急性病毒性肝炎未定型(Acute Hepatitis of Unknown Etiology in Children)目前在英國、美國及歐洲、中東地區與亞洲等部分國家有報告相關病例，截至4月21日，累計169例確定病例，其中英國114例、西班牙13例、以色列12例及美國9例，我國尚無出現任何病例。

根據世界衛生組織(WHO)的資料，患病孩童年齡最小1歲10個月、最大到13歲左右，其症狀包括黃疸、腸胃道症狀、腹痛、嘔吐、黑尿、蒼白灰色的糞便、皮膚癢、肌肉及關節痛、高燒、疲倦無力、食欲降低和腹痛等，嚴重者需要進行肝臟移植。

經實驗室檢測已排除A、B、C、D、E型肝炎病毒，部分病例有感染新型冠狀病毒(SARS-CoV-2)或腺病毒(Adenovirus)的狀況，致病機制調查中、尚無發現明顯流行病學關聯性。

WHO針對此疾病的現行定義如下：
確診病例(Confirmed)：目前尚無明確標準(N/A at present)
可能病例(Probable)：病人有急性肝炎並排除A-E肝炎病毒感染，且AST或ALT>500 IU/L，年齡是16歲(含)以下且是2021年10月1日後發病。A person presenting with an acute hepatitis (non hepA-E*) with serum transaminase >500 IU/L (AST or ALT), who is 16 years and younger, since 1 October 2021.
流病相關病例(Epi-linked)：病人有急性肝炎並排除A-E肝炎病毒感染，不限年齡且與可能病例有密切接觸，2021年10月1日後發病。A person presenting with an acute hepatitis (non hepA-E*) of any age who is a close contact of a probable case, since 1 October 2021.

目前尚無針對此病原體的偵測方法， NHS與UKHSA共同訂定針對此疾病現行的實驗室診斷：

Sample type	Test	Pathogen
Blood	PCR*	Adenovirus, Enterovirus, CMV, EBV, HSV, Hepatitis A, Hepatitis C, Hepatitis E, HHV6 and 7
	Serology*	Hepatitis A, B, C, E, CMV, EBV, SARS-CoV-2 anti-S, SARS-CoV-2 anti-N (only if locally available)
	Culture	Standard culture for bacteria/fungi (only if clinically indicated i.e. fever)
Throat swab*	PCR	Respiratory virus panel (including adenovirus/enterovirus/influenza, SARS-CoV-2)
Stool*	PCR	Adenovirus, sapovirus, norovirus, enterovirus Standard bacterial stool pathogen panel to include Salmonella spp (or stol culture depending on local test availability)
Blood* (whole blood in EDTA and plasma separated specimens)	Toxicology	Local investigations according to history Store samples locally – UKHSA will contact laboratories to request samples
Urine*	Toxicology	Local investigations according to history Store samples locally – UKHSA will contact laboratories to request samples

我國針對此狀況因應如下：若急性肝炎之症狀及ALT上升2.5倍以上，排除藥物、中毒性肝炎、自體免疫性肝炎、酒精性肝炎、膽道疾病、心血管疾病，且血清學檢驗標記(IgM anti-HAV、IgM anti-HBc、HBsAg、anti–HCV、IgM anti–HEV)結果均為陰性時，須立即至傳染病通報系統選擇「急性病毒性肝炎未定型」疾病項目進行通報。

另目前將「急性病毒性肝炎未定型」分類至第三類法定傳染病。

資料來源

1. WHO -Acute hepatitis of unknown aetiology – the United Kingdom of Great Britain and Northern Ireland https://reurl.cc/q5m9En
2. WHO -Multi-Country – Acute, severe hepatitis of unknown origin in children https://reurl.cc/n1nQKd
3. GOV.UK -Guidance: Increase in acute hepatitis cases of unknown aetiology in children https://reurl.cc/2Zbx1r
4. GOV.UK -News story: Increase in hepatitis (liver inflammation) cases in children under investigation https://reurl.cc/3oN8gM
5. US CDC – CDC Alerts Providers to Hepatitis Cases of Unknown Origin https://reurl.cc/Gxdz9G
6. US CDC -Recommendations for Adenovirus Testing and Reporting of Children with Acute Hepatitis of Unknown Etiology https://reurl.cc/Gxdz9y
7. 衛生福利部疾病管制署-傳染病專題：急性病毒性肝炎未定型　https://reurl.cc/55o76q
8. 衛生福利部疾病管制署-致醫界通函：近期歐美等地區發現兒童嚴重不明原因肝炎個案異常增加，籲請醫師對兒童不明原因肝炎個案提高警覺，加強診斷通報(疾病管制署致醫界通函第476號)　 https://reurl.cc/Ernj0R