Spotting a potential threat: Measles among pediatric solid organ transplantation recipients

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.

Immunity Rates of Live Viral Vaccines in Pediatric Renal Transplant Candidates: A Single-Center Experience

OBJECTIVES

Solid-organ transplant recipients are at an increased risk of severe infections due to their immunosuppressed state. Despite the recommendation of routine screening and vaccination before transplant to mitigate this danger, vaccination rates in these patients are still below desirable levels. We aimed to investigate the prevalence of positive antibody rates for measles, mumps, rubella, and varicella among children who are candidates for renal transplant.

MATERIALS AND METHODS

This retrospective study was conducted at a single center and included 144 pediatric kidney transplant patients for the past 7 years. We reviewed the medical records of all participants to evaluate their serologic status for measles, mumps, rubella, and varicella viruses before kidney transplant.

RESULTS

In this study, 144 pediatric kidney transplant candidates (mean age 11.5 years, 56.9% male) were enrolled, and the most frequent causes of the chronic renal disease were congenital anomalies of the kidney and urinary tract and glomerular diseases (32.6%). Seropositivity rates for measles, mumps, rubella, and varicella were 59.0%, 31.9%, 46.5%, and 43.6%, respectively, and all patients who tested negative for antibodies were vaccinated before transplant. Younger age at transplant (OR = 0.909, 95% CI = 0.840-0.923; P = .017) and congenital anomalies of the kidney and urinary tract (OR = 3.46, 95% CI = 1.1548-7.735; P = .002) were significantly associated with increased measles seropositivity, although no significant associations were observed for the other viruses.

CONCLUSIONS

We observed lower seropositivity rates for measles, mumps, rubella, and varicella in pediatric kidney transplant patients versus healthy children and other previous studies. It is essential to address these suboptimal rates to protect the health of these vulnerable patients. Future research should focus on targeted interventions to improve vaccination rates and outcomes in this population.

Implementation of a vaccination clinic for adult solid organ transplant candidates: A single-center experience

Vaccination is an evidence-based strategy to prevent or reduce the severity of infectious diseases (ID). Here, we aimed to describe the experience of implementing a vaccination clinic specifically targeting liver, heart, lung, and combined dual organ transplantation at a single transplantation center in Denmark. In this cohort of 242 solid organ transplant (SOT) candidates, we investigated seroprotection and the proportion of recommended vaccinations documented before transplantation. Furthermore, we registered completed vaccinations after ID consultations. The median age in our cohort was 53 years (IQR, 42-60), 60% were males (n = 135), and liver transplants (n = 138; 57%) were the most frequently planned organ transplants. Before the consultation to the vaccination clinic, influenza and pneumococcal vaccines had the highest proportion of documented vaccination (58% and 37%, respectively). Serological protection was more frequently observed for measles, mumps, or rubella (MMR, approximately 90% for each), while only 30% (n = 72) of SOT candidates showed seroprotection against pneumococcal disease. All SOT candidates required at least one of the recommended vaccines, and over 90% required three or more. At least 10% of patients in our cohort needed a live attenuated vaccine for either MMR or yellow fever. The most frequently administered vaccine was the tetanus-diphtheria-acelullar pertussis (Tdap) booster (n = 217; 90%), influenza vaccination was either administered (n = 16; 7%) or recommended (n = 226; 93%), PCV13 was administered (n = 155; 64%) or recommended (n = 27; 11%), and PPSV23 was either administered (n = 18; 7.4%) or recommended (n = 140; 58%). All SOT candidates adhered completely to their vaccination schedules. Based on our findings, we recommend prioritizing vaccination before transplantation by providing ID consultations for SOT candidates.