Real-world Evidence of COVID-19 Vaccines Effectiveness in Solid-organ Transplant Recipient Population in Colombia: A Study Nested in the Esperanza Cohort

Background. Solid-organ transplant recipients (SOTRs) have a higher risk of coronavirus disease 2019 (COVID-19) complications and death and a less powerful and lasting response to vaccines and to natural infection. In Colombia, this population was prioritized in the National Vaccination Plan against COVID-19 and received vaccines from different platforms. The aim of this study was to estimate the effectiveness of the complete vaccination schedule and of the vaccine booster for COVID-19 administered to SOTRs in Colombia. Methods. A nested-cohort was assembled within the population-based ESPERANZA cohort and included the subset of 16 y and older SOTRs (n = 6963); the follow-up period spanned March 11, 2021, to May 11, 2022. The vaccine effectiveness was estimated with Cox proportional-hazards models so that the overall effectiveness of the complete vaccination schedule, the vaccine booster, each used vaccine, and the homologous and heterologous schedules were estimated, adjusting by the main confounders. Results. The overall effectiveness of being fully vaccinated was 73.7% (95% confidence interval [CI], 68.9%-77.0%) to prevent COVID-19 infection, 83.7% (95% CI, 78.7%-87.5%) to prevent hospitalization, and 92.1% (95% CI, 88.8%-94.4%) to prevent death due to COVID-19. Similarly, the effectiveness of the vaccine booster was 76.7% (95% CI, 70.6%-81.5%), 86.9% (95% CI, 79.4%-91.6%), and 94.5% (95% CI, 89.8%-97.1%) to prevent confirmed COVID-19 infection, hospitalization, and death due to COVID-19, respectively. In both cases, there were no statistically significant differences across age groups. Conclusions. Findings from this work show a high protection of vaccination against infection, hospitalization, and death due to COVID-19 in SOTRs, which increases with the vaccine booster.