PROGNOSTIC FACTORS OF SEROLOGICAL RESPONSE TO THE SARS-COV 2 VACCINE IN PERITONEAL DIALYSIS: OUR EXPERIENCE

ABSTRACT

BACKGROUND AND AIMS: The severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) pandemic has had a massive impact in health systems worldwide, taking an important toll on dialysis patients as they are more comorbid, have higher mortality and an impaired immune system. Vaccines against SARS-Cov-2 proved to reduce mortality and hospitalization, but serological response in the dialysis population is weaker. Therefore, predictors of response would be useful to assess their level of protection and evaluate the need for further booster doses of the vaccine. METHOD:-We retrospectively analysed all peritoneal dialysis (PD) patients fully vaccinated (two doses) in our PD Unit between February and June 2021.-Clinical data, vaccine brand and anti SARS-Cov-2 IgG antibodies (Ab) measured by enzyme immunoassay were recorded.-The linear correlation between Ab level and all other variables was analysed using the Pearson correlation coefficient. RESULTS:-In the study period, 22 of 32 prevalent patients were fully vaccinated with two vaccine doses, 70.8% Moderna, 20.8% Pfizer/BioNTech and 8.3% AstraZeneca. A total of 50% were male and 36.4% had diabetes mellitus, with mean age 61.4 ± 12.3 years. Median time on PD was 15.6 months (IQR 4.9-25.1). Up to 22.7% were on immunosuppression (IS) after a kidney graft dysfunction (prednisolone, tacrolimus or both) and 22.7% had a previous diagnosis of coronavirus disease (COVID).-A total of 072.7% had an immediate minor adverse event after the second dose of the vaccine, mostly headache/malaise (31.8%) and puncture site pain (22.7%).-Ab levels were significantly higher in those patients with previous COVID (r = 0.452;P = 0.035). Male gender and Moderna vaccine had a positive correlation with higher Ab titers, although not statistically significant (r = 0.401, P = 0.064 and r = 0.215, P = 0.337, respectively). Those with longer duration of PD treatment before vaccination had a weaker serological response (r = -0.228, P = 0.307). Ab levels did not correlate with age (r = -0.046, P = 0.837), diabetes (r = -0.121, P = 0.600) or IS medications (r = -0.070, P = 0.756).-Shows Ab levels at 7.4 ± 4 weeks after the second dose CONCLUSION: In our experience, PD patients have an adequate serological response to the SARS-Cov-2 vaccines, being previous COVID exposure the main predictor of a good response. Conversely, longer duration of PD treatment was a prognostic factor of seroconversion failure. We believe this should be kept in mind to assess the need for booster vaccination doses in those patients.