Overview of the Global Outbreak of Acute Severe Hepatitis of Unknown Etiology in Children and Enhanced Surveillance Measures, Taiwan, 2022

DOI: 10.6524/EB.202507_41(14).0001

Hsiao-Chi Wang^1*, Wei-Jhe Sun¹, Wei-Lun Huang², Shu-Wan Jian¹, Chien-Bang Hsu¹, Hao-Yuan Cheng¹, Chiu-Mei Chen¹, Chia-Lin Lee¹, Jyh-Yuan Yang², Hung-Wei Kuo¹

2025 Vol.41 NO.14

Correspondence Author： Hsiao-Chi Wang

Abstract：

    In April 2022, the United Kingdom reported multiple cases of acute hepatitis of unknown etiology in children, followed by similar outbreaks in other countries. By July, 1,010 probable cases had been reported across 35 countries, with 46 requiring liver transplants and 22 resulting in death. Given the limited evidence available at the time, the possibility of human-to-human transmission could not be ruled out, and the World Health Organization assessed the risk at the global level as moderate.
    To monitor the situation in Taiwan, enhanced surveillance was conducted from August 4 to December 31, 2022. There were 14 probable cases identified, with over 80% occurring in children aged less than five years, a demographic distribution similar to that observed in European Union countries. Clinical symptoms were predominantly non-specific, such as fever and gastrointestinal symptoms, consistent with findings from Japan and South Korea. The adenovirus positivity rate in Taiwan was 7%, approximately one-tenth of the 67.7% reported by WHO and the UK. No cases in Taiwan required liver transplantation or resulted in death.
    Given the global decline in cases, the lack of identifiable risk factors, and the sporadic nature of cases in Taiwan, with no major pathogens detected, enhanced surveillance was ended in early January 2023. Routine surveillance resumed under category III of notifiable diseases, "Acute Viral Hepatitis, Unspecified," with continued specimen testing. Taiwan will also continue to monitor international developments to ensure early detection and response.