INTRODUCTION: Since the pandemic of Coronavirus Disease 2019 (COVID-19) started from December 2019, remarkable numbers of infections and deaths associated with COVID-19 have been recorded worldwide. End-Stage Renal Disease (ESRD) patients on dialysis are particularly at high risk of infections due to impairments in the innate and adaptive immune system. Vaccination on dialysis patients (DP) still remains challenging, because of the variable response and low seroconversion rate compared with healthy controls (HC). Therefore, it is urgently necessary to establish a different vaccination strategy for DP, in terms of dose and administration time. METHODS: Here, we report an observational prospective cohort study in which the immunogenic efficacies of SARS-CoV-2 vaccine BNT162b2 on DP and HC were evaluated by absolute quantification of IgG levels in the blood. RESULTS: DP showed a delayed seroconversion after two vaccine doses, with a low absolute IgG levels compared to HC. While healthy populations reached complete seroconversion within 10 days from the administration of second dose, only 76% of DP were seropositive. After booster dose, DP strongly improved seroconversion rate as well as antibody levels, reaching 97% seropositivity and 50 times enhancement on antibody levels. DISCUSSION/CONCLUSION: These results prompt to suggest an additional vaccine dose in DP, reducing the interval of time from the second dose. Since few data are available on immune response in DP overtime after three vaccine doses currently, our study is among the first reports demonstrating the improved seropositivity and IgG levels in DP after booster vaccine dose.
The DiaCoVAb study in South Italy: immune response to Sars-CoV-2 vaccination in dialysis patients