丙型肝炎 (簡稱丙肝) 由丙型肝炎病毒經血液或體液傳染，是形成肝硬化和肝癌的主因。
 
 
全球超過 150萬人感染了慢性丙肝病毒，本港慢性丙肝患者只佔人口的 0.1% 至 0.3% 。但在某些人士當中，丙肝的流行率郤特別高，例如約有半數曾共用針筒人士均受到丙肝病毒感染。
 
圖表 1 丙肝在香港不同人口類別的流行程度
類別
測試 人數
 丙型肝炎帶病毒者
人數 比例 (%)
捐血者 1,187,587 249 <0.1
曾輸血者 630 64 9.8
濫藥者 1096 485 44.3
Source: Centre for Health Protection. Surveillance of Viral Hepatitis in Hong Kong – 2007 Update Report
 
 
丙肝病毒是經血液或體液傳播，一般接觸如與患者用膳，是不會被傳染。 1987年前，輸血和血液製品都是丙肝主要傳播的途徑。因此，紅十字會對所有收集回來的血液樣本，均進行丙肝抗體測試。目前，共用針頭仍是最常見的丙肝傳播途徑；其次便是針筒再用、紋身、剃鬍子、針灸和穿耳等；另一方面，若患者只有一位性伴侶，亦會減少傳播的風險。
 
 
現今對治療急性或慢性丙肝已有相當成效，超過九成急性丙肝患者服用干擾素療程後，都能消除體內病毒；至於慢性丙肝患者的基礎療程是聚乙二醇干擾素加利巴韋林，有五至六成患者可以消除體內病毒。

病毒基因型影響了治療的成效，而丙肝病毒共分為六個基因型；有八至九成基因2或3型患者在療程後都能消除體內病毒。相比之下，只有四至五成1型患者會對治療產生反應。因此，除非基因2或3型患者對療程有排斥反應，否則目前指引都建議為他們進行治療。至於其他基因型的患者，治療與否將取決於其肝臟是否已受嚴重損害。

由於標準治療對部分患者無效，多款新的抗病毒藥物正在研發當中，並有望於數年間面世。這些藥物都有助治療較難及對治療曾經無效的患者。
 
 
Hepatitis C is caused by an infectious agent called the hepatitis C virus. It is one of the leading causes of cirrhosis and liver cancer worldwide.
 
 
How common is it?More than 150 million people are chronically infected with the hepatitis C virus worldwide. In Hong Kong, 0.1% to 0.3% of the general population suffers from chronic hepatitis C. However, the prevalence is much higher in certain high risk groups. Approximately 50% of current or ex-injecting drug users are infected by the virus.
 
Table 1. Prevalence of hepatitis C in different population in Hong Kong
Category
Tested persons
 Hepatitis C patients
Persons (%)
Blood donors 1,187,587 249 <0.1
Previous transfusion 630 64 9.8
Drug abusers 1096 485 44.3
Source: Centre for Health Protection. Surveillance of Viral Hepatitis in Hong Kong – 2007 Update Report
 
 
Hepatitis C virus is transmitted through contact with blood or body fluid. Casual contact, including eating with infected persons, is safe. Before 1987, transfusion with blood or blood products is a major sousrce of transmission. However, the risk of acquiring the virus through transfusion is very low nowadays because all blood donors have been screened for the infection. Currently, sharing needles is the most common route of transmission. If the instruments are reused, tattooing, shaving, acupuncture and ear-piercing also risk transmission. On the other hand, the risk of sexual transmission is low in patients with a single sexual partner.
 
 
Most patients with chronic hepatitis C are asymptomatic. Occasionally, they may have non-specific symptoms like malaise and reduced appetite.

Patients who acquire the infection recently have acute hepatitis C. Again, the majority remains asymptomatic. Some patients may develop jaundice and tea-colored urine.

More prominent symptoms may occur when cirrhotic complications and liver cancer develop. At this stage, a patient may present with jaundice, tea-colored urine, abdominal pain, abdominal distension, confusion or gastrointestinal bleeding.

Overall, 20% of infected patients develop cirrhosis in 20 to 30 years. Once cirrhosis develops, liver cancer occurs at 1% to 4% per year.
 
 
Nowadays, there are effective treatment for both acute and chronic hepatitis C. In patients with acute hepatitis C, a course of interferon treatment can eradicate the virus in more than 90% of cases. For chronic hepatitis C, the standard treatment is peginterferon plus ribavirin. After a course of treatment, eradication of the virus can be achieved in 50% to 60%.

Viral genotype is the most important factor determining the success of treatment. Hepatitis C virus is divided into 6 genotypes. In patients chronically infected with genotypes 2 or 3 hepatitis C virus, 80% to 90% achieve complete viral eradication after a course of antiviral treatment. In contrast, only 40% to 50% of patients infected with genotype 1 hepatitis C virus respond to treatment. Therefore, current guidelines recommend treatment in all patients with genotypes 2 or 3 virus unless there are contraindications to treatment. For patients with other genotypes, treatment would be considered if there is evidence of significant liver injury.

Since some patients would not respond to the standard treatment, new antiviral drugs are being developed and will be available in the next few years. These drugs will be beneficial for difficult-to-treat patients and patients who have failed treatment previously.