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Public health challenges in hepatitis C virus infection
J M Kaldor1, G J Dore, P K Correll
1National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales, Sydney, Australia.
Insights
Hepatitis C virus (HCV) diagnosis relies on biased case reports and prevalence surveys. Injecting drug use is the primary transmission route, while sexual transmission is unlikely for public health strategies.
Area of Science:
- Hepatology
- Virology
- Epidemiology
Background:
- Discovery of Hepatitis C virus (HCV) prompted further research into transmission and epidemiology.
- HCV diagnosis is a notifiable condition in some regions, leading to biased case reporting.
- Prevalence surveys are used, but true random sampling is limited.
Purpose of the Study:
- To review the transmission routes and epidemiological distribution of Hepatitis C virus (HCV).
- To evaluate the effectiveness of different methods for tracking HCV prevalence.
- To inform public health strategies regarding HCV transmission.
Main Methods:
- Analysis of HCV case reports and their inherent biases.
- Review of serological prevalence surveys, including those using existing blood samples and specific population recruitment.
- Examination of data on injecting drug use, mother-to-child transmission, and sexual transmission of HCV.
Main Results:
- Injecting drug use is the predominant HCV transmission route in countries with robust blood screening.
- Mother-to-child transmission occurs at approximately 7%, with unknown long-term consequences and no proven prevention.
- HCV is unlikely to be a significant sexually transmitted infection from a population health standpoint.
Conclusions:
- Public health strategies should focus on injecting drug use as the primary HCV transmission route.
- Further research is needed on mother-to-child HCV transmission and long-term outcomes.
- Minimizing blood contact during sexual activity is advised for individuals with HCV infection and their partners.
Abstract:
The discovery a decade ago of the hepatitis C virus (HCV) led to control of post-transfusion hepatitis in many countries, but raised a number of further questions about the transmission and epidemiological distribution of the newly discovered virus. In some countries, the diagnosis of HCV infection has been designated as a notifiable condition, with doctors (or laboratories, or both) required to send case reports to public health authorities. Such case reports of HCV diagnosis are inevitably biased towards people with symptomatic presentations or a known history of exposure, or those who undergo screening for other purposes, such as blood transfusion. Another approach has been the use of serological prevalence surveys either making use of blood that had been taken or tested for other purposes or recruiting specific population groups for the explicit purpose of measuring HCV prevalence. A limited number of surveys have either attempted to obtain true random samples of geographically defined populations, or recruited subjects, such as pregnant women, who may be considered to be broadly representative of the wider population. Injecting drug use is clearly the main mode of HCV transmission in countries that have established comprehensive blood screening, and it remains a major public health challenge. Although mother-to-child transmission is known to occur with a frequency of about 7% there is no proven means of prevention and very little is known about the long-term consequences of maternally transmitted infection. The conclusion from a number of somewhat conflicting studies is probably that HCV infection should not be viewed as a sexually transmissible infection from the perspective of population health strategies. However, people with HCV infection and their sexual partners should minimize the extent of blood contact that may occur through sexual activity.