Introduction: Patients on the solid organ transplant waiting list may be at increased risk of severe acute respiratory syndrome and death from COVID-19. Likewise, there is also a risk when transplanting a patient during the pandemic. The balance between the risks of transplanting over the risks of remaining on the waiting list in periods of high viral circulation of COVID-19, as well as the impact of vaccination, has not been studied in our country. The objective of this study was to determine the incidence of COVID-19 infection in patients on the waiting list for solid organs during the pandemic in Argentina, to compare the mortality from COVID-19 in patients on the waiting list vs. transplant patients, and the effect of vaccination on mortality.

Methods: This study was conducted using a national cohort study. The main source was the Argentine Information Management and Registration System (SINTRA). Three time periods were analyzed: 03/31/20-02/28/21, 03/01/21-11/30/21 and 12/01/2-02/28/22. Mortality rate, prognostic factors and evolution were analyzed by multivariate analysis. For the analysis of the impact of vaccination, it was considered vaccinated if the patient received at least 2 doses.

Results: During the 3 periods analyzed, 10,017 recipients on the waiting list for solid organs were confirmed with COVID-19. The mortality rate was 24% (928/3882); 18% (601/3,332) and 3% (78/2,803) for each period, respectively. The mortality rate in transplant patients was: 20% (310/1,549); 20% (384/1,892) and 3% (56/1,883), for the same periods analyzed. Higher mortality is observed in patients on the waiting list at the first peak of the pandemic (p=0.02). The vaccination rate was 57% and 74% in the 2nd and 3rd periods, respectively. Mortality according to the organ waiting list by period was: lung (13%-24%-13%), heart (19%-19%-5%), kidney (24%-18%-2%) and liver (24% - 18%-3%), kidney-pancreas (26%-17%-4%). In the multivariate analysis, the probability of death in waiting list patients was associated with age over 56 years (OR 1.6, 95% CI 1.4-1.9), hospitalization (OR 5.7, CI 4.8-6.6), admission to intensive care (OR 2.8 CI 2.1-3.8), and mechanical ventilation requirement (OR 13.7, 95% CI 8.4-22.3) . Vaccination was a protective factor against mortality (OR 0.04, 95% CI 0.03-0.05).

Conclusion: In Argentina, in the first period of the pandemic, a worse evolution of COVID-19 was observed in recipients on the waiting list for solid organ transplants compared to transplant patients. Mortality decreased mainly in the third period mainly due to vaccination and the optimization of prevention and treatment measures for COVID-19.