July 8, 2021 – A simpler version of a test for the hepatitis C virus (HCV) could open the test to people in areas with limited medical care.
“Although not yet developed, such a test could be a game-changer and have a substantial impact on the feasibility and cost of HCV elimination, especially in low- and middle-income countries,” says Madeline Adee, MPH, of Massachusetts General Hospital in Boston.
Adee and his co-researchers proposed that in less wealthy countries or in areas of the United States where medical laboratories are scarce, the use of a simple and inexpensive – but less accurate – test for infection with HCV could identify more people who are infected with HCV and need to be treated.
A silent killer
Hepatitis C infects the liver and can go unnoticed for many years because it does not always cause symptoms. But long-term HCV infections can lead to scarring of the liver (cirrhosis), liver cancer, liver failure, and other serious medical problems.
The CDC recommends that all adults have at least one test for hepatitis C. The test is especially important for people who received a blood transfusion before July 1992 (when the blood test for hepatitis infections has started) or received blood from a donor who subsequently tested positive for HCV, according to the federal agency. The test is also recommended for people with liver problems and healthcare workers, first responders, or others who may have been exposed to needles infected with HCV.
HCV can be detected using a blood test to look for antibodies against the virus. Yet more than one in five people who test positive with this method may have a false positive result, which means that there is no virus in their body.
A more accurate test for HCV measures the level of hepatitis virus genetic material (HCV RNA) in a patient’s blood. This test is almost 100% accurate, but it should be analyzed in a high quality clinical laboratory.
Once diagnosed with HCV, those infected can be closely monitored by their doctor, and those in need can be treated and usually cured with antiviral drugs over a period of 8 to 12 weeks.
Shortage of testing laboratories
Since some underdeveloped countries, as well as geographically isolated areas of the United States, have little or no medical laboratories, the research team came up with a simple solution: They suggested using a simple blood test. and inexpensive that looks for antibodies. to the nucleus of HCV, rather than to the genetic material of the virus.
Hepatitis C has a central nucleus and a surrounding envelope. In people infected with HCV, the immune system creates antibodies against the nucleus. These antibodies are often not strong enough to fight infection, but their presence in the blood is a strong sign of a possible infection.
Under the current standard of care, people who test positive on an antibody-based rapid diagnostic test (RDT) for HCV infection have their results confirmed with a lab RNA test.
Instead, Adee and his co-researchers proposed that people who have an antibody test showing possible infection could be retested with a rapid test based on the background antigen. People with uncertain baseline antigen test results could then undergo laboratory RNA tests to confirm or rule out infection. Patients who test positive for the central antigen test could start treatment without the need for additional and expensive RNA tests.
To see if this approach could work, the researchers created a theoretical mathematical model and applied it to two countries with high rates of HCV infection: the Republic of Georgia, where an estimated 5.4% of the population is infected with HCV, and Malaysia, where an estimated 1.5% of the population is infected. (For the background: about 1% of the U.S. adult population lives with an HCV infection, according to the CDC.)
Applying the proposed method to the Republic of Georgia would result in a diagnosis rate of 95.4%, compared to 78.8% for laboratory RNA testing.
For Malaysia, the proposed method would increase diagnostic rates from 57.0% to 91.2%.
The cost savings, primarily by avoiding the costs of care for HCV patients over 50 years, in Georgia would be $ 232,000 per 10,000 people, and the corresponding savings in Malaysia would be $ 504,000 per 10,000 people, Adee and her colleagues calculated.
Their results were presented at the International Liver Conference sponsored by the European Association for the Study of the Liver.
Would an increase in salary follow?
The proposed test method would have the potential to improve diagnosis, but it is not known whether this would result in increased treatment, says Lesley Miller, MD, who specializes in screening and treating HCV in underserved populations. at Emory University in Atlanta.
“When it comes to hepatitis C, it all revolves around the cascade of care, from the fall at every stage of those who have the disease and are undiagnosed, to those who are tested and only partially diagnosed because they are do not. have a confirmed infection, to those who receive care, are treated and cured, ”says Miller, who was not in the study.
“It’s about filling in the gaps in the cascade of care in order to eliminate the virus, which is what we’re all trying to do,” she says.
In the United States, some at-risk populations could benefit from such a system, says Miller, using people who inject drugs as an example.
“These people often have less access to traditional care, so it is very important to bring tests and rapid care where these people are. So if we can deploy mobile units in high prevalence areas and do it at the point of care, that simplifies the whole process, ”she says.
Thomas J. Hoerger, PhD, senior researcher in health economics and financing at the nonprofit research group RTI International in Research Triangle Park, North Carolina, says the model proposed by Adee and colleagues could remove the step tests in which patients would be needed. come back to confirm their diagnosis.
“People don’t always come back for more tests, so if you can do it right away and have the results of a screening test, you may be able to get people to come back faster. You still have the problem of the high cost of the treatment, but that would at least make it a little more convenient, ”he says.
Hoerger, who was not involved in the study, notes that the success of the strategy would depend on the sensitivity of the rapid baseline antigen test, its cost compared to the HCV RNA test, and whether to render the more available rapid test would result in an improvement in follow-up.
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