Ochnio J J, Patrick D, Ho M, Talling D N, Dobson S R
Vaccine Evaluation Center, British Columbia's Children's Hospital and University of British Columbia.
CMAJ. 2001 Aug 7;165(3):293-7.
In Canada, inactivated hepatitis A vaccines are targeted selectively at those at increased risk for infection or its complications. In order to evaluate the need for routine hepatitis A vaccination programs in Vancouver for street youth, injection drug users (IDUs) and men who have sex with men (MSM), we determined the prevalence of antibodies against hepatitis A virus (HAV) and risk factors for HAV in these groups.
The frequency of past HAV infection was measured in a sample of Vancouver street youth, IDUs and MSM attending outreach and STD clinics and needle exchange facilities by testing their saliva for anti-HAV immunoglobulin G. A self-administered, structured questionnaire was used to gather sociodemographic data. Stepwise logistic regression was used to evaluate the association between presumed risk factors and groups and past HAV infection.
Of 494 study participants, 235 self-reported injection drug use, 51 were self-identified as MSM and 111 met street youth criteria. Positive test results for anti-HAV were found in 6.3% of street youth (95% confidence interval [CI] 2.6%-12.6%), 42.6% (95% CI 36.2%-48.9%) of IDUs and 14.7% (95% CI 10.4%-19.1%) of individuals who denied injection drug use. Among men who denied injection drug use, the prevalence was 26.3% (10/38) for MSM and 12% (21/175) for heterosexuals. Logistic regression showed that past HAV infection was associated with increased age and birth in a country with high rates of hepatitis infection. Injection drug use among young adults (25-34 years old) was a significant risk factor for a positive anti-HAV test (p = 0.009). MSM were also at higher risk for past HAV infection, although this association was nominally significant (p = 0.07).
Low rates of past HAV infection among Vancouver street youth indicate a low rate of virus circulation in this population, which is vulnerable to hepatitis A outbreaks. An increased risk for HAV infection in IDUs and MSM supports the need to develop routine vaccination programs for these groups also.
在加拿大，甲型肝炎灭活疫苗有选择地面向那些感染风险或其并发症风险增加的人群。为了评估在温哥华针对街头青年、注射吸毒者（IDU）和男男性行为者（MSM）开展甲型肝炎常规疫苗接种项目的必要性，我们测定了这些人群中甲型肝炎病毒（HAV）抗体的流行率以及HAV的危险因素。
通过检测温哥华街头青年、IDU和MSM在 outreach 和性病诊所以及针头交换设施就诊者的唾液中抗-HAV免疫球蛋白G，来测量既往HAV感染的频率。使用一份自行填写的结构化问卷收集社会人口统计学数据。采用逐步逻辑回归来评估假定的危险因素与群体以及既往HAV感染之间的关联。
在494名研究参与者中，235人自述有注射吸毒行为，51人自认为是MSM，111人符合街头青年标准。街头青年中抗-HAV检测呈阳性的比例为6.3%（95%置信区间[CI] 2.6%-12.6%），IDU中为42.6%（95% CI 36.2%-48.9%），否认有注射吸毒行为的个体中为14.7%（95% CI 10.4%-19.1%）。在否认有注射吸毒行为的男性中，MSM的流行率为26.3%（10/38），异性恋者为12%（21/175）。逻辑回归显示，既往HAV感染与年龄增加以及在肝炎感染率高的国家出生有关。年轻成年人（25 - 34岁）中的注射吸毒行为是抗-HAV检测呈阳性的一个显著危险因素（p = 0.009）。MSM既往HAV感染的风险也较高，尽管这种关联在名义上具有显著性（p = 0.07）。
温哥华街头青年中既往HAV感染率较低，表明该人群中病毒传播率较低，但该人群易发生甲型肝炎暴发。IDU和MSM中HAV感染风险增加，这也支持了为这些群体制定常规疫苗接种项目的必要性。
