Children with neonatal abstinence syndrome and their mothers represent an underserved at-risk population for HCV infection

Guidelines recommend hepatitis C virus (HCV) screening for pregnant women and for children of HCV-viremic mothers. While the Austrian routine prenatal care program comprises screening for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infection, HCV testing is not included. We assessed viral hepatitis/HIV testing practices, prevalence, and vertical transmission among an at-risk population in Vienna. Children treated for neonatal abstinence syndrome, indicative of maternal substance use (SU) during pregnancy, at our tertiary care center 01/2014–01/2025 and their mothers were included. Pregnancy details, mode of delivery, and demographic/socioeconomic/virologic parameters were retrospectively assessed. Our pediatric cohort comprised 243 children including 5 sets of twins (male: 50.2%; median gestational age: 39 weeks; caesarean section: 45.5%). We included 238 corresponding mothers (median age:30 years) with 88.1% taking opioid agonist therapy. Among those with available data, 10/211(4.7%) were HIV-Ag(+) and 4/237(1.7%) were HBsAg(+). Overall, 227(95.4%) received HCV testing: Of 218 undergoing HCV serology, 116(53.2%) were antiHCV(+), 110 of whom underwent HCV-RNA PCR. Additionally, 9 women received HCV-RNA PCR without prior HCV serology. In total, 53 HCV-viremic mothers were identified. Of the 55 children born to the 53 HCV-viremic mothers, 42(76.4%) underwent HCV-RNA PCR with 4 showing HCV viremia (estimated vertical HCV transmission rate:9.5%). Additionally, 1/7(14.3%) children born to antiHCV(+) mothers who were not tested with HCV-RNA PCR was repeatedly HCV-viremic since birth, suggesting undiagnosed maternal HCV viremia and consecutive vertical transmission. HCV screening was well-established among pregnant women with SU, yet 7.1% did not receive adequate HCV testing. The vertical transmission rate was substantial in viremic mothers and in 23.6% of perinatally HCV-exposed children, HCV status was not assessed - calling for HCV reflex testing in the Austrian routine prenatal care program.