Introduction: Hepatitis B virus can be transmitted through exposure to infected blood or body fluids and can lead to chronic infection and liver failure. In 1991, hepatitis B vaccination was universally recommended for children in the United States. Despite vaccination, Hepatitis B immunity, which can be determined by measuring surface antibody titers, can wane later in life. Previous studies have demonstrated that there is a high prevalence of Hepatitis B non-immunity in pediatric liver transplant recipients after transplantation.
Methods: A retrospective chart review of 344 pediatric patients who have had a liver transplant at Mattel Children’s Hospital at Ronald Reagan Medical Center between the years 2000 and 2018 was conducted using information from both CareConnect and California Immunization Registry (CAIR). From these, 81 patients with post-transplant Hepatitis B titers were included in our study. From these, 38 also had titers checked prior to their transplant. After categorizing the sample into those that had positive and negative titers after transplantation, statistical analyses (Wilcoxon rank sum for continuous variables and chi squared for categorical variables) were conducted to identify risk factors for non-immunity. Descriptive statistics included medians and frequencies. All statistical analyses were done using Stata 15.0.
Results: Of the 81 patients in the study sample, 31 (38.3%) were found to have positive Hepatitis B titers post-transplant (Hepatitis B surface antibody >10U/mL), of which 18 were confirmed to have been vaccinated at some point. Fifty (61.7%) were found to be negative, of which 26 were confirmed to have been vaccinated. The median age of transplantation was found to be 2.23 years, with it as 4.57 years for the positive post-transplant titer group and 1.96 for the negative post-transplant titer group. History of chemotherapy, steroids, and past biopsy proven rejection were not associated with Hepatitis B non-immunity. Longer time since transplant and lower tacrolimus levels were associated with non-immunity (p=0.0075 and 0.035, respectively).
Conclusion: The majority of patients were non-immune to Hepatitis B. A longer time since transplant correlated with a decrease in immunity. In looking at the patients who had both pre and post-transplant testing, it is shown one cannot predict post-transplant Hepatitis B titers based on pre-transplant titers, regardless of vaccination. This underscores the importance of screening for Hepatitis B immunity and treating with booster vaccines when appropriate.