Risks of mother-to-infant HCV transmission has increased in Wisconsin

Liz Meszaros, MDLinx | November 21, 2017

In Wisconsin, researchers have found that the incidence of hepatitis C virus (HCV) is steadily increasing in pregnant women, as is the risk of transmission to their newborns. They published their results in Morbidity and Mortality Weekly Report (MMWR) and called for improved screening and management in both groups.

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Hepatitis C virus

Researchers in Wisconsin documented a 93% increase in the number of women on Medicaid who were infected with HCV before delivery, and a 4% rate of mother-to-infant transmission.

Among Wisconsin Medicaid recipients, the rate of HCV infection during pregnancy is increasing, as it is throughout the country. Several factors have contributed this nationwide growth, including the upswing in injectable drug use caused by the opioid epidemic.

From 2011 to 2015 in Wisconsin, HCV in individuals aged 15 to 44 years increased by 81%, from 45.7 to 82.6 per 100,000 population, according to unpublished data from the Wisconsin Division of Public Health, and 43% of these reported cases were in women. Consequently, the number of infants at risk for vertical transmission—mother-to-infant—has also increased.

Nationwide, vertical transmission occurs in roughly 6% of infants born to women with HCV infection, and twice as often in women who are co-infected with HCV and HIV. Currently, no perinatal intervention that can effectively reduce vertical HCV transmission is available.

“Pregnancy and post-pregnancy care might provide an opportune time to test women and link HCV-infected women to HCV care or treatment, because this is a time when a woman might be likely to use health care services,” noted Theresa Watts, MPH, School of Nursing, University of Wisconsin–Madison, Madison, WI, and fellow researchers.

Watts and colleagues conducted this study to estimate the proportion of women enrolled in Wisconsin Medicaid with HCV infection during pregnancy and estimate the frequency of HCV testing and infection in infants born to these women. They calculated the proportion of pregnancies at risk for vertical transmission as the number of pregnancies in Medicaid recipients with evidence of HCV infection compared to all pregnancies in Medicaid recipients.

In all, 0.4% of the 146,267 Wisconsin Medicaid recipients who gave birth from 2011-2015 had evidence of HCV infection before their delivery date. Of these, 30% were classified as high risk (2 with HIV co-infection), 25% as being at possible risk, and 46% as having unknown viremic risk. In addition, 472 women had reported HCV infection after their delivery date.

From 2011-2015, the number of women infected with HCV before their delivery dates increased by 93%, from 1 in 368 pregnancies to 1 in 192 pregnancies. During this time, mother-to-infant transmission was documented in 4% of infants.

The median age of women with HCV viremia during pregnancy was 26 years, and 79% were non-Hispanic white.

Of the 183 infants born to women with HCV viremia during pregnancy, 50% were continuously enrolled in Medicaid for 18 months or more, and 34% were tested for HCV as recommended, most of whom underwent anti-HCV antibody testing before 18 months of age. Of these 31 infants, 7 had at least two RNA tests before reaching 2 months of age.

“As the rate of HCV infection among women of childbearing age continues to increase nationally, practices for screening pregnant women for HCV and for monitoring infants born to HCV-infected mothers should be improved. Enhanced identification through testing all pregnant women with HCV risk factors and improved public health surveillance of infants at risk for HCV vertical transmission will improve identification, detection, and care for HCV-infected women and infants at risk for HCV vertical transmission,” wrote Watts et al.

They noted that the Council of State and Territorial Epidemiologists recently issued a position statement for the reporting and national notification of perinatal HCV infection.

“Adoption of this position statement by state and local health departments, along with enhanced identification of HCV among women of childbearing age, can improve care for HCV-infected women and infants at