Statewide Increase in Hepatitis C Virus Vertical Transmission Found

fetus in an ultrasound
fetus in an ultrasound
State medical surveillance data suggest that the risk for mother-to-infant vertical transmission of hepatitis C virus is increasing.

According to the results of a study published in Morbidity and Mortality Weekly Report, the rate of hepatitis C virus (HCV) infection among pregnant women enrolled in Wisconsin Medicaid is rising. Further, approximately two-thirds of infants born to women with HCV during pregnancy were not tested for HCV according to recommendations.

To determine the proportion of pregnant women with HCV, researchers examined HCV-positive laboratory tests using Wisconsin Department of Health Services and Wisconsin Medicaid encounter data for 146,267 women who delivered at least one infant between 2011 and 2015.

Vertical transmission risk was assessed as high (evidence of viremia during pregnancy), possible (evidence of viremia before pregnancy), and unknown (anti-HCV antibody positive but no RNA results). To estimate the frequency of HCV testing for infants at high risk for vertical transmission, researchers assessed guideline-concordant testing among infants who were enrolled in Medicaid to at least 18 months of age.

A total of 608 women (0.4%) had documented HCV infection prior to delivery. Of those women, 180 (30%) were considered high risk, 151 (25%) were considered possible risk, and 277 (46%) had unknown risk. The rate of HCV infection among pregnant women increased by 93% between 2011 and 2015 (2.7 vs 5.2 per 1000).  

In an email interview with Infectious Disease Advisor, Theresa Watts, RN, MPH, a doctoral nursing student at the University of Wisconsin-Madison and lead author on the study, stated that the results, “are consistent with other studies” in other regions of the United States.

For the infants born with a high risk for vertical transmission, 50% were enrolled in Medicaid for at least 18 months. Of these, 34% were tested for HCV according to recommendations. Vertical transmission was reported for 4% of the infants considered to have a high risk for transmission.

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Ms Watts concluded that the study results, “show how the consequences of the national opioid epidemic go beyond overdoses and addiction, to increases in transmission and infection of a serious but preventable disease. Further, the consequence of not treating women of childbearing age for hepatitis C can potentially affect the next generation through the passing of the virus from mothers to babies.”


Watts T, Stockman L, Martin J, Guilfoyle S, Vergeront JM. Increased risk for mother-to-infant transmission of hepatitis C virus among Medicaid recipients – Wisconsin, 2011-2015. MMWR Morb Mortal Wkly Rep. 2017;66:1136-1139.