 out of 168, 88.1%) and mRNA-1273/Moderna (17 out of 18, 94.4%), P=0.42. All 38 patients with COVID-19 history were responders, with 97% at maximum titer. Among patients without COVID-19, 127 out of 148 (85.8%) were responders, comparable between BNT162b2/Pfizer (113 out of 133) and mRNA-1273/Moderna (14 out of 15) vaccines (85.0% versus 93.3%, P=0.38). CONCLUSIONS: Most patients receiving maintenance dialysis responded after two doses of BNT162b2/Pfizer or mRNA-1273/Moderna vaccine, suggesting the short-term development of antispike antibody is good, giving hope that most of these patients who are vulnerable, once immunized, will be protected from COVID-19. Longer-term evaluation is needed to determine antibody titer durability and if booster dose(s) are warranted. Further research to evaluate the approach to patients without a serologic response is needed, including benefits of additional dose(s) or administration of alternate options.

Seroresponse to SARS-CoV-2 Vaccines among Maintenance Dialysis Patients over 6 Months.

BACKGROUND AND OBJECTIVES: Although most patients receiving maintenance dialysis exhibit initial seroresponse to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, concerns exist regarding the durability of this antibody response. This study evaluated seroresponse over time. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective cohort study included patients on maintenance dialysis, from a midsize national dialysis provider, who received a complete SARS-CoV-2 vaccine series and had at least one antibody titer checked after full vaccination. IgG spike antibodies (anti-spike IgG) titers were assessed monthly with routine laboratory tests after vaccination; the semiquantitative assay reported a range between zero and ≥20 Index. Descriptive analyses compared trends over time by history of coronavirus disease 2019 (COVID-19) and vaccine type. Time-to-event analyses examined the outcome of loss of seroresponse (anti-spike IgG <1 Index or development of COVID-19). Cox regression adjusted for additional clinical characteristics. RESULTS: Among 1870 patients receiving maintenance dialysis, 1569 had no prior COVID-19. Patients without prior COVID-19 had declining titers over time. Among 443 recipients of BNT162b2 (Pfizer), median (interquartile range) anti-spike IgG titer declined from ≥20 (5.89 to ≥20) in month 1 after full vaccination to 1.96 (0.60-5.88) by month 6. Among 778 recipients of mRNA-1273 (Moderna), anti-spike IgG titer declined from ≥20 (interquartile range, ≥20 to ≥20) in month 1 to 7.99 (2.61 to ≥20) by month 6. The 348 recipients of Ad26.COV2.S (Janssen) had a lower titer response than recipients of an mRNA vaccine over all time periods. In time-to-event analyses, recipients of Ad26.COV2.S and mRNA-1273 had the shortest and longest time to loss of seroresponse, respectively. The maximum titer reached in the first 2 months after full vaccination was associated with durability of the anti-spike IgG seroresponse; patients with anti-spike IgG titer 1-19.99 had a shorter time to loss of seroresponse compared with patients with anti-spike IgG titer ≥20 (hazard ratio, 15.5; 95% confidence interval, 11.7 to 20.7). CONCLUSIONS: Among patients receiving maintenance dialysis, vaccine-induced seroresponse wanes over time across vaccine types. Early titers after full vaccination are associated with the durability of seroresponse.

COVID-19 Among US Dialysis Patients: Risk Factors and Outcomes From a National Dialysis Provider.

RATIONALE & OBJECTIVE: During the coronavirus disease 2019 (COVID-19) pandemic, patients receiving maintenance dialysis are a highly vulnerable population due to their comorbidities and circumstances that limit physical distancing during treatment. This study sought to characterize the risk factors for and outcomes following COVID-19 in this population. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Maintenance dialysis patients in clinics of a midsize national dialysis provider that had at least 1 patient who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from February to June 2020. PREDICTORS: Demographics, dialysis characteristics, residence in a congregated setting, comorbid conditions, measurements of frailty, and use of selected medications. OUTCOMES: COVID-19, defined as having a positive SARS-CoV-2 test result, and all-cause mortality among those with COVID-19. ANALYTICAL APPROACH: Logistic regression analyses conducted to identify clinical characteristics associated with COVID-19 and risk factors associated with mortality among patients following COVID-19. RESULTS: 438 of 7948 (5.5%) maintenance dialysis patients developed COVID-19. Male sex, Black race, in-center dialysis (vs home dialysis), treatment at an urban clinic, residence in a congregate setting, and greater comorbidity were associated with contracting COVID-19. Odds of COVID-19 were 17-fold higher for those residing in a congregated setting (odds ratio [OR], 17.10 [95% CI, 13.51-21.54]). Of the 438 maintenance dialysis patients with COVID-19, 109 (24.9%) died. Older age, heart disease, and markers of frailty were associated with mortality. LIMITATIONS: No distinction was detected between symptomatic and asymptomatic SARS-CoV-2 positivity, with asymptomatic screening limited by testing capacity during this initial COVID-19 surge period. CONCLUSIONS: COVID-19 is common among patients receiving maintenance dialysis, particularly those residing in congregate settings. Among maintenance dialysis patients with COVID-19, mortality is high, exceeding 20%.