Comparison of antibody response to two different mRNA Covid-19 vaccines in patients on hemodialysis

Introduction: In hemodialysis patients, coronavirus disease 2019 is associated with high morbidity and mortality. Aim of the study was to evaluate the antibody level against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients treated with two different mRNA-based vaccines, in a multicenter survey.

Patients and methods: Since April 2020, in the 5 participating Centers, periodic screening of all patients with PCR testing has been performed every 2 weeks. The study included two cohorts of patients on maintenance hemodialysis treated with the BNT162b2 or with the mRNA-1273 Covid-19 vaccine. The tests for antibodies against the receptor-binding domain was performed by the anti-SARS-CoV-2 S enzyme immunoassay (Roche Elecsys).

Results: Of the 398 included patients, 303 received the BNT162b2 and 95 the mRNA-1273 vaccine. In patients without previous infection, the median levels of anti-S antibodies were 297 U/mL and 1,032 U/mL for those treated with BNT162b2 or mRNA-1273, respectively (p < 0.001). In patients with previous infection, the median levels of SARS-CoV-2 anti-S antibodies were 7,516 U/mL and 17,495 U/mL for those treated with BNT162b2 or mRNA-1273, respectively (p = 0.005). The Charlson comorbidity index (CCI) was significantly associated with protective levels of anti-spike IgG, with 3.6% of low- or non-responders having a CCI of 2-4 versus 18.9% in those with a CCI of 8 or more. The adjusted OR of developing a sufficient antibody level between the two vaccines was 3.91 (p = 0.0766) in favor of mRNA-1273.

Conclusions: Both of the evaluated mRNA-based vaccines for SARS-CoV-2 showed good efficacy. Preliminary data may data suggest a higher antibody response to the mRNA-1273 vaccine.