Chickenpox is a highly contagious vaccine-preventable disease that can lead to severe complications, especially in immunocompromised patients. Varicella-zoster virus (VZV) vaccine appears to be safe and immunogenic in pediatric solid organ transplant recipients, but there are few data on the long-term vaccine-induced seroprotection.
In this prospective interventional study, we offered 2 doses of VZV vaccine to all eligible and nonseroprotected children seen 1 year after liver transplant. Vaccine responses were measured 1 month later and yearly thereafter. Vaccine safety was closely monitored. A supplementary dose was administered if protective levels were not reached/maintained.
Among 121 enrolled patients, 49 were vaccinated and followed during 5.5 years (interquartile range, 3.7-8.0). Their seroconversion rate reached 100% (97.5% confidence interval [CI], 92.7-100). Low VZV-antibody concentration (≤400 UI/L) after the first 1–2 dose/s was associated with the need for a supplementary dose (odds ratio, 15.0; 95% CI, 3.4-67.0, P = 0.001) and was given to 31% (15/47) of children at 1.1 year (interquartile range, 0.9-3.9). Although antibody concentrations declined during follow-up, 96% (95% CI, 86.0-99.5) of patients maintained protective antibody concentrations at a median of 5.5 years after vaccination. One breakthrough disease was identified.
VZV immunization of pediatric solid organ transplant recipients confers sustained seroprotection.
1 Division of General Pediatrics, Department of Pediatrics, Children’s Hospital, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
2 Department of Pediatrics, University Center of Pediatric Surgery of Western Switzerland.
3 Children’s Hospital, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
4 Division of Pediatric Gastroenterology and Transplantation, Department of Pediatrics, Children’s Hospital, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
5 Departments of Pathology-Immunology and Pediatrics, Centre for Vaccinology, University of Geneva, Geneva, Switzerland.
Received 1 February 2019. Revision received 21 June 2019.
Accepted 27 June 2019.
C.M.V. and L.F.P. participated in the writing of the paper, in conducting the research, and data analysis. V.A.M. and B.E.W. participated in research design, in conducting the research, and contributed new reagents or analytic tools. M.R. participated in conducting the research and data collect. S.G. participated in conducting the research and contributed new reagents or analytic tools. C.-A.S. and K.M.P.B. participated in research design, in the writing of the paper, in conducting the research, and contributed new reagents or analytic tools.
The authors declare no conflicts of interest.
Research grants from Geneva University Hospitals and the Center for Vaccinology and Neonatal Immunology, University of Geneva.
Previous Presentation: This study was presented at the 8th Congress of the International Pediatric Transplant Association; March 28, 2015; San Francisco, CA; and at the 33rd Congress of the European Society for Paediatric Infectious Diseases; May 12, 2015; Leipzig, Germany.
Supplemental digital content (SDC) is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.transplantjournal.com).
Correspondence: Klara M. Posfay-Barbe, MD, MS, Pediatric Infectious Diseases Unit, Children’s Hospital, Geneva University Hospitals, 6 Rue Willy-Donzé, 1211 Geneva 14, Switzerland. (Klara.PosfayBarbe@hcuge.ch).