Safety and immunogenicity of the live-attenuated varicella vaccine in pediatric solid organ transplant recipients: A systematic review and meta-analysis

Live Vaccine and Varicella Postexposure Prophylaxis in Pediatric Liver Transplant Recipients: A Survey of Practice in Australia and New Zealand

BACKGROUND

Administration of live vaccines following liver transplant (LT) has historically not been recommended due to concerns regarding risk of vaccine-attenuated disease. However, there is evidence suggesting that in select transplant recipients live vaccinations can be administered safely. Studies in other regions have indicated that despite this evidence many clinicians remain hesitant to administer live vaccinations.

METHOD

A REDCap survey was distributed to gastroenterologists, pediatricians, and infectious diseases physicians at pediatric centers across Australia and New Zealand via email between September and November 2023. The survey included a series of questions regarding live vaccine and varicella postexposure prophylaxis (PEP) practices in pediatric LT recipients and barriers to live vaccine administration in this cohort.

RESULTS

There was a total of 16 responses to the survey, from 10 different pediatric centers, including 10/11 pediatric gastroenterology centers and all four pediatric LT centers in the region. Only 31% (5/16) of respondents (from 3/10 different centers) offer live vaccines. The main barrier to live vaccine administration was clinician reluctance and the main reason for not offering live vaccines was insufficient safety data. Sixty-nine percent (11/16) of respondents take vaccination status and/or serology into account when deciding whether to offer varicella PEP to this cohort. Respondents universally offer varicella zoster immunoglobulin as PEP, though 31% (5/16) also offer antiviral medication.

CONCLUSIONS

Many clinicians in our region remain hesitant to provide live vaccines to pediatric LT recipients, with concerns regarding insufficient safety data. Updated local guidelines may help to address this.

Live-attenuated vaccination for measles, mumps, and rubella in pediatric liver transplantation

BACKGROUND

Infections are a serious short- and long-term problem after pediatric organ transplantation. In immunocompromised patients, they can lead to transplant rejection or a severe course with a sometimes fatal outcome. Vaccination is an appropriate means of reducing morbidity and mortality caused by vaccine-preventable diseases. Unfortunately, due to the disease or its course, it is not always possible to establish adequate vaccine protection against live-attenuated viral vaccines (LAVVs) prior to transplantation. LAVVs such as measles, mumps, and rubella (MMR) are still contraindicated in solid organ transplant recipients receiving immunosuppressive therapy (IST), thus creating a dilemma.

AIM

This review discusses whether, when, and how live-attenuated MMR vaccines can be administered effectively and safely to pediatric liver transplant recipients based on the available data.

MATERIAL AND METHODS

We searched PubMed for literature on live-attenuated MMR vaccination in pediatric liver transplantation (LT).

RESULTS

Nine prospective observational studies and three retrospective case series were identified in which at least 833 doses of measles vaccine were administered to 716 liver transplant children receiving IST. In these selected patients, MMR vaccination was well tolerated and no serious adverse reactions to the vaccine were observed. In addition, an immune response to the vaccine was demonstrated in patients receiving IST.

CONCLUSION

Due to inadequate vaccine protection in this high-risk group, maximum efforts must be made to ensure full immunization. MMR vaccination could also be considered for unprotected patients after LT receiving IST following an individual risk assessment, as severe harm from live vaccines after liver transplantation has been reported only very rarely. To this end, it is important to establish standardized and simple criteria for the selection of suitable patients and the administration of the MMR vaccine to ensure safe use.

Parent and healthcare provider views of live varicella vaccination of pediatric solid organ transplant recipients

BACKGROUND

Live attenuated varicella vaccine (LAVV) has historically been contraindicated in children who are immunocompromised due to solid organ transplant (SOT) because of safety concerns. Recently, clinical guidelines were developed that support post-transplant varicella vaccination in selected SOT recipients based on emerging evidence of LAVV safety. This qualitative study sought to explore barriers and facilitators to implementing the new guidelines, as well as acceptability of LAVV among healthcare providers (HCPs) and parents.

METHODS

HCPs and parents of transplant recipients were recruited from four sites using purposive sampling. Data from semi-structured interviews were analyzed using an Interpretive Description approach that incorporated data from the interviews, academic knowledge and clinical experience, and drew from Grounded Theory and Thematic Analysis. The theoretical framework used was Adaptive Leadership.

RESULTS

Thirty-four participants (16 HCPs and 18 parents) were included in the analysis. Parents developed skills in adaptive leadership that included strategies to protect their child against infectious diseases. Foundational information that live vaccines were absolutely contraindicated post-transplant "stuck" with parents and led them to develop strategies other than vaccination to keep their child safe. Some parents struggled to understand that information previously presented as a certainty (contraindication of LAVV) could change. Their approach to adaptive leadership informed their appraisal of the new vaccination guidelines and willingness to accept vaccination.

CONCLUSIONS

HCPs should adopt a family-centered approach to communicating changing guidelines that considers parents' approach to adaptive leadership and discusses the changing nature of medical evidence. Trust between HCPs and parents can facilitate these conversations.