Strategy 2: Surveillance
- The purposes of conducting surveillance for viral hepatitis are threefold [39]:
- To detect outbreaks, monitor disease trends and identify risk factors for new incident infections
- To estimate the prevalence of chronic infections and monitor trends in the general population or in highly affected groups
- To estimate the burden of sequelae due to chronic hepatitis, including cirrhosis and HCC
- The ultimate goal of conducting surveillance for viral hepatitis is to direct and evaluate interventions to prevent, control and treat viral hepatitis.
- As described in the local situation in the Introduction, surveillance of viral hepatitis has been conducted through different mechanisms. The notification system is in place for acute viral hepatitis surveillance, while seroprevalence data in different communities are regularly reported to DH for assessing the burden of chronic HBV and HCV infection.
- The present surveillance system carries some limitations. Firstly, substantial under-reporting cannot be ruled out, due to the asymptomatic nature of infection. Secondly, the seroprevalence data collected by DH are limited to specific subgroups, such that generalisation of the results to the entire population should be made with caution. Thirdly, surveillance efforts for viral hepatitis have evolved from relying on clinicians’ report of patients with illnesses compatible with acute hepatitis to increasingly common laboratory-based reporting of serologic markers for viral hepatitis. Besides increasing the completeness and timeliness of case identification, laboratory-based reporting also identifies asymptomatic individuals with newly acquired infections, individuals with chronic infection, and individuals for whom there is insufficient information to verify the diagnosis based on laboratory testing alone. As such, the number of asymptomatic persons identified can be highly variable depending on testing practices, resulting in artificial variation in incidence temporarily [40].
To achieve the WHO 2030 targets, additional information is required to support the evidence-based policy-making for prevention and control of HBV and HCV infection, as well as close monitoring of the progress towards these goals in Hong Kong.
A consistent approach should be adopted for the measurement of the Local Indicators regularly. As such, comparability of the indicators over time can be ensured for monitoring the progress towards the 2030 WHO targets.
| Actions |
| 2.1 |
The current surveillance on viral hepatitis, including the notification system for acute infection, assessment for chronic infection and evaluation of hepatitis B vaccination coverage, will be continued.
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| 2.2 |
To enhance the current surveillance system of viral hepatitis, a set of twelve local indicators, based on the core indicators for assessing the corresponding health sector response suggested by the WHO, are adopted after considering their usefulness, applicability and relevance in the local setting (Table 6).
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| 2.3 |
The next Population Health Survey (PHS), a territory-wide survey with two components, namely household questionnaire survey and health examination, will be conducted by DH in 2020-21. It covers the land-based non-institutional population aged 15 or above for household questionnaire survey and a subsample of respondents aged between 15 and 84 for health examination. It will provide a representative and detailed analysis of the latest prevalence of chronic HBV and HCV infection in the general population (Local Indicators 1, 2), as well as the proportion of patients with chronic HBV and HCV infection who have been diagnosed (Local Indicator 5). For Local Indicators 6 - 9, clinical data from HA will be the main data source as the majority of local population is receiving outpatient and inpatient services for viral hepatitis in HA. The well-established information system in HA also allows continuous and systematic collection of related clinical data.
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| 2.4 |
A consistent and sustainable approach would be adopted for the measurement of the Local Indicators regularly for 2015, 2020, 2025 and 2030.
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Table 6. List of local indicators developed for monitoring and evaluation of viral hepatitis elimination strategies
| Local Indicator |
Description of the Indicator |
| 1 |
Prevalence of chronic HBV infection |
| 2 |
Prevalence of chronic HCV infection |
| 3 |
Coverage of timely hepatitis B vaccine birth dose (within 24 hours) and other interventions to prevent MTCT of HBV |
| 4 |
Coverage of third dose of hepatitis B vaccine among infants |
| 5 |
People living with HCV and/or HBV diagnosed |
| 6 |
Treatment coverage for hepatitis B patients |
| 7 |
Treatment initiation for hepatitis C patients |
| 8 |
Viral suppression for chronic hepatitis B patients treated |
| 9 |
Cure for chronic hepatitis C patients treated |
| 10 |
Cumulated incidence of HBV infection in children 5 years of age |
| 11 |
Incidence of HCV infection |
| 12 |
Deaths attributable to HBV and HCV infection |
* Definition, corresponding WHO targets, data collection methods and provisional figures, where available, are provided in Annex I