Abstract
Measles, mumps, rubella (MMR), and varicella incidence rates have increased due to the delayed vaccination schedules of children secondary to the COVID-19 pandemic. Decreased herd immunity creates a risk for immunocompetent children and immunocompromised individuals in the community. Historically, live-attenuated vaccines (MMR and varicella) were recommended before solid organ transplants. The amount of time before transplant when this is appropriate is often debated, as is the utility of vaccine titers. MMR and varicella vaccines previously were not recommended in immunocompromised patients post-solid organ transplant due to the undue risk of transmission and posed infection risk. The new literature on live-attenuated vaccines in post-transplant pediatric patients provides more insight into the vaccines' safety and efficacy. The present article aims to provide guidance on live-attenuated vaccines (MMR and varicella) in the pre-transplant and post-operative solid organ transplant phases of care in pediatric patients.