Efficacy and safety of COVID-19 vaccination in solid organ transplant recipients: A systematic review and network meta-analysis

The impact of COVID-19 vaccination on clinical outcomes in solid organ transplant (SOT) recipients remains unclear. This systematic review and network meta-analysis sought to assess the efficacy and safety of COVID-19 vaccination in SOT recipients. We searched 6 databases from inception to March 1, 2024 for randomized controlled trials (RCTs) and observational studies evaluating different COVID-19 vaccination strategies in SOT recipients. Based on patient-important outcomes, we performed frequentist random-effects pairwise meta-analyses and network meta-analyses, separating RCTs and nonrandomized evidence, and used the Grading of Recommendation, Assessment, Development, and Evaluation approach to assess our certainty in the evidence. We included 6 RCTs (N = 814) and 43 observational studies (N = 125 199). Overall, there is a paucity of randomized evidence evaluating COVID-19 vaccines in SOT recipients. The nonrandomized evidence evaluating COVID-19 vaccination strategies patient-important outcomes, including COVID-19 infection, mortality, hospitalization, ICU admission, and rejection, demonstrated low to very low certainty due to the included studies' risk of bias. Throughout the COVID-19 pandemic, clinicians and SOT recipients worked with minimal, very low-quality evidence in relation to COVID-19 vaccines in this population. In the instance of future public health emergencies, clinicians and researchers should collaborate closely with patient partners to ensure there is sufficient evidence in the transplant population on patient-important outcomes.