Seroresponse to Inactivated and Recombinant Influenza Vaccines Among Maintenance Hemodialysis Patients.

RATIONALE & OBJECTIVE: High-dose influenza vaccine provides better protection against influenza infection in older adults than standard-dose vaccine. We compared vaccine seroresponse among hemodialysis patients over a period of 4 months after administration of high-dose trivalent inactivated (HD-IIV3), standard-dose quadrivalent inactivated (SD-IIV4), or quadrivalent recombinant quadrivalent (RIV4) influenza vaccine. STUDY DESIGN: Prospective observational study. SETTING & PARTICIPANTS: Patients at 4 hemodialysis clinics who received influenza vaccine. EXPOSURE: Type of influenza vaccine. OUTCOME: Hemagglutination inhibition (HI) titers were measured at baseline and at 1, 2, 3, and 4 months after vaccination. The primary outcome was seroprotection rates at HI titers of at least 1:40 and at least 1:160 (antibody levels providing protection from infection in approximately 50% and 95% of immunocompetent individuals, respectively) at 1, 2, 3, and 4 months after vaccination. ANALYTICAL APPROACH: We calculated geometric mean titer as well as seroprotection and seroconversion rates. Adjusted generalized linear models with additional trend analyses were performed to evaluate the association between vaccine type and outcomes. RESULTS: 254 hemodialysis patients were vaccinated against influenza with HD-IIV3 (n = 141), SD-IIV4 (n = 36), or RIV4 (n = 77). A robust initial seroresponse to influenza A strains was observed after all 3 vaccines. Geometric mean titer and seroprotection (HI titer ≥1:160) rates against influenza A strains were higher and more sustained with HD-IIV3 than SD-IIV4 or RIV4. More than 80% of patients vaccinated with HD-IIV3 were seroprotected (HI titer ≥1:160) at month 4 (P < 0.001), whereas, among patients vaccinated with SD-IIV4 or RIV4, seroprotection rates were similar to those at baseline. Seroprotection rates were lower against B strains for all vaccines. LIMITATIONS: Because of the use of observational data, bias from unmeasured confounders may exist. Some age subgroups were small in number. Clinical outcome data were not available. CONCLUSIONS: Hemodialysis patients exhibited high seroprotection rates after all 3 influenza vaccines. The seroresponse waned more slowly with HD-IIV3 compared with SD-IIV4 and RIV4 vaccines.

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.

Ergocalciferol Supplementation in Hemodialysis Patients With Vitamin D Deficiency: A Randomized Clinical Trial.

Locally produced 1,25-dihydroxyvitamin D3 may have pleiotropic effects outside of bone. Experimental and observational studies suggest that nutritional vitamin D may enhance erythropoiesis in settings of 25-hydroxy vitamin D (25(OH)D) deficiency. We conducted a double-blind, placebo-controlled, randomized clinical trial to assess the effects of supplementation with ergocalciferol on epoetin utilization and other secondary outcomes in patients on hemodialysis with serum 25(OH)D <30 ng/ml. In all, 276 patients were randomized to 6 months of ergocalciferol or placebo. Mean±SD serum 25(OH)D increased from 16.0±5.9 ng/ml at baseline to 39.2±14.9 ng/ml in the ergocalciferol arm and did not change (16.9±6.4 ng/ml and 17.5±7.4 ng/ml, respectively) in the placebo arm. There was no significant change in epoetin dose over 6 months in the ergocalciferol or placebo arms (geometric mean rate 0.98 [95% confidence interval (95% CI), 0.94 to 1.02] versus 0.99 [95% CI, 0.95 to 1.03], respectively) and no difference across arms (P=0.78). No change occurred in serum calcium, phosphorus, intact parathyroid hormone, or C-reactive protein levels, cinacalcet use, or phosphate binder or calcitriol dose in either study arm. Rates of all-cause, cardiovascular, and infection-related hospitalizations did not differ by study arm, although statistical power was limited for these outcomes. In conclusion, 6 months of supplementation with ergocalciferol increased serum 25(OH)D levels in patients on hemodialysis with vitamin D insufficiency or deficiency, but had no effect on epoetin utilization or secondary biochemical and clinical outcomes.

Immunogenicity of SARS-CoV-2 Vaccine in Dialysis.

BACKGROUND: Patients receiving maintenance dialysis represent a high risk, immune-compromised population with 15-25% COVID mortality rate who were unrepresented in clinical trials evaluated for mRNA vaccines' emergency use authorization. METHOD: All patients receiving maintenance dialysis that 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. We report seroresponse based on levels of immunoglobulin-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike antigen (seropositive ≥2) using FDA-approved semi-quantitative chemiluminescent assay (ADVIA Centaur® XP/XPT COV2G). RESULTS: Among 186 dialysis patients from 32 clinics in 8 states tested 23±8 days after receiving 2 vaccine doses, mean age was 68±12 years, with 47% women, 21% Black, 26% residents in long-term care facilities and 97% undergoing in-center hemodialysis. Overall seropositive rate was 165/186 (88.7%) with 70% at maximum titer and with no significant difference in seropositivity between BNT162b2/Pfizer (N=148) and mRNA-1273/Moderna (N=18) vaccines (88.1% vs. 94.4%, p=0.42). Among patients with COVID-19 history, seropositive rate was 38/38 (100%) with 97% at maximum titer. CONCLUSION: Most patients receiving maintenance dialysis were seropositive after two doses of BNT162b2/Pfizer or mRNA-1273/Moderna vaccine. Early evidence suggests that vaccinated dialysis patients with prior COVID-19 develop robust antibody response. These results support an equitable and aggressive vaccination strategy for eligible dialysis patients, regardless of age, sex, race, ethnicity, or disability, to prevent the extremely high morbidity and mortality associated with COVID-19 in this high risk population. SIGNIFICANCE: In this retrospective observational evaluation of SARS-CoV-2 mRNA vaccine response defined by detectable levels of immunoglobulin-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike antigen of ≥2 in serum of patients receiving maintenance dialysis, 165/186 (88.7%) were found to be seropositive (with 70% at maximum titer) at least 14 days after completing the second dose. No significant differences were observed by race or other subgroup or by vaccine manufacturer. Therefore, an equitable and aggressive vaccination strategy for all eligible maintenance dialysis patients, regardless of age, sex, race, ethnicity, or disability, is warranted to prevent the extremely high morbidity and mortality associated with COVID-19 in this high risk population.