July 8, 2021 – A simpler version of a test for hepatitis C virus (HCV) could open the tests to people in areas where medical care is limited.
“While such a test is not yet developed, it could be groundbreaking and have a significant impact on the feasibility and cost of HCV elimination, especially in low- and middle-income countries,” said Madeline Adee, MPH, of Massachusetts General Hospital in Boston.
Adee and her fellow researchers have suggested that a simple and cheap – but less accurate – test for HCV infection could identify more people who are in less affluent countries or areas of the US where medical laboratories are few infected with HCV and should be treated.
A silent killer
Hepatitis C infects the liver and can go undetected 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 get tested for hepatitis C infection at least once. Tests are especially important for people who had a blood transfusion before July 1992 (when blood tests for hepatitis infections started) or who had blood from a donor who later tested positive for HCV, the federal agency says. Tests are also recommended for people with liver problems and for medical staff, first aiders, or others who may have been exposed to HCV infected needles.
HCV can be detected with a blood test to look for antibodies to the virus. However, more than 1 in 5 people who test positive using this method may have a false positive, which means that there is no virus in their body.
A more accurate HCV test measures the amount of hepatitis virus (HCV RNA) genetic material in a patient’s blood. This test is almost 100% accurate but needs to be analyzed in a high quality clinical laboratory.
Once HCV is diagnosed, infected people can be closely monitored by their doctors, and those in need can be treated with antiviral drugs and usually cured over an 8 to 12 week course.
Lack of testing laboratories
With few or no medical laboratories available in some underdeveloped countries, as well as geographically isolated areas of the United States, the research team came up with a simple solution: They suggested using a simple and inexpensive blood test that looks for antibodies that look to HCV -Core and not about the genetic material of the virus.
Hepatitis C has a central core and a surrounding envelope. In people infected with HCV, the immune system makes antibodies against the nucleus. These antibodies are often not strong enough to fight off infection, but their presence in the blood is a strong sign of possible infection.
According to the current standard of care, people who have a positive result on an antibody-based rapid diagnostic test (RDT) for HCV infection can confirm the results with laboratory-based RNA tests.
Instead, Adee and co-researchers suggested that people who have an antibody test that indicates possible infection could be retested with a core antigen-based rapid test. People with uncertain core antigen test results could then have laboratory-based RNA tests done to confirm or rule out infection. Patients who tested positive for the core antigen test could begin treatment without the need for additional, expensive RNA tests.
To see if this approach could work, the researchers created a theoretical mathematical model and applied it to two nations with high HCV infection rates: the Republic of Georgia, where an estimated 5.4% of the population has HCV infections, and Malaysia, where an estimated 1.5% of the population are infected. (In context, about 1% of the US adult population lives with 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-based RNA testing.
For Malaysia, the proposed method would increase diagnosis rates from 57.0% to 91.2%.
The cost savings, mainly from avoiding the cost of care for patients with HCV over the age of 50, would be $ 232,000 per 10,000 people in Georgia and the corresponding savings in Malaysia would be $ 504,000 per 10,000 people, Adee and 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 treatment follow?
The suggested testing method would likely improve the diagnosis, but whether that would lead to increased treatment is uncertain, says Lesley Miller, MD, who specializes in HCV screening and treatment in underserved populations at Emory University in Atlanta.
“When we talk about hepatitis C, it’s all about the care cascade, the waste at every step from those who have the disease and have not been diagnosed to those who have been tested and only partially diagnosed for not having a confirmed one Infection, for those who are being cared for, treated and cured, ”says Miller, who was not involved in the study.
“It’s about closing the gaps in the care cascade to get rid of the virus, which we are all trying to do,” she says.
In the United States, there are certain risk groups who could benefit from such a system, says Miller, using the example of people who consume injectable drugs.
“These people often have less access to traditional care, so it’s really important to get quick testing and care to where these people are. So if we can use mobile units in areas with high prevalence and do this at the point of care, that simplifies the whole process, ”she says.
Thomas J. Hoerger, PhD, Senior Fellow in Health Economics and Finance at the nonprofit research group RTI International in Research Triangle Park, NC, says the model proposed by Adee and colleagues could skip the testing step that would require patients to return to to confirm their diagnosis.
“People don’t always come back for more tests. So if you 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 high treatment costs, 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 how sensitive the core antigen rapid test is, how much the cost is compared to the HCV RNA test, and whether better availability the rapid test would lead to an improvement afterwards.
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