How Do We Better Estimate Hepatitis C Prevalence?

Surveillance of the Hep C Virus

By Carol Smyth, MD & Brian Saindon

 

Last week we shared with you the first blog in our series on Hepatitis C prevalence, which explored the mystery behind unreported Hepatitis C cases.  If you haven’t read it yet, check it out here.  This week we’re focusing on surveillance of the Hepatitis C Virus (HCV), and the role it plays in monitoring, treating, and eradicating HCV.

To better understand the prevalence of HCV in the US, our team of experts is conducting an analysis of HCV+ patients within Medivo’s lab test database.  Our investigation will identify patients that have been diagnosed, as well as those that may not have been, which will enable healthcare professionals to identify where treatment is needed and implement education programs to increase testing and improve patient health.

 

Why does HCV surveillance matter?

Surveillance for HCV is extremely important in order to track how many Americans are infected, to develop and fund plans to treat them, and to provide public programs to educate about the virus. The Centers for Disease Control and Prevention (CDC) estimate that about 3.5 million Americans are infected with HCV, but between 50% and 80% of those infected do not know it. A person who does not know they are infected cannot seek treatment, and that has serious implications. A study of HCV+ people in New York found that those with HCV die about 18 years earlier than those who are not infected with HCV.

 

What is going on with HCV surveillance?

Let’s start with the best possible news ― it is possible to eliminate HCV in the US, according to a 2016 report from the National Academies of Sciences, Engineering, and Medicine. The bad news: the report’s authors say that it would take “considerable will and resources” to bring the number of HCV cases to zero. The report authors also say that currently, “viral hepatitis is not a well-funded target for public health surveillance. The CDC only funds seven jurisdictions for comprehensive viral hepatitis surveillance.” Outside of the seven geographic areas funded ― five states (Florida, Massachusetts, Michigan, New York, and Washington) and two cities (Philadelphia and San Francisco)  ―  the current national surveillance system for HCV infection relies on individual states reporting new cases to the CDC, using strict definitions of what constitutes a case. Through the CDC’s National Notifiable Diseases Surveillance System (NNDSS), cases of HCV are reported electronically each week by state and territorial health departments.  However, case reports of HCV are lost for various reasons at points along the reporting chain. For example, cases are often not reported to state departments of health by medical professionals. Among those that are reported at the state level, not all are reported by state health departments to the CDC.

Part of the problem is how a case of HCV is defined. The CDC requires that an acute case (a recently infected person not previously known to have HCV) is defined using both symptoms and lab tests. Because most individuals with HCV don’t have symptoms early in the disease, or have symptoms that look like the flu, this group may not even go to be tested for the infection. The CDC definition of a chronic case of HCV relies on lab test results, but reports of this group may be lost along the reporting chain.
Another problem is that HCV surveillance is underfunded. AmFAR estimates that the CDC has about $1 to spend per identified case of HCV. Hepatitis C is rarely viewed on its own when budgeting is discussed – it is usually combined with hepatitis A and B, very different diseases. The New York State Hepatitis C Coalition, composed of patient advocacy groups, has called for New York State to increase its current annual HCV budget from $2 million to $8 million per year, in order to increase funding for surveillance, prevention and education programs.

hepatitis c prevalence hidden epidemic

 

How many cases of HCV are lost to surveillance?

A recent study found that the Massachusetts state health department had reports of up to 80% of new cases of hepatitis C in the state between 2001 and 2011, however, only 1% of these cases were reported to the CDC during those years. Researchers from the National Institutes of Health noted several reasons for the small number of HCV cases reported to the CDC, concluding that “Incomplete clinician reporting, problematic case definitions, limitations of diagnostic testing, and imperfect data capture remain major limitations to accurate case ascertainment despite automated electronic laboratory reporting.”

 

What efforts have been made to improve HCV surveillance?

In order to develop a more accurate picture of HCV cases nationwide, the CDC started using an estimation method for HCV cases in 2011, which is helping to better estimate the number of Americans with HCV. In 2014, a total of 2,194 cases of acute hepatitis C were reported to CDC from 40 states. After adjusting for under-ascertainment and under-reporting using the new estimation method, the CDC concluded that an estimated 30,500 acute hepatitis C cases occurred in 2014 – considerably higher than the 2,194 case reports received by the CDC from the state health departments.

The first step in effective surveillance of HCV is a plan for capturing cases at the state level. In 2009, the New York State Department of Health (NYSDOH) published such a plan, the “Viral Hepatitis Strategic Plan 2010 – 2015.” The goals of the plan included securing adequate resources for HCV surveillance, improving capacity for case reporting by health professionals and labs, and using surveillance data to better inform HCV prevention programs. The NYSDOH has published statewide HCV data, which our team at Medivo will use to compare with the New York state data from our database in order to see how rates of HCV cases reported in the state compare to those available in the Medivo database.

 

This is the second blog in a five part series. We invite you to follow us through our study over the next month. In our next blog post, we will report on the methods we used in our study of HCV cases in the Medivo database, and comparing this data to published data. We welcome your thoughts and feedback on this project. Please comment below, or reach out to us at info@medivo.com.

 

Footnotes:
  1. Clinical Infectious Diseases, Vaccines Virtual Collection. Deaths Among People With Hepatitis C in New York City, 2000-2011. Available at:  https://cid.oxfordjournals.org/content/58/8/1047.full
  2. New York State Hepatitis C Coalition. 2016 State Budget and Legislative Platform. Available at: https://hepfree.nyc/check-out-the-nys-hep-c-coalition-legislative-platform/
Reading List:
  1. CDC, Surveillance for hepatitis C – United States, 2014. Available at https://www.cdc.gov/hepatitis/statistics/2014surveillance/commentary.htm#bkgrndC
  2. University of Washington. Hepatitis C online. Available at: http://www.hepatitisc.uw.edu/pdf/screening-diagnosis/epidemiology-us/core-concept/all
  3. Onofrey S, Aneja J,  Haney GA et al. Underascertainment of acute hepatitis C virus infection in the US surveillance system: a case series and chart review. Ann Intern Med. 2015;163:254-261. Available at: http://www.ncbi.nlm.nih.gov/pubmed/26121304
  4. NY State Department of Health HCV surveillance plan, 2009. Available at: https://www.health.ny.gov/publications/1862.pdf
  5. National Academies of Sciences, Engineering and Medicine report: Eliminating the Public Health Problem of Hepatitis B and C in the United States: Phase One Report (2016). Available at: https://www.nap.edu/read/23407/chapter/2#11=

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