Seroepidemiology of hepatitis C

Screening at HKRCBTS indicates that some 0.2-0.3% of the new blood donors have been infected with hepatitis C.
In a study by Chan et al¹³ in 1988, 382 individuals who attended a health exhibition were tested for anti-HCV antibody. Clinical subjects were also recruited from an outpatient liver disease clinic, STD clinics, dialysis centers and drug rehabilitation centers. The prevalence rates of HCV are shown in table 23. It was highest at 66.8% in intravenous drug users.

	anti-HCV
risk groups	no. tested	no. positive	%
general population	382	2	0.5
IV drug users	175	117	66.8
Haemophiliacs	25	14	56.0
haemodialysis	65	3	4.6
sexually active groups/partners of HCV patients	82	0	0

table 23 - prevalence of anti-HCV antibody among different groups

Among 212 blood donors who tested positive for hepatitis C in the period 1991-94, serotyping assay was performed¹⁴. It was found that the most common genotype was 1b (58.8%), followed by type 6a (27.0%). A significantly greater number of donors infected with HCV-6a reported a history of drug abuse (66%) than donors infected with HCV-1b (7%).

Seroepidemiology of hepatitis E

In a retrospective study by Lok et al¹⁵, sera from 394 patients with acute viral hepatitis and 355 healthy subjects were tested fir antibodies to HEV. 65 (16.5%) patients with hepatitis were positive for IgG anti-HEV and 23 (5.8%) were also positive for IgM anti-HEV (Table 24).

		no(%) of patients positive for:
age	n	Ig G anti-HEV	IgM anti-HEV
11-20	81	4(5)	1(1)
21-30	175	35(15)	66.8
31-40	25	17(28)	56.0
>40	65	9(45)	2(10)
total	82	65(16.5)	23(5.8)

table 24- prevalence of IgM and IgG anti-HEV among patients with acute viral hepatitis

Of the healthy subjects, 57 (16.1%) were anti-HEV positive, 14 (3.9%) were also positive for IgM anti-HEV (table 25).

		no(%) of patients positive for:
age	n	Ig G anti-HEV	IgM anti-HEV
1-10	73	2(3)	2(3)
11-20	73	4(6)	0
21-30	82	17(21)	6(7)
31-40	58	14(24)	4(7)
41-50	34	10(30)	1(3)
>50	35	10(29)	1(3)
total	355	57(16.1)	14(3.9)

table 25 - prevalence of IgM and IgG anti-HEV in healthy subjects

IgG anti-HEV was found in a significantly lower proportion of subjects aged under 20 than in older subjects 6 (4%) vs 51(24%), (p<0.0001).