Data to Monitor Viral Hepatitis Elimination in the United States

For decades, viral hepatitis has contributed to substantial morbidity and mortality in the United States. Although there have been considerable public health successes—including a vaccine for hepatitis A, a vaccine for hepatitis B, and a cure for hepatitis C—far too many people experience the consequences of these preventable infections, including liver cirrhosis, cancer, and death. During 2023, more than 86 000 acute cases of viral hepatitis were estimated to have occurred, and more than 13 000 viral hepatitis–related deaths were reported in the United States. ¹ Substantial disparities have been noted for viral hepatitis, including by socioeconomic status, health insurance access, and race and ethnicity, yet data are insufficient to understand the drivers of these disparities. The US Department of Health and Human Services ² and the Centers for Disease Control and Prevention (CDC) ³ aim to eliminate viral hepatitis as a public health threat by 2030. However, improved capacity to collect, analyze, and disseminate robust data for public health action at national, state, and local levels will be crucial to achieve these goals.

Currently, surveillance for viral hepatitis in the United States is based on 3 core CDC data systems: the National Notifiable Diseases Surveillance System (NNDSS), ⁴ the National Health and Nutrition Examination Survey (NHANES), ⁵ and the National Vital Statistics System. ⁶ The history of viral hepatitis surveillance in the United States and the strengths and limitations of these systems, as well as how each data system can be used to characterize viral hepatitis–related morbidity and mortality, are described by Jiles et al in this supplemental issue. The authors state that disease surveillance is an essential component of public health, and despite substantial improvements to viral hepatitis surveillance efforts in recent decades, further advancements are necessary to provide a comprehensive understanding of disease incidence and prevalence in the United States. ⁷ The other 8 articles in this supplemental issue provide an additional overview of the history of viral hepatitis surveillance in the United States, the progress made thus far, and advances in data modernization and other tools that are still needed to support and measure progress toward elimination.^8-15

Hepatitis A

Hepatitis A is a vaccine-preventable liver disease caused by the hepatitis A virus (HAV) and is typically acquired through fecal–oral transmission, primarily through person-to-person contact or consumption of contaminated food or water. Hepatitis A typically results in a mild, short-term illness, and adults are more likely than children to have symptomatic infection. Hofmeister et al ⁹ used NNDSS and NHANES data to describe the epidemiology of HAV in the United States. The authors used NNDSS data to assess trends in new infections from 1966 through 2020. Despite a substantial reduction in HAV infection in the United States after the introduction of a vaccine in the late 1990s, beginning in 2016, widespread outbreaks resulting from person-to-person transmission, primarily among people who use drugs and people experiencing homelessness, spread across 37 states.^16,17 The authors describe the unprecedented 850% increase in hepatitis A incidence from the beginning of the outbreaks in 2016 to the peak in 2019. These outbreaks occurred primarily among people who use drugs and people experiencing homelessness. The authors also used NHANES data to highlight gaps in hepatitis A vaccine coverage among groups at high risk for infection (eg, people who use drugs), despite recommendations for vaccination by the Advisory Committee on Immunization Practices. ¹⁸ The authors concluded that enhancements to case surveillance, including improved characterization of risk behaviors and exposures, are needed to implement prevention measures, and linkage with immunization information systems is needed to monitor progress toward hepatitis A elimination goals.

Hepatitis B

Hepatitis B is a vaccine-preventable liver disease caused by the hepatitis B virus (HBV). The virus is transmitted through exposure to infected blood and body fluids and can lead to both short-term (acute) and long-term (chronic) infection. Although the number of new HBV infections decreased substantially after the introduction of a hepatitis B vaccine in the 1980s, decreases have largely stalled in the past decade.^19,20 Approximately 660 000 people are estimated to have chronic hepatitis B in the United States, and an estimated 1 in 2 people with chronic hepatitis B are unaware of their infection. ²¹ Although no cure for hepatitis B exists, antiviral treatment can prevent progression to liver cirrhosis, cancer, and death. Despite the availability of treatment, approximately 1700 hepatitis B–related deaths occur each year. In addition, mortality rates are substantially higher among non-Hispanic Asian/Pacific Islander people and non-Hispanic Black people than among people in other racial and ethnic groups. ¹ Two articles in this supplemental issue provide an overview of hepatitis B and describe opportunities for monitoring the continuum of care.^10,11

Bixler et al ¹⁰ reviewed surveillance strategies that are critical for monitoring progress toward elimination of hepatitis B as a public health threat in the United States, including using NNDSS to monitor case surveillance, NHANES to monitor chronic hepatitis B prevalence, the National Immunization Survey to monitor vaccine coverage, and other data sources such as Surveillance Epidemiology and End Results–Medicare data to monitor morbidity and mortality outcomes associated with hepatitis B. ¹⁰ The authors summarize available data and limitations with each surveillance strategy, highlighting the need for better data to support programmatic strategies. These strategies include improving vaccination rates among US-born adults with risk behaviors who did not receive routine vaccination as infants and screening and linkage to care for non–US-born people, who have a higher prevalence of chronic hepatitis B than US-born people because of the acquisition of infection perinatally in countries with high endemicity.

