#5916 ANALYSIS OF SARS-COV2 INFECTION AND COVID-19 VACCINATION IN TWO DIAVERUM CLINICS IN NORTH MACEDONIA
Authors: Petrova Kristina , Ivanovska Ditka , Misovska Nadica , Grozdanova Eleonora , Nedelkoska Mence , Krzovska Marija , Medarova-Stojkovska Zorica , Kjulibrk-Nedelkovska Maja , Ilievski Stefan , Roglev Boris 
Published: June 2023

Abstract

Background and Aims
Hemodialysis patients as a separate group of immunosuppressive patients are at highest risk of severe clinical complications and death caused by infection with SARS-CoV-2 virus. With the introduction of COVID-19 vaccination in hemodialysis patients, the situation has changed significantly. The aim of the study was to analyze the difference in morbidity and mortality between two groups of hemodialysis patients, vaccinated and unvaccinated for Covid-19 in two Diaverum Clinics.

Method
The study is based on analysis of the data of hemodialysis patients in two Diaverum clinics during the period from April 2020, when the first case of SARS-CoV-2 virus was detected in Diaverum Kochani Clinic, to August 2022, when the last case of SARS-CoV-2 virus was detected in both clinics. Analytical data are taken from IRIMS database used only by Diaverum Clinics worldwide.

Results
During the period of observation, a total number of 214 hemodialysis patients were treated in both Diaverum Clinics. Regarding gender distribution 63% are males and 37% are females. From the total number of patients in both clinics, 67% (143) were vaccinated with two or three doses of the COVID 19 vaccines, while the remaining 33% (71) patients were COVID-19 unvaccinated. The majority of the patients (67%) were vaccinated with Chinese vaccine Sinopharm; 19% with Sinovac; 7% with Astra Zeneca; 7% with Pfizer BioNTech (the vaccines that were available in that period in our country). In 2020 a total of 28 COVID infection occurred in both clinics, all of them were unvaccinated patients; 16 of them were hospitalized and 9 of them died. Hospitalization rate was 57% and mortality rate 32% among the positive patients. In 2021 a total of 35 COVID infections were registered, 18 were hospitalized (unvaccinated 61% vs 39% vaccinated). 26% (9) of the positive patients died, 6 were unvaccinated and 3 were vaccinated with 2 doses. Hospitalization rate was 51% and mortality rate 26%. In 2022 a total of 43 COVID infections occurred, only 4 were hospitalized and only 1 patient died; hospitalization rate 9%; mortality rate 2,3%. When the whole study period was analyzed, the infection rate between the vaccinated and unvaccinated patients in both clinics was statistically not significant, 51% vs 46,5%, p = 0,5634 (Fisher exact two-tailed test). But, when the hospitalization rate was compared between vaccinated and unvaccinated patients, 12,3% vs 84,8%, the difference was highly statistically significant (p = 0,0001). When death rate was compared between the two groups, the difference was also highly statistically significant, 5,5% vs 45,4% in the unvaccinated group (p = 0,0001).

Conclusion
The results of our study showed no difference in the infection rate between vaccinated and unvaccinated patients, but they confirmed high level of protection from hospitalization and mortality in vaccinated patients.