(5) COVID-19 Vaccination Strategies in Solid Organ Transplant Recipients: A Living Systematic Review and Network Meta-Analysis

PURPOSE: The optimal COVID-19 vaccination strategy in solid organ transplant recipients (SOTRs) remains unclear. We conducted a living systematic review and network meta-analysis (NMA) to explore COVID-19 vaccination strategies in SOTRs. METHODS: We conducted a search of databases from inception to July 2022 for all studies comparing any COVID-19 vaccination strategy in SOTRs. We performed a NMA to evaluate the impact of various vaccination strategies on COVID-19 infection, and COVID-related mortality. We used the GRADE approach for NMA to judge our certainty in the evidence. RESULTS: Of 2,534 publications identified, 27 proved eligible (4 RCTs, 23 observational). Identified RCTs were only subject to narrative summarization due to heterogeneity in their research questions (Figure A). Nine observational studies (76,703 SOTRs, 6.3% heart transplant, 5.2% lung transplant) reported adjusted hazard ratios (HRs) for COVID-19 infection and/or COVID-related mortality. The NMA for the impact of various doses of vaccines on COVID-19 infection suggested a dose-response relationship (Figure B). Compared to no vaccination, three (HR 0.16, 95%CI 0.11-0.22, moderate certainty) or two (HR 0.45, 95%CI 0.35-0.58, moderate certainty) doses of any COVID-19 vaccine showed a strong effect on reducing COVID-19 infection. One dose showed a moderate effect (HR 0.73, 95%CI 0.49-1.07, low certainty) on reducing COVID-19 infection. Two doses of any vaccine showed a moderate effect on lowering risk of mortality in COVID-19 infected SOTRs (HR 0.74, 95%CI 0.63-0.89, low certainty). We did not identify sufficient data to explore effect modification by organ group or immunosuppressant use. CONCLUSION: Current evidence suggests that increasing the number of COVID-19 vaccination doses may provide increasing protection against COVID-19 infection in SOTRs (moderate to low certainty). Further studies are needed to better understand the impact of COVID-19 vaccination on all patient-important outcomes.