Background: Kidney transplant recipients are immunocompromised hosts of COVID-19 with a higher risk of infection and severe disease due to underlying CKD and long-term immunosuppression, thus vaccination against COVID is strongly recommended. However, studies indicate that transplant recipients mount lower antibody responses following vaccination compared with healthy individuals. Due to limited information on the outcomes of COVID-19 vaccination on transplant recipients, this study will examine the efficacy of vaccination in preventing severe to critical COVID in this immunocompromised population.

Objective: To determine the outcomes of kidney transplant recipients admitted for COVID-19 at the National Kidney and Transplant Institute and the impact of COVID-19 vaccination status on their survival.

Methods and Materials: A retrospective study of 131 kidney transplant recipients admitted for COVID-19 from March 2020 to December 2021. Descriptive statistics were used to summarize the clinical characteristics and outcomes of the participants.

Results: The median age was 51 years old with a male gender distribution of 54.5%. Chronic glomerulonephritis was the most common primary renal disease. Diabetes, hypertension, and cardiovascular disease were the most common co-morbidities. Patients belonging to the critical COVID group were observed to have older kidney allografts with a median age of 120 months. Among 131 kidney transplant recipients, 24.8% were fully vaccinated and 74.2% were either unvaccinated or partially vaccinated. Of the 32 patients in the vaccinated group, 3 were vaccinated with Astra Zeneca, 5 received Janssen, 7 from Moderna, 10 from Pfizer, 1 received Sputnik and 12 received Coronavac (Sinovac). Among the vaccinated group, those who received Moderna and Pfizer vaccines were observed to have moderate COVID-19 disease progression only with 57.1% from the Moderna group and 40% from the Pfizer group. Among patients who progressed to critical COVID-19, it was observed that a significant number of them came from the Coronavac group.

The need for oxygenation was observed in 64% of patients, of which 65.5% were unvaccinated. Acute kidney injury was reported in 43.5% of the overall population, 63.2% of which were observed in the unvaccinated group. Of the 16% who had graft loss during COVID-19 admission, 57.1% were unvaccinated. The incidence of death was lower among fully vaccinated than those in the partial and unvaccinated groups. Likewise, the probability of survival is highest among fully vaccinated than those partially vaccinated and unvaccinated. Renal graft biopsy on patients with COVID-19 has not been practiced at NKTI thus rendering rates of biopsy-proven acute rejection a limitation of the study.

Conclusion: Our experience shows that lack of COVID-19 vaccination among kidney transplant recipients demonstrates a higher rate of mortality associated with COVID-19.

Key words: COVID-19, renal transplantation, survival, Philippines.