Clinical Spectrum of Children with Acute Hepatitis of Unknown Cause.

BACKGROUND: Since January 2022, there has been an increase in reports of cases of acute hepatitis of unknown cause in children. Although cases have been reported across multiple continents, most have been reported in the United Kingdom. Investigations are ongoing to identify the causative agent or agents. METHODS: We conducted a retrospective study involving children referred to a single pediatric liver-transplantation center in the United Kingdom between January 1 and April 11, 2022. These children were 10 years of age or younger and had hepatitis that met the case definition of the U.K. Health Security Agency for confirmed acute hepatitis that was not hepatitis A through E and did not have a metabolic, inherited or genetic, congenital, or mechanical cause, in the context of a serum aminotransferase level greater than 500 IU per liter. We reviewed medical records and documented demographic characteristics, clinical features, and results of liver biochemical, serologic, and molecular tests for hepatotropic and other viruses, as well as radiologic and clinical outcomes. The outcomes were classified as an improving condition, liver transplantation, or death. RESULTS: A total of 44 children had hepatitis that met the confirmed case definition, and most were previously healthy. The median age was 4 years (range, 1 to 7). Common presenting features were jaundice (in 93% of the children), vomiting (in 54%), and diarrhea (in 32%). Among the 30 patients who underwent molecular testing for human adenovirus, 27 (90%) were positive. Fulminant liver failure developed in 6 patients (14%), all of whom received a liver transplant. None of the patients died. All the children, including the 6 who received liver transplants, were discharged home. CONCLUSIONS: In this series involving 44 young children with acute hepatitis of uncertain cause, human adenovirus was isolated in most of the children, but its role in the pathogenesis of this illness has not been established.

Principles of immunisation in children with solid organ transplant.

Vaccine-preventable diseases (VPD) are a significant risk to paediatric solid organ transplant (SOT) recipients on lifelong immunosuppressive therapy. Children progressing to end-stage organ dysfunction are unable to mount a robust immune response. Hence, it is important to plan vaccination early in the course of disease, especially if a child is anticipated to be a SOT candidate. Vaccine recommendations need to be individualised in this population based on vaccine history and serology. Catch-up or accelerated schedules may be used to complete vaccinations before transplant. Post-transplant, immunisation is recommenced in consultation with the transplant team taking into context the time since transplant and the intensity of the immunosuppressive regime. Inactivated vaccines are safe post-transplant but postexposure prophylaxis may still be required in children with inadequate immunity to VPD. Specific vaccines may be advised for SOT recipients travelling abroad (in consultation with a travel clinic) or those entering high-risk professions. Additionally, the vaccination status of all household members and close contacts should be reviewed and optimised, offering additional protection to the transplant recipient.