Live vaccines in solid organ transplant recipients

PURPOSE OF REVIEW: Vaccine preventable infections (VPIs) contribute substantially to morbidity and mortality in solid organ transplant (SOT) recipients. Recent outbreaks and declining herd immunity have brought attention to optimizing vaccination pre and posttransplant, as many patients remain incompletely immunized at the time of transplant. This review summarizes modern evidence and evolving recommendations regarding live vaccination in SOT candidates and recipients. RECENT FINDINGS: Vaccination coverage at the time of transplant remains suboptimal, although targeted interventions have shown improvements in uptake. Accumulating data, largely from pediatric liver and kidney SOT cohorts, support the safety and immunogenicity of posttransplant measles, mumps, rubella (MMR) and varicella (VAR) vaccination under defined clinical and immunologic criteria. These findings have informed updated guidance and clinical practice for select pediatric SOT recipients, and multicenter experience with posttransplant live vaccination continues to expand. SUMMARY: Growing evidence suggests that live vaccine administration may be feasible in carefully selected pediatric SOT recipients and may reduce susceptibility to VPIs. Important knowledge gaps remain, particularly for adult SOT recipients, nonliver transplant populations, and other live vaccines. Further research and prospective studies are needed to better define safety, immunogenicity, and optimal vaccination timing in these populations.