Hepatitis C virus (HCV) is the most common bloodborne infection in the United States. In 2014, it than any other infectious disease. from 2010 to 2016.
Yet despite the high prevalence of HCV, the CDC estimates that about half of people living with the virus don't know they're infected.
"We are doing a very bad job identifying hepatitis C right now," Nancy Reau, MD, section chief for hepatology at Chicago's Rush University Medical Center, told 番茄社区.
Several factors underlie the low HCV testing rates, but some clinicians argue that overly-cautious screening guidelines are the major one. In recent years, this increasingly vocal group has been advocating for universal HCV testing -- akin to recommendations for HIV, in place since 2oo6. Today, are thought to be aware of their status.
Hepatitis C is a different story. Until recently, doctors had been reluctant to screen for a slow-moving illness for which there wasn't a very effective cure. Current testing guidelines reflect that cautious approach, recommending "risk-based" screening for patients most likely to have been exposed to the virus.
"We've seen that risk-based screening tends not to be enough. We saw it with HIV and we've seen it with hepatitis C in certain populations," said Rachel Epstein, MD, an infectious disease fellow at Boston Medical Center.
"There is a groundswell of discussion, and most of it seems to be in favor of universal testing," said Marc Ghany, MD, staff physician at the National Institute of Diabetes and Digestive and Kidney Diseases' liver disease branch. But there are still many doctors who say "it's still not ready for prime time," Ghany added.
The merits of universal testing will be debated at the American Association for the Study of Liver Diseases (AASLD) annual meeting this week, according to Vincent Lo Re, MD, an infectious disease specialist at the University of Pennsylvania in Philadelphia. Lo Re serves on the AASLD's hepatitis C guidance panel.
Critics caution it will be expensive to start testing everyone for HCV, and that changing the guidelines will create an additional burden for time-strapped primary care physicians. But proponents argue that there's enough data to support the idea that universal screening would not only save lives, but also ultimately save money for health systems by catching HCV infections before they lead to more serious illnesses, like liver cancer.
Meanwhile, the landscape of hepatitis C has changed dramatically over the past decade, with the opioid epidemic driving a sharp uptick in new infections among young adults. And, starting in late 2013, the FDA approved several new antiviral drugs with minimal side effects capable of curing more than 95% of patients. Though the cures were initially expensive, market competition has since driven prices down dramatically.
Collectively, these new developments may tip the scales in favor of a universal testing approach in the near future.
Evolution of HCV screening recommendations
When HCV was discovered in 1989, the CDC quickly issued guidelines that recommended testing for any patient who may have been exposed through blood and organ donation, accidental needle stick, injection drug use, or other risk factor.
But over the following decade it became clear that a risk-based approach wasn't working. By 2012, that between 45% and 85% of adults were not aware of their infection, and that members of the "Baby Boom" generation (those born 1945 to 1965) were six times as likely to be infected compared to any other age group.
That year, the CDC updated its guidance to include blanket "birth cohort" screening -- i.e., a one-time test for everyone born from 1945 to 1965, a.k.a. the Baby Boom generation -- in addition to the prior risk-based screening. The U.S. Preventive Services Task Force (USPSTF) followed suit in 2013.
But since then, Lo Re said, "there has continued to be growing evidence that both birth cohort screening and risk based screening might not be sufficient."
In particular, doctors are worried about a younger generation of American teenagers and young adults part of a driven by the opioid epidemic.
Earlier this year, two major medical societies -- the AASLD and the Infectious Diseases Society of America -- teamed up to issue blanket screening recommendations targeting three new high-risk groups: pregnant women, men who have sex with men, and incarcerated people.
Those recommendations have not been adopted by the CDC or the USPSTF, although both are currently in the midst of a literature review to re-evaluate their respective HCV screening recommendations.
USPSTF Vice-Chair Doug Owens, MD, said he can't predict what new guidance the task force will ultimately adopt, but noted that the calculus has changed since the approval of highly-effective hepatitis C "cures" 5 years ago.
Meanwhile, at the AASLD meeting this this week, Lo Re predicts strong arguments will be put forward for the society to update its guidance in favor of universal testing for everyone.
Pros and cons of universal testing
The arguments against universal testing center around cost, with policymakers worried that testing and treating millions of HCV patients -- many of whom are Medicaid and Medicare recipients -- would decimate government budgets.
"These screening programs are costly because you have to have the staff and infrastructure to be able to do it," said Ghany, noting "HIV receives a lot more funding than HCV." Then there's the matter of treating people who test positive. New hepatitis C drugs are famously expensive, although wholesale prices have .
The cost argument was further undercut by two recent studies ( and ) in which researchers argued a universal screening strategy would be cost effective, offsetting the long-term expense of caring for patients with end-stage liver disease and other health problems caused by HCV infection.
Still others argue that the current screening guidelines are not the problem -- rather, doctors are not following the guidelines that already exist. For example, a that only about one in 10 Baby Boomers has been screened for HCV, despite the fact that blanket testing policies have been in place for that age group since 2012. that only a third of young adults who admitted to opioid abuse were tested for HCV.
If implemented properly, risk-based screening does a good job of identifying patients with HCV, said Ghany.
"The problem," Ghany said, is "there are a lot of barriers to risk-based screening."
Overburdened primary care providers might forget which patients qualify for a HCV test, and stigma associated with the disease means some patients might not admit when they've injected drugs.
A one-time test for everyone would help alleviate both of these barriers, said Epstein, who led the the 2018 study on opioid-addicted young adults. According to Epstein, a universal test would mean physicians wouldn't have to sort out which of their patients qualify, and patients wouldn't feel singled out for being recommended for a test.
One lesson learned from universal HIV screening is that testing everyone "may be associated with less stigma," said Owens.
Unlike Ghany, Epstein believes that risk-based screening in hepatitis C will never be enough, even if done correctly. In an email to to 番茄社区, she wrote, "multiple studies, including ours, demonstrate that of individuals diagnosed with [HCV], anywhere between a substantial minority to almost two-thirds do not have a documented risk factor."
Lo Re takes a more conservative approach, arguing that currently available data probably aren't sufficient to confidently recommend universal screening. It was only 6 years ago, he said, that the CDC included blanket birth cohort screening for Baby Boomers, and the impact of that updated guidance isn't entirely clear.
"The question that drove us in this conversation is, 'Do we have enough evidence at present to warrant one-time universal hepatitis C testing?'" he said. "I think there is evidence out there, but the evidence isn't extensive yet. So the question [becomes], 'How much evidence do you need?' And that's different for different people."
"It's a big lift to advocate for universal screening in the absence of data that the current [birth cohort] screening modalities are not working," Lo Re said. "Before you move forward with broader screening, it is prudent to have these analysis performed."
Even Reau, who agreed it's too soon for universal testing, said it's likely that the screening strategy will be implemented eventually -- after guidelines are expanded to include pregnant women, incarcerated people, and other large swaths of patients.
"They're eventually going to identify so many high-risk groups that pretty soon it's going to be harder to identify the person who doesn't need screening," she said.
"I think it will happen," agreed Ghany. "But when will it happen? I don't have a crystal ball."