Clustering Analysis Identified Distinct Clinical Phenotypes among Hemodialysis Patients in Their Immunological Response to the BNT162b2 mRNA Vaccine against SARS-CoV-2

<b>Background:</b> The 2019 coronavirus disease (COVID-19) pandemic induced a major health crisis worldwide, notably among end-stage kidney disease (ESKD) patients. Vaccination against SARS-CoV-2, especially with messenger RNA (mRNA) vaccines, is highly effective and reduces hospitalization and mortality in both the general and ESKD populations. Age and previous COVID-19 infection have been identified as major determinants of the vaccine response in both the general population and ESKD patients. <b>Methods:</b> To determine the specific phenotype of ESKD patients in relation to their vaccine response, a clustering approach was used in a cohort of 117 fully vaccinated patients. <b>Results:</b> Clustering revealed three distinct clinical phenotypes among hemodialysis patients in terms of immunological response. Two clusters, consisting of either women with a long dialysis history or male subjects with diabetes with a moderate history of dialysis, exhibited low levels of IgG anti-spike antibodies. The third cluster consisted of non-diabetic middle-aged men with a moderate dialysis vintage and a very good serological response to vaccination. <b>Conclusions:</b> These vaccinal phenotypes of dialysis patients are easily identifiable in current practice, allowing for differential serological follow-up and tailored booster SARS-CoV-2 vaccination.