Increased Risk for Mother-to-Infant Transmission of Hepatitis C Virus Among Medicaid Recipients - Wisconsin, 2011-2015

Abstract

State surveillance during the last 10 years reveals a nationwide increase in hepatitis C virus (HCV) infection among young adults (1). The proportion of infants born to HCV-infected women is also increasing nationally (2). To estimate the proportion of infants born to HCV-infected women and the frequency of confirmed HCV infection in their infants, maternal name and date of birth from HCV reports in the Wisconsin Electronic Disease Surveillance System (WEDSS) were linked to Wisconsin Medicaid data for 2011-2015 births. During this period, in the Wisconsin Medicaid population, the proportion of women who had evidence of HCV infection during pregnancy increased 93%, from 1 in 368 pregnancies to 1 in 192. Among 183 infants born to women with evidence of HCV viremia during pregnancy, 34% received recommended HCV testing (3). Mother-to-infant (vertical) transmission was documented in 4% of infants. Improvements in HCV screening practices among pregnant women and infants could enhance identification of infants at risk for vertical transmission of HCV.

FIGURE 1

Classification of vertical transmission risk based on hepatitis C virus (HCV) infection status among Medicaid recipients — Wisconsin Electronic Disease Surveillance System and Wisconsin Medicaid data, Wisconsin, 2011–2015 Abbreviation: Ab = antibody. * Women with an HCV infection reported before their date of delivery were categorized into three risk groups: women who had evidence of viremia (RNA-positive) during pregnancy (high risk), women who had evidence of viremia before pregnancy but did not have RNA results during pregnancy (possible risk), and women who were anti-HCV antibody-positive but did not have viremia results (unknown viremic risk).

FIGURE 2

Proportion of pregnant Medicaid recipients with evidence of hepatitis C virus (HCV) infection before delivery, by risk category — Wisconsin Electronic Disease Surveillance System and Wisconsin Medicaid data, Wisconsin, 2011–2015 * Unknown viremic risk = anti-HCV antibody-positive, but no viremia (RNA) results available; Possible risk = evidence of viremia before pregnancy, but no RNA results during pregnancy; High risk = evidence of viremia (RNA-positive) during pregnancy.