Measles,mumps, rubella (vaccine) and varicella vaccines in pediatric liver transplant: An initial analysis of post‐transplant immunity

Varicella and measles infection represents a significant source of morbidity and mortality for pediatric LT recipients. We evaluated the prevalence and correlates of post‐transplant immunity in pediatric LT recipients previously immunized against measles (n = 72) and varicella (n = 67). Sixteen of seventy‐two (22%) patients were measles non‐immune, and 42/67 (63%) were varicella non‐immune after LT. Median time from LT to titers for measles and varicella was 4.0 and 3.3 years, respectively. In the measles cohort, non‐immune patients received fewer pretransplant vaccine doses (P = 0.026) and were younger at both time of vaccination (P = 0.006) and LT (P = 0.004) compared with immune patients. Upon multivariable analysis, weight > 10 kg at LT (OR 5.91, 95% CI 1.27‐27.41) and technical variant graft (OR 0.07, 95% CI 0.01‐0.37) were independently, significantly associated with measles immunity. In the varicella cohort, non‐immune patients received fewer pretransplant vaccine doses (P = 0.028), were younger at transplant (P = 0.022), and had less time lapse between their last vaccine and transplant (P = 0.012) compared with immune patients. Upon multivariate analysis, time > 1 year from last vaccine to LT was independently, significantly associated with varicella immunity (OR 3.78, CI 1.30‐11.01). This study demonstrates that non‐immunity to measles and varicella is a prevalent problem after liver transplantation in children and identifies 3 unique risk factors for non‐immunity in this high‐risk population.