Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Jan 27, 2021; 13(1): 120-131
Published online Jan 27, 2021. doi: 10.4254/wjh.v13.i1.120
Immunization status and hospitalization for vaccine-preventable and non-vaccine-preventable infections in liver-transplanted children
Palittiya Sintusek, Yong Poovorawan
Palittiya Sintusek, Thai Pediatric Gastroenterology, Hepatology and Immunology Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Palittiya Sintusek, Department of Pediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok 10330, Thailand
Yong Poovorawan, Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok 10330, Thailand
Author contributions: Sintusek P designed and oversaw the study, drafted the manuscript, collected, interpreted, and analyzed the data, and made critical revisions related to important intellectual content; Poovorawan Y suggested critical intellectual content and approved the final manuscript.
Supported by Thai Pediatric Gastroenterology, Hepatology and Immunology Research Unit, King Chulalongkorn Memorial Hospital, Faculty of Medicine, Chulalongkorn University; The 100th Anniversary Chulalongkorn University Fund for Doctoral Scholarship, Chulalongkorn University; and the Thailand Research Fund Thailand Science Research and Innovation, No. MRG6280190.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board of Chulalongkorn University, Thailand (IRB approval number: 806/62).
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each the patient agreed to treatment by written consent.
Conflict-of-interest statement: The authors have no conflicts of interest to disclose.
Data sharing statement: There are no additional data available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Yong Poovorawan, MD, Professor, Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, 1873 Rama IV Road Patumwan, Bangkok 10330, Thailand.
Received: June 25, 2020
Peer-review started: June 25, 2020
First decision: October 21, 2020
Revised: November 12, 2020
Accepted: November 28, 2020
Article in press: November 28, 2020
Published online: January 27, 2021
Research background

Infection after liver transplantation is a serious concern due to potential morbidity and mortality, thus strategies to reduce overall post-transplant infection are warranted. Immunization is an effective and relatively noninvasive and affordable way to reduce vaccine-preventable infections (VPIs).

Research motivation

There is strong evidence that VPIs and non-VPIs post-transplant cause high fatality and increase graft rejection, but published data on VPIs and their effects in children post-liver transplant in Asia are scarce.

Research objectives

To investigate immunization status in children at the time of liver transplantation and up to 5 years thereafter. The prevalence and impact of VPIs and non-VPIs during hospitalization were also evaluated.

Research methods

The current retrospective study included 77 children who underwent liver transplantation and were followed up for up to 5 years thereafter. Demographic data, patient characteristics, immunization details derived from vaccination records, and hospitalizations for VPIs and non-VPIs were analyzed.

Research results

The mean follow-up duration after liver transplantation was 3.68 ± 1.45 years. Of the 77 children in the study, 48 (62.3%) had vaccination records in their vaccination books. There was a significant difference in the proportion of children with incomplete vaccination according to Thailand’s Expanded Program on Immunization (n = 25, 52%) and accelerated vaccine from Infectious Diseases Society of America recommendations (n = 43, 89.5%) (P < 0.001). Post-liver transplant, almost half of the children in the study did not catch up with appropriate immunizations for age. There were 237 infections requiring hospitalization during up to 5 years of follow-up post-liver transplant at our hospital. The risks of VPIs and non-VPIs were highest during the first year after liver transplantation, and 2 children died. Respiratory and gastrointestinal systems were common sites of infection. The most commonly identified pathogens that caused VPIs were rotavirus, influenza virus, and varicella-zoster virus.

Research conclusions

Incomplete age-appropriate immunization in children pre-liver transplant and post-liver transplant were common. At least 13.1% of the children in the study required hospitalization for a VPI during a follow-up period of up to 5 years post-transplantation. There was high morbidity, especially during the first year after transplantation. Hence, complete immunization and robust infection control should be considered in such children.

Research perspectives

The current study suggests that incomplete age-appropriate immunization is a major concern, because a large number of patients with VPIs requiring hospitalization were recorded. Interestingly, waning immunity post-liver transplant can evidently lead to VPIs, as evidenced by a case in which de novo hepatitis B infection developed 3 years postliver transplantation in a child who had a hepatitis B surface antibody titer of > 1000 mIU/mL pre-liver transplantation. As well as policies to increase pre- and post-transplant immunization rates, studies investigating humoral and cellular immunity induced by vaccination after liver transplantation are needed.