ABSTRACT
BackgroundSARS-CoV-2 vaccine effectiveness during the Delta period and immunogenicity threshold associated with protection against COVID-19 related hospitalization or death in the dialysis population is unknown. MethodsA retrospective, observational study assessed SARS-CoV-2 vaccine effectiveness and immunogenicity threshold in all adult maintenance dialysis patients without COVID-19 history treated between February 1 and October 2, 2021. All COVID-19 infections, composite of hospitalization or death following COVID-19 and available SARS-CoV-2 anti-spike immunoglobulin (Ig) G values were extracted from electronic medical record. COVID-19 cases per 10,000 days at risk and vaccine effectiveness during pre-Delta and Delta periods were determined. ResultsOf 15,718 patients receiving dialysis during the study period, 11,191 (71%) were fully vaccinated, 733 (5%) were partially vaccinated and 3,794 (24%) were unvaccinated. 967 COVID-19 were cases identified: 511 (53%) occurred in unvaccinated patients and 579 (60%) occurred during the Delta period. COVID-19 related hospitalization or death was less likely among vaccinated versus unvaccinated patients for all vaccines (adjusted HR 0.19 [0.12, 0.30]) and for BNT162b2/Pfizer, mRNA-1273/Moderna, and Ad26.COV2.S/Janssen (adjusted HR=0.25 [0.16, 0.40], 0.14 [0.08, 0.22], and 0.34 [0.17, 0.68] respectively). Among those with anti-spike IgG levels, those with IgG level [≥] 7 had significantly lower risk of a COVID-19 diagnosis (HR=0.25 [0.15, 0.42]) and none experienced a COVID-related hospitalization or death. ConclusionsAmong 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. Significance StatementSARS-CoV-2 vaccine effectiveness and association between antibody levels and clinical outcomes in maintenance dialysis patients is not known. Between February 1 and October 2, 2021, vaccine effectiveness was 85% against COVID-19 infection and 81% against composite of COVID-related hospitalization or death. COVID-19 case rates and severe outcomes were higher during the Delta dominant period (June 27-October 2, 2021). Increasing time (weeks) since full vaccination status was associated with increased risk for COVID-19 related hospitalization or death. Anti-spike IgG level [≥] 7 had lower risk of a COVID-19 diagnosis and no COVID-related hospitalization or death. Our findings supports utilization of SARS-CoV-2 vaccination and suggests that monitoring SARS-CoV-2 antibody levels and administering additional vaccine doses to maintain adequate immunity will be beneficial.
ABSTRACT
BackgroundPatients 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. MethodAll 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(R) XP/XPT COV2G). ResultsAmong 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. ConclusionMost 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. SignificanceIn 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.
