Real-World Effectiveness and Immunogenicity of BNT162b2 and mRNA-1273 SARS-CoV-2 Vaccines in Patients on Hemodialysis
Authors: Sibbel Scott , McKeon Katherine , Luo Jiacong , Wendt Karl , Walker Adam G. , Kelley Tara , Lazar Rachael , Zywno Meredith L. , Connaire Jeffrey J. , Tentori Francesca , Young Amy , Brunelli Steven M. 
Published: November 2021

Significance Statement
Because of multiple comorbidities and demographic characteristics, patients on dialysis are at high risk for COVID-19–related morbidity and mortality. However, such patients were not included in SARS-CoV-2 vaccine trials. To study the real-world effectiveness and immunogenicity of two mRNA SARS-CoV-2 vaccines (BNT162b2 and mRNA-1273) in a large, representative population of in-center hemodialysis patients in the United States, the authors conducted a retrospective, observational study to estimate these vaccines’ clinical effectiveness and ability to induce antibody responses. Their use was associated with a 73%–78% lower risk of COVID-19 infection and significantly lower risks of hospitalization or death. Nearly all vaccinated patients generated antibodies. These findings provide support for the use of these vaccines in patients on hemodialysis.

Background
Patients on hemodialysis have an elevated risk for COVID-19 but were not included in efficacy trials of SARS-CoV-2 vaccines.

Methods
We conducted a retrospective, observational study to estimate the real-world effectiveness and immunogenicity of two mRNA SARS-CoV-2 vaccines in a large, representative population of adult hemodialysis patients in the United States. In separate, parallel analyses, patients who began a vaccination series with BNT162b2 or mRNA-1273 in January and February 2021 were matched with unvaccinated patients and risk for outcomes were compared for days 1-21, 22-42, and ≥43 after first dose. In a subset of consented patients, blood samples were collected approximately 28 days after the second dose and anti–SARS-CoV-2 immunoglobulin G was measured.

Results
A total of 12,169 patients received the BNT162b2 vaccine (matched with 44,377 unvaccinated controls); 23,037 patients received the mRNA-1273 vaccine (matched with 63,243 unvaccinated controls). Compared with controls, vaccinated patients’ risk of being diagnosed with COVID-19 postvaccination became progressively lower during the study period (hazard ratio and 95% confidence interval for BNT162b2 was 0.21 [0.13, 0.35] and for mRNA-1273 was 0.27 [0.17, 0.42] for days ≥43). After a COVID-19 diagnosis, vaccinated patients were significantly less likely than unvaccinated patients to be hospitalized (for BNT162b2, 28.0% versus 43.4%; for mRNA-1273, 37.2% versus 45.6%) and significantly less likely to die (for BNT162b2, 4.0% versus 12.1%; for mRNA-1273, 5.6% versus 14.5%). Antibodies were detected in 98.1% (309/315) and 96.0% (308/321) of BNT162b2 and mRNA-1273 patients, respectively.

Conclusions
In patients on hemodialysis, vaccination with BNT162b2 or mRNA-1273 was associated with a lower risk of COVID-19 diagnosis and lower risk of hospitalization or death among those diagnosed with COVID-19. SARS-CoV-2 antibodies were detected in nearly all patients after vaccination. These findings support the use of these vaccines in this population.