EFFECTIVENESS OF SARS-COV-2 VACCINATION IN PERITONEAL DIALYSIS PATIENTS

ABSTRACT

BACKGROUND AND AIMS: Chronic kidney disease (CKD) patients, especially those on renal replacement therapy, have a higher risk of infection and worse clinical outcomes after coronavirus disease 2019 (COVID-19) than the general population. Thus, this population must be promptly immunized against COVID-19. We aimed to assess the humoral response after two doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) vaccine in peritoneal dialysis (PD) patients. We also aimed to identify potential factors associated with vaccine response and the prevalence of COVID-19 in a PD unit. METHOD: We conducted a single-center, retrospective study to evaluate the immunogenicity in terms of antibody response after COVID-19 vaccination. Three types of vaccine [BNT162b2 messenger RNA vaccine (Pfizer-BioNTech), messenger RNA-1273 (Moderna) and ChadOx1 nCoV-19/AZD1222 (AstraZeneca)] were administered in the PD unit. The detection of anti-spike IgG antibodies (with a cutoff of 0.8 U/mL) was done at least after 21 days of the two vaccine doses. We also evaluated the presence of COVID-19 infections, hospital admissions (including in intensive care unit) and deaths. RESULTS: This study enrolled 70 prevalent patients. We excluded patients with only one vaccine dose (n = 4), those who did not consent to the collection (n = 5) or were vaccinated before starting PD (n = 11). Among the 50 patients included, the mean age was 59 ± 15 years, 60% were male and the dialysis vintage was 22.1 (IQR 6-34.3) months. Six (12%) patients were receiving immunosuppressive therapy and 16 (32%) had diabetes. The mean interval between administration of the second vaccine dose and antibodies evaluation was 7.2 ± 0.7 months. Overall, after two doses, there was a significant increase in antibody level, with median of 1495 (IQR 37.8- 546.8) U/mL. Only two (4%) patients did not increase their antibody level (remained seronegative). History of immunosuppressive therapy was associated with no response after two doses (91.7% versus 8.3%, P = 0.012). There were two COVID-19 infections after the complete vaccination, with mild symptoms (one with hospital admission). Furthermore, there were no intensive care unit admissions or deaths. CONCLUSION: We found that immunization against COVID-19 was effective in generating an overall humoral response and in preventing severe disease in CKD patients on PD, which emphasizes the importance of the vaccination against COVID-19 in this population. These results also suggest the impact of the immunosuppressive therapy on vaccine response in PD patients.