Under-Immunization Still a Major Problem in Pediatric Liver Transplant Patient Population

Media Contact: Caroline Laurin
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San Francisco – Data from a new study presented this week at The Liver Meeting® – held by the American Association for the Study of Liver Diseases – found that more than half of pediatric liver transplant recipients are under-immunized at the time of their transplant and are at increased risk for vaccine-preventable infections.

Vaccine-preventable infections are a serious complication for pediatric patients following a liver transplantation. These infections can lead to significant co-existing diseases and conditions, graft rejection, death and increased medical costs. In a prior study published in The Journal of Pediatrics, researchers at Children’s Hospital Colorado demonstrated that one in six pediatric liver transplant recipients is hospitalized with a vaccine-preventable infection in the first two years following transplantation.

Immunizations are a minimally invasive and cost-effective way to reduce such infections. The research team has continued their work in this project to learn more about the reasons behind the high number of under-immunized pediatric patients.

“Our study, which used the Pediatric Health Information System database, demonstrated that one in six liver transplant recipients was being hospitalized in the first two years post-transplant with an infection that was potentially vaccine preventable,” says Amy Feldman, MD, MSCS, program director, Liver Transplant Fellowship at Children’s Hospital Colorado, and the study’s co-author. “Therefore, we became interested in investigating whether immunizations were an actionable gap in practice that could lead to significantly improved transplant outcomes.”

The researchers collected immunization records at the time of liver transplantation for patients undergoing transplant at one of 39 North American centers in the Studies of Pediatric Liver Transplantation Consortium, or SPLIT, from August 2017 through May 2018. Immunization records were available for 106 of 119 potential subjects (89 percent) from 27 centers.

Using the CDC’s Immunization Schedule, 51 percent of the patients who received their transplant before the age of two, and 40 percent of patients who received their transplant at age two or older, were completely up to date for their age on immunizations. Using an accelerated schedule of immunizations allowed for children awaiting transplantation (published by the American Society of Transplantation and the Infectious Diseases Society of America) only four percent of patients were fully up to date on age-appropriate immunizations at the time of transplant. Out of all 106 patients in the study, five percent had delayed transplant listing to allow time for them to become up to date on their immunizations.

The immunizations most frequently missed were DTaP (diphtheria, tetanus, pertussis) and PCV13 (the pneumococcal conjugate vaccine). The study found that out of 23 children who were six to 11 months old at transplant, who would have been eligible for accelerated live immunizations, only 13 percent had received the MMR (measles, mumps, rubella) vaccine and only nine percent were immunized against varicella prior to surgery. The study also found that out of 79 patients one year or older at transplant, only 80 percent were immunized against hepatitis A despite eligibility. Of 20 children age 11 or older at the time of transplant, only 70 percent had received the DTaP booster and 65 percent had received the HPV (human papilloma virus) vaccine. The researchers found that age, gender, race, ethnicity; and underlying diagnosis were not associated with under-immunization.

The study’s data show that 56 percent of pediatric liver transplant patients are under-immunized at the time of their transplant, leaving a significant portion of transplant recipients at increased risk for vaccine-preventable infections.

“Our study highlights under-immunization as a problem in the transplant population. In future studies, we plan to investigate what are the specific barriers faced by parents, primary care providers and hepatologists that prevent transplant candidates from being fully immunized at the time of transplant,” explains Dr. Feldman. “We then hope to develop tools within the healthcare system that can overcome these barriers and improve immunization delivery to transplant candidates and recipients, ultimately leading to improved post-transplant outcomes.”

Editor’s note: This press release contains updated data that is not reflected in the published abstract, but will be presented at The Liver Meeting®.

Dr. Feldman will present the study entitled “Immunization Rates at the Time of Pediatric Liver Transplant: A Prospective Multicenter Study through the Studies of Pediatric Liver Transplantation (SPLIT)” on Monday, November 12 at 10:30 AM in Room 312/314. The corresponding abstract (number 0240) can be found in the journal, HEPATOLOGY.