Efficacy of the BNT162b2 mRNA COVID-19 vaccine in a haemodialysis cohort

Abstract

Nephrologists call for priority access to coronavirus disease 2019 (COVID-19) vaccination in patients receiving in-centre haemodialysis [1] for two main reasons: a very high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection compared with the general population (5–16 times more likely [2] because they travel to their dialysis centre three times a week and are surrounded by other patients and caregivers) and also a particular high mortality rate (close to 20%) when infected by SARS-CoV-2 [3]. Our team is taking care of 470 in-centre haemodialysis patients in Marseille and its surroundings, a region severely affected by COVID-19. As soon as vaccination was prioritized for our patients, we proceeded to a large-scale campaign as of 18 January 2021, when the first injections were administered. Nevertheless, a major downside is vaccine hyporesponsiveness among such immune-compromised patients, who often show disappointing seroconversion rates (e.g. a 44% rate following a double-dose vaccination schedule for hepatitis B [4]). In this context and given the lack of data on COVID-19 vaccination in dialysis, we decided to evaluate the vaccine response of our patients by serology testing in order to optimize their future management. We proposed the COVID-19 vaccination—two injections 3 weeks apart of the BNT162b2 mRNA COVID-19 vaccine—to all our in-centre haemodialysis patients. The exclusion criteria were a lack of consent or a SARS-CoV-2 infection less than 3 months ago. The patients were vaccinated in their dialysis centre (the majority during their dialysis session). Vaccination efficacy was assessed 1 month after the second injection by quantifying antibodies directed against the Spike protein using the Elecsys® Anti SARS-CoV-2 S enzyme immunoassay (which presents a high correlation with neutralizing antibodies). As of early March, 70% of our cohort (326 patients) had received the two injections (3 weeks apart) of the BNT162b2 mRNA COVID-19 vaccine. Vaccine tolerability was excellent, with no serious adverse event in the overall cohort. The first results, regarding 244 patients, show a very high response rate: 91% present a positive antibody titer (with a cut-off fixed at 15 U/mL for the Elecsys® Anti SARS-CoV-2 S test). The baseline characteristics of the patients and their immune response are shown in Tables 1 and 2. Patient characteristics and immune response after two doses of the BNT162b2 mRNA COVID-19 vaccine Interquartile range (IQR). With ongoing treatment. Pancreatic graft. BMI, body mass index. Demographic and clinical characteristics of patients stratified by immune response Descriptive statistics included the percentages for categorical variables and the median [interquartile range (IQR)] for continuous variables according to the distribution. Comparisons between the two groups according to the presence or absence of a significant antibody level for continuous variables were made using the Student’s t-test or the Mann–Whitney test, according to the variable distribution. Comparisons between the two groups for categorical variables were made using the Pearson’s chi-square test or Fisher’s exact test. A P-value <0.05 was considered significant (shown in bold). The statistical analysis was conducted using R version 3.6.0 R Development Core Team (2019). BMI, body mass index. Older patients were less likely to present an antibody response. There was also no response to vaccination among all the patients undergoing chemotherapy (3/3) or under immunosuppression (1/1). These results go far beyond what is usually seen with other vaccines in this hyporesponsive population, with a 91% antibody positivity rate, with 60% of the patients presenting an antibody level >200 U/mL correlating to maximal neutralizing capacity in the neutralization assays for the Elecsys® Anti SARS-CoV-2 S test. However, some of our patients showed a rather weak response, and a recent study [5] reported lower antibody levels in dialysis patients compared with the general population. The consequences may be a lower vaccine efficacy and a shorter period of immunoprotection. It is therefore necessary to consider reinforced vaccination schedules. Nevertheless, in parallel to these biological results, we have witnessed a spectacular decrease in new case occurrences as of mid-February (3 weeks after the first injections) in our dialysis centres. This clinical and biological response to a mRNA COVID-19 vaccination among a highly vulnerable population is extremely promising. Studies to assess vaccine efficacy in this population in the real-word setting are needed. The authors declare that the results presented in this paper have not been published previously in whole or part. None of the authors presents a conflict of interest.

Topics & Concepts