Care cascades, or care continuum models, are critical tools to identify and address gaps in care. Originally introduced for HIV, care cascades follow the proportion of people who achieve successive steps in the continuum of diagnosis, linkage to care, retention in care, treatment initiation, and viral suppression. Spradling et al ¹¹ explored hepatitis B care continuum models, recognizing the additional complexity when developing a continuum of care for hepatitis B compared with hepatitis C or HIV, because treatment is not indicated for all people with chronic hepatitis B. Because treatment is not indicated for all people with chronic hepatitis B, it is difficult for public health systems to monitor hepatitis B treatment systematically. The authors describe how investments in public health surveillance infrastructure, including electronic laboratory reporting and interoperability with supplementary data sources such as private health care networks, could enable jurisdictional health departments to develop continuum models. These continuum models can focus, at least initially, on early steps (eg, timely diagnosis, linkage to care, retention in care), all of which can improve outcomes.

Hepatitis C

Hepatitis C is a liver disease caused by the hepatitis C virus (HCV) and is the most common bloodborne infection in the United States. Like hepatitis B, hepatitis C can lead to both acute and chronic infection. Rates of acute hepatitis C have soared during the past decade, most notably because of increases in injection drug use. ²² More than 2.4 million people are estimated to have hepatitis C in the United States, and approximately 1 in 3 people are unaware of their infection; higher prevalence rates are associated with lack of health insurance and poverty.^16,23 Although a safe and effective cure became available in 2013, hepatitis C remains a leading cause of chronic liver disease, liver cancer, and death in the United States, and more than 11 000 people died from hepatitis C–related causes in 2023. ¹ In addition, substantial disparities exist by race and ethnicity—rates of both acute hepatitis C and hepatitis C–related mortality are highest among non-Hispanic American Indian/Alaska Native people and non-Hispanic Black people. ¹ Four articles in this supplemental issue summarize hepatitis C surveillance trends, testing trends, opportunities for monitoring the hepatitis C care cascade, and co-infection with HIV.^12-15

Barker et al ¹² provide a topical review of hepatitis C surveillance in the United States, including the history, long-term trends, and public health investments to strengthen and modernize the surveillance workforce and systems. The authors use NNDSS surveillance data to summarize trends from 1974 (before discovery of HCV in 1989, when it was reported as unspecified hepatitis and later non-A/non-B hepatitis) through 2022 and provide a summary of hepatitis C prevalence estimates generated from NHANES data from 1988 through 2023. The authors also describe trends in hepatitis-related deaths during 1979-2022. Barker et al highlight several challenges in using these data to assess epidemiologic trends, including changes in data collection and reporting over time (eg, because of changes in case definitions and their implementation by health departments), lags in data availability, and incomplete information. The authors emphasize the need to strengthen and modernize systems (eg, implementing electronic laboratory reporting, electronic case reporting), improve system interoperability (eg, health care and public health information systems), and use data linkage to ensure robust data for measuring progress toward hepatitis C elimination goals.

In addition to the core surveillance data systems described previously, Ly et al ¹⁴ demonstrate the utility of accessing additional data sources to monitor progress toward hepatitis C elimination goals. They provide parallel views of commercial laboratory data and NNDSS case surveillance data to assess trends in HCV testing, infection, and hepatitis C cases among US adults. HCV testing increased from 2013 to 2021, suggesting uptake of HCV screening and testing recommendations, which have expanded during the past 25 years. The greatest percentage-point increase in HCV antibody testing occurred in hospitals and substance use disorder treatment facilities and among addiction medicine providers. The authors highlight the need to use supplementary data to inform public health strategies, such as HCV RNA reflex testing and outreach to populations most at risk for hepatitis C.

Montgomery et al ¹³ describe how hepatitis C care cascades can be used to monitor progress toward hepatitis C elimination goals from the health system, public health jurisdiction, and national perspective. They describe potential data sources to develop cascades and highlight the strengths and limitations of each perspective. Cascades in health care settings provide actionable data to improve health care quality and delivery of services in a single health system. In public health settings at jurisdictional and national levels, hepatitis C care cascades describe diagnosis and treatment for populations, which can be challenging to develop in the absence of a single data source containing complete, comprehensive, and timely data representing all steps of a cascade. The authors emphasize the need to strengthen collaborations between health systems and public health and use examples from the Massachusetts Department of Public Health as a case study to illustrate how multiple data sources can be leveraged to produce HCV care cascades to inform public health action.

The hepatitis C epidemic in the United States intersects with the HIV epidemic via shared risk behaviors and long-standing disparities in disproportionately affected populations, including people who inject drugs (PWID). ¹⁵ National plans to end the hepatitis C and HIV epidemics among PWID share important prevention strategies.^2,24 Moorman et al ¹⁵ summarize evidence of the prevalence of HCV infection in recent US HIV clusters and outbreaks among PWID during 2005-2021. Characterizing the prevalence of HCV–HIV co-infection offers improved data to address the health disparities and social drivers associated with coinfection. The authors call for integration of HIV and HCV surveillance systems, improved data on injection drug use, and incorporation of social determinants of health (SDOH) data to overcome disease-specific silos and provide holistic services to people with HCV–HIV co-infection. ¹⁵

Social Determinants of Health

Long-standing and emerging public health challenges, including demographic disparities, put 2030 viral hepatitis elimination goals at risk. Without promoting health equity, these elimination goals will not be met. Data on health equity, including on SDOH, are crucial for informing planning for public health interventions and monitoring their impact. This supplemental issue includes a commentary by Lewis et al ⁸ that details demographic disparities in viral hepatitis and describes differences in acute infections, chronic infections, and mortality by age, sex, and race and ethnicity. The authors describe the importance of understanding how SDOH, such as economic stability, health care access, health insurance, incarceration, and drug use, perpetuate disparities in viral hepatitis. However, SDOH data collected through NNDSS are limited, making it challenging to conduct individual-level analyses to understand the role of SDOH on viral hepatitis outcomes. The authors describe a single approach to overcome this challenge: aggregating person-level data from NNDSS to the geographic level (eg, census tracts, counties) and merging these data with other data sources that provide more in-depth contextual information. These methods can provide insight into communities with high infection rates to inform targeted public health interventions to reduce morbidity and mortality.

Discussion

This supplemental issue was motivated by several key developments that have occurred since the publication of 2 previous Public Health Reports supplements on viral hepatitis in 2007 ²⁵ and 2016. ²⁶ The Viral Hepatitis National Strategic Plan was released in 2020, ² which provides a framework to eliminate viral hepatitis by 2030, and the World Health Organization developed interim guidance on the processes and standards for validation of elimination in 2021. ²⁷ The launch of Healthy People 2030 in 2020 ²⁸ also called attention to viral hepatitis elimination objectives and provided strategies and data practices to support advancement of health equity. During this same period, a resurgence of hepatitis A occurred in ongoing multistate outbreaks in the United States that were associated with homelessness and drug use, ²⁹ emphasizing the need for improved surveillance and prevention.

Several key themes emerge from this supplemental issue. First, improvements in core surveillance are needed to support viral hepatitis elimination efforts. Prior to 2021, only 14 states were receiving federal funds for viral hepatitis surveillance. This underinvestment has led to an inadequate infrastructure, data systems, and workforce. A recent survey of health departments found that 20% of viral hepatitis programs lacked even 1 full-time staff member, 35% were not able to produce surveillance summaries, and only 3% were able to make progress toward elimination goals with existing levels of CDC funding. ³⁰ In 2021, CDC began funding 59 jurisdictions to build viral hepatitis surveillance capacity and implement prevention activities through the cooperative agreement Integrated Viral Hepatitis Surveillance and Prevention Funding for Health Departments (CDC-RFA-PS21-2103). ³¹ Although funding is modest, many recipients showed improvements in the first 2 years, including improved surveillance data quality and completeness. ³²

Building the basic surveillance infrastructure necessary to conduct comprehensive surveillance requires strengthening and modernizing the viral hepatitis workforce and systems. Upskilling the workforce and providing data science tools to improve situational awareness of viral hepatitis can inform the implementation of prevention efforts. In addition, longitudinal patient-level surveillance registries are needed for comprehensive monitoring of hepatitis B and hepatitis C across the continuum of care. Improving data system interoperability, including integration of electronic laboratory reporting and electronic health information directly into surveillance systems, can reduce workload and improve data completeness and timeliness. Linkage of surveillance systems with additional data sources, such as vital statistics data to describe perinatal exposures and viral hepatitis–related deaths, prescription data to monitor treatment, and immunization data to understand hepatitis A and hepatitis B vaccination coverage, can inform the provision of care, treatment, and prevention resources. Testing and treatment data from settings that serve populations at high risk for hepatitis C (eg, syringe service programs, drug treatment programs, carceral facilities) are also needed to inform targeted allocation of resources to cure hepatitis C and prevent new infections. Strategies for improving viral hepatitis surveillance described in this supplemental issue closely align with CDC’s overarching Public Health Data Strategy. ³³

Conclusion

For too many years, viral hepatitis has caused needless morbidity and mortality for thousands of people, which has resulted in worsened disparities among people who have historically been economically and socially marginalized, including people experiencing poverty, homelessness, substance use disorder, and incarceration. Although the vaccines, treatments, and other tools necessary to eliminate viral hepatitis as a public health threat are available, achieving national elimination goals will require concerted efforts to build the robust evidence base needed to implement interventions where they matter the most. This supplemental issue highlights strategies and opportunities to strengthen long-standing surveillance approaches by investing in workforce training and modernization of data systems and processes. We hope this supplemental issue serves as a roadmap on how data can be leveraged to accelerate the delivery of clinical and preventive services where they can have the greatest effect on reducing viral hepatitis–related morbidity and mortality.