A Retrospective Study Comparing Mortality Rates between Vaccinated
and Unvaccinated Kidney Transplant Recipients
Authors: Fayyaz Anaam , Pozzerle Judy , Antony Suresh J. 
Published: December 2023

Background:
With the emergence of vaccines for COVID-19, mortality and severity of
disease have decreased. However, patients with certain comorbidities, such as immunosuppression,
CKD, and renal transplant, still have higher mortality rates as compared to the general population.
Current data suggests that the risk of developing COVID-19 among transplant patients was reported
to be about 5%, which is significantly higher than the risk rate of 0.3% in the general population.
Studies utilizing larger sample sizes (i.e., multiple cohorts, sites, hospitals) comparing COVID-19
outcomes among renal transplant patients with a control group are lacking.

background:
Coronaviruses belong to a family of Viruses that can cause range of illnesses ranging from the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) (1,2). In 2019 a new Coronavirus was identified and was named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Severe Acute Respiratory Syndrome Coronavirus-2 (SARSCoV-2) which belongs to the genus beta-CoV which also includes Severe Acute Respiratory Syndrome CoV (SARS-CoV), and Middle Eastern Respiratory Syndrome CoV (MERS-CoV) (2). World Health Organization (WHO) later announced an alternative name for the disease caused by SARS-CoV-2: CoV disease (COVID-19) (2). As of May 25, 2022 an estimated 524,339,768 cases of COVID-19 were reported to World health organization including 6,281,260 deaths related to COVID globally. However, the disease affects patients with certain risk factors disproportionally. Recent data has shown chronic comorbidities, such as acute kidney injury, COPD, diabetes, hypertension, CVD, cancer, increased D-dimer, along with demographic variables such as male gender, older age, current smoker, and obesity are clinical risk factors for a fatal outcome associated with coronavirus [3]. With the emergence of COVID-19 vaccines, severity and mortality of the disease decreased and has contributed in controlling the pandemic that has claimed so many lives across the globe (4). Even with the emergence of vaccine, the disease continued to claim a disproportionate number of lives, particularly among immunocompromised individuals

Objective:
The purpose of this descriptive study was to compare the mortality rate between vaccinated
and unvaccinated kidney transplant recipients.

objective:
The purpose of this study is to provide a descriptive overview of clinical outcomes between vaccinated and unvaccinated kidney transplant recipients in a single transplant center in West Texas

Methods:
Participants were recruited at a community-based transplant clinic in West Texas. Results
Among the group of participants who tested positive for COVID-19 between 2020 and 2022, higher
mortality rates and longer hospital stays were noted among those unvaccinated (72% unvaccinated
had greater than 5-day length of stay vs. 33% vaccinated).

method:
Retrospective Data was collected from Kidney Transplant Clinic at a Medical Center located in El Paso, Texas. Data was gathered between January 2020 and January 2022 from the transplant database. Data was extrapolated for demographics including age, race, gender. Other data included vaccinated vs. unvaccinated status, comorbidities, immunosuppression status, outcomes such as length of stay in the hospital and mortality rate. A total of 38 patients were included in the study between the year 2020 and 2022. In cases where the patient died, missing data was collected from the next of kin. Inclusion criteria included aged 18 and older, being a kidney transplant recipient (deceased and living) and had a current functioning transplanted kidney. We included all patients who tested positive for COVID-19 during January 2020 to December 2022. Patient whose data could not be obtained since they were deceased and/or did not have next of kin were excluded from the study. Patients were also excluded from the study if their missing data could not be obtained or validated by patient or next of kin.

Conclusion:
Our study suggests that vaccination against COVID-19 decreases mortality rates in
kidney transplant recipients.

result:
Among the 38 patients included in the data set 94.7% identified as Hispanic vs 5.2% were non-Hispanics and 71% were male vs 28.9% were females. The majority of the patients were vaccinated (71% vs 28.9% non-vaccinated). The data also showed higher rates of death in Unvaccinated population as opposed to vaccinated patients (90.9% vs 14.8%). 72% of unvaccinated transplant recipients had a length of stay greater than 5 days compared to 33% of vaccinated patients. All of the patients evaluated in the cohort had two or more comorbidities such as HTN, atrial fibrillation and DM2 (100%). Among patients included in the cohort 84.2% were deceased renal transplant recipients while 15.7% living renal transplant recipients. Furthermore, increased mortality rates were seen among patients treated with higher induction doses (greater than 350mg). A total of 20 patients in the cohort received greater than 350 mg of induction doses out of which 9 were unvaccinated (45%) and 12 were vaccinated (60%). Out of the 9 unvaccinated patients 8 patients died (88%) while 1 patient survived (11.1).
Respiratory failure was the main cause of death among patients that passed away, regardless of vaccine status (90.9% Vaccinated vs 14.8% unvaccinated).

conclusion:
Large phase 3 clinical trials are still currently underway worldwide to study the effects of vaccine on transplant patient. Our study suggests that vaccination against COVID 19 decreases mortality rates in Kidney Transplant recipient. Our retrospective study compared mortality rates between vaccinated and unvaccinated Kidney transplant recipients in a small clinic setting. It is important to have a large prospective double-blind study on the use of vaccinations in renal transplant recipients would be useful to study the effectiveness on this population.