Should all pregnant women in the US be screened for hepatitis C?
In August, the U.S. Preventive Services Task Force issued a draft recommendation that encourages clinicians to screen all adults aged 18 to 79 years for HCV infection, including pregnant women. According to the USPSTF, HCV prevalence doubled among women aged 15 to 44 years between 2006 and 2014. Due to the increasing prevalence of the disease in this age group, the task force said clinicians “may want to consider screening pregnant persons aged younger than age 18 years.”
Infectious Disease News asked Jordan J. Feld, MD, MPH, the R. Phelan Chair in Translational Liver Disease Research at the University of Toronto, and Anna Suk-Fong Lok, MD, professor of gastroenterology, hepatology and internal medicine at the University of Michigan, about the importance of universal HCV testing in pregnant women and why physicians may argue against it.
The primary arguments for screening for a disease are usually that it will not be diagnosed without screening, it is reasonably common and there is a clear intervention for those who test positive. At first glance, one might then assume that screening all pregnant women for HCV does not make a lot of sense. Studies have documented low HCV prevalence among pregnant women, and with no approved therapy to prevent transmission, what would be the rationale?
The rationale for screening pregnant women goes beyond HCV. The standard approach to HCV screening in pregnancy is to test those with an identifiable risk factor. Risk-based screening has never proven effective, but this approach utterly fails in pregnant women.
One study presented at the Liver Meeting in 2018 highlighted this issue. Norton Healthcare in Louisville, Kentucky, moved from risk-based to universal HCV screening for pregnant women. Of just over 10,000 women in prenatal care, about 1,000 were deemed “at risk” and were offered HCV testing between 2014 and 2015. The prevalence among this “at-risk” population was 4.3%. When they went on to prospectively perform universal testing on 9,033 women between May 1, 2016, and Dec. 31, 2017, the prevalence in this cohort was a striking 4.9%.
To be clear, they tested 10 times as many women, and the chance of a positive test increased. It is assumed that when one moves to universal testing, the prevalence will go down even if you identify more total cases. The fact that the prevalence increased makes this study perhaps the best example of why risk-based screening is problematic.
The argument for risk-based screening is that it makes intuitive sense. Why would you test people who are not at risk for having the condition? The problem is that we are terrible at assessing who is at risk. Had the Louisville clinic continued with risk-based testing, only about 45 of the women who tested positive would have been identified. It is hard to say why we are bad at assessing risk, but it likely relates to our inherent biases about who and how we ask about risk factors.
If HCV testing is normalized as part of routine prenatal care, like HIV, hepatitis B and other prenatal tests, there will be no reluctance to getting the test done. A positive HCV test is an opportunity to explore risk factors for HCV acquisition, particularly drug use. This may be the gateway to getting women assistance at managing drug use during pregnancy, which has more immediate benefits than the diagnosis of HCV itself. For some women, prenatal care may be one of their few interactions with the health care system. Diagnosing HCV can prevent silent progression of liver disease and other complications. Furthermore, a mother’s diagnosis should lead to testing the child, particularly now that we have increasing evidence of the efficacy and safety of HCV treatment in children and adolescents.
Testing pregnant women for HCV is good public health policy. The AASLD/IDSA has supported this approach, which needs to be adopted if we are going to continue on the path to elimination.
- USPSTF. Hepatitis C: Screening. https://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/hepatitis-c-screening. Accessed September 25, 2019.
Disclosure: Feld reports receiving research support from Abbvie, Gilead Sciences, Janssen and Wako/Fujifilm and consulting for Abbott, Abbvie, Gilead, Enanta and Roche.
Some have argued against HCV screening for pregnant women because there are currently no specific measures that can be taken to interrupt mother-to-child transmission other than avoiding invasive procedures. Further, there are no antivirals with established safety to cure pregnant women before delivery.
Others have worried about the cost of screening. However, cost of HCV antibody testing is low, and pregnant women are already screened for many infections, such as HIV, hepatitis B and rubella.
There is also concern that those who test positive may not seek care and treatment after the babies are born. However, rather than no screening, the solution should be to link these women to HCV care during their return obstetrics care visits or when they bring their babies in for well-baby check-ups.
Although there is no vaccine available to prevent HCV infection in newborns and the currently available direct-acting antivirals have not been demonstrated to be safe for use during pregnancy, risk for transmission may be reduced by avoiding use of invasive procedures, such as fetal scalp monitoring. Also, evaluation of liver disease in pregnant women with HCV may identify the small percentage of patients with cirrhosis who should be referred to gastroenterologists or hepatologists for liver care as well as specialists in maternal-fetal medicine for coordination of obstetrics care.
Many young people do not seek medical care unless they have symptoms. Pregnancy is an opportune time for detection of asymptomatic medical conditions that can progress if left untreated. HCV is unique in that we currently have simple, safe and highly successful treatment — oral therapy for 8 to 12 weeks with a 97% to 98% chance of cure. Timely detection and linkage to care will allow infected women to be treated and cured after their babies are born, and it will also reduce the number of children infected with HCV.
- USPSTF. USPSTF. Hepatitis C: Screening. https://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/hepatitis-c-screening. Accessed Sept. 25, 2019.
Disclosure: Lok reports receiving research grants from Bristol-Myers Squibb and Gilead to the University of Michigan and has served on an advisory board for Gilead.
Editor's note: To read our December cover story, click here.