Prepared or at-risk? Evaluating live viral vaccine coverage and vaccine immunogenicity before pediatric solid organ...

Area of Science:

• Immunology
• Pediatric Medicine
• Transplantation

Background:

• Pediatric solid organ transplant recipients face significant risks from vaccine-preventable diseases.
• Pre-transplant vaccination coverage in this vulnerable population is frequently inconsistent.
• Maintaining adequate immunity is critical for post-transplant outcomes.

Purpose of the Study:

• To evaluate vaccination status and serologic immunity for varicella and measles in pediatric transplant candidates.
• To identify trends in vaccination coverage from initial evaluation through transplantation.
• To assess factors associated with incomplete vaccination and seronegativity.

Main Methods:

• Retrospective cohort study of 421 pediatric transplant recipients (2018-2024).
• Analysis of vaccination status and serologic immunity for varicella and measles at key pre-transplant points.
• Comparison of vaccination rates across different transplant types and age groups.

Main Results:

• At transplant, 19.2% were under-vaccinated for varicella and 21.6% for measles, with infants most affected.
• A notable percentage (7.1% varicella, 8.6% measles) lost vaccination status pre-transplant.
• Kidney recipients had high vaccination rates (>94%), while liver and heart recipients had lower rates (58%-72%).
• Seronegativity was observed in 23.6% for varicella and 13.0% for measles among fully vaccinated patients.

Conclusions:

• Many pediatric transplant candidates, especially infants and those awaiting liver/heart transplants, are incompletely vaccinated.
• Dynamic changes in vaccination status pre-transplant necessitate continuous monitoring.
• Improved vaccination strategies are urgently needed to protect this high-risk population.