National Progress Report 2025 Goal: Reduce estimated* new hepatitis A virus infections by ≥40%

Estimated* new hepatitis A virus infections

Source: CDC, National Notifiable Diseases Surveillance System
*The number of estimated viral hepatitis infections was determined by multiplying the number of reported cases by a factor that adjusted for under-ascertainment and under-reporting (1–2).

Summary of Findings

The number of estimated new hepatitis A virus (HAV) infections has increased since 2014 with a near 3-fold increase from 2017 to 2018 alone. As the number of infections in 2018 was estimated to be 24,900, the 2018 target of 6,250 was not met. The incidence of hepatitis A is subject to variation from year to year, in large part due to hepatitis A outbreaks. Since late 2016, there have been widespread outbreaks of hepatitis A across the United States, spread through person-to-person contact primarily among persons reporting drug use or homelessness.  Prior to that, in 2013, outbreaks occurred in several southwestern states and Hawaii among persons who consumed imported pomegranate seeds. In early 2016, two hepatitis A outbreaks occurred, both attributed to imported foods: one to frozen strawberries and one to raw scallops.

Reduction needed to meet 2025 goal: An 83.9% reduction from the estimated number of HAV infections in 2018 is needed to meet the 2025 goal of 4,000 estimated infections.

This reduction can best be achieved by

• Disseminating and implementing recently updated CDC recommendations for hepatitis A vaccination (including post‑exposure prophylaxis) to target emerging at-risk populations.
• Strengthening state and local health departments’ outbreak detection and response.
• Promoting evidence-based strategies to increase vaccination as recommended by the Community Preventive Services Task Forceexternal icon.
• Analyzing available data and other strategic information to detect at-risk populations and gaps in vaccination coverage.
• Continuing to promote routine childhood vaccination schedules and vaccination of adults at increased risk for hepatitis A according to Advisory Committee on Immunization Practices (ACIP) Vaccine Recommendations and Guidelines.

Technical Notes

Data Sources: CDC, National Notifiable Diseases Surveillance System (NNDSS)

Numerator: Number of estimated HAV infections

Denominator: Not applicable

Indicator Notes: (1) The NNDSS is a nationwide collaboration that enables all levels of public health to share notifiable-disease-related health information. Surveillance for viral hepatitis through NNDSS is based on case definitions developed and approved by the Council of State and Territorial Epidemiologists (CSTE) and CDC. Reported cases of acute viral hepatitis A are required to meet specific clinical and laboratory criteria. Estimated infections are based on laboratory-confirmed reports of acute viral hepatitis. Hepatitis A is reportable in all jurisdictions. Health-care providers, hospitals, and/or laboratories report cases to the local or state health department, and states voluntarily submit reports or notify CDC of newly diagnosed cases of hepatitis A that meet the surveillance case definition. To account for under-ascertainment and under-reporting, the number of reported cases is multiplied by 2.0. The methods for developing the multiplication factor are documented in Klevens, et al (2) with corrected multipliers developed by CDC (1).

Goal Setting: The 2025 goal of 4,000 estimated infections is consistent with CDC’s Division of Viral Hepatitis 2025 Strategic Plan. Annual targets assume a constant (linear) rate of change from the observed baseline (2017 data year) to the 2025 goal (2023 data year).

Limitations: The number of estimated infections is based on a simple, probabilistic model for estimating the proportion of patients who were symptomatic, received testing, and were reported to health officials in each year (2). This constant multiplier may not account for variations over time in under-reporting and under-ascertainment due to public and provider awareness, changes in laboratory and diagnostic techniques, and changes in the definition of the condition.

References

1. Centers for Disease Control and Prevention. Viral Hepatitis Surveillance—United States, 2018. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention; 2020. Available at: https://www.cdc.gov/hepatitis/statistics/2018surveillance/pdfs/2018HepSurveillanceRpt.pdf.
2. Klevens RM, Liu S, Roberts H, Jiles RB, Holmberg SD. Estimating acute viral hepatitis infections from nationally reported cases. Am J Public Health. 2014;104(3):482-7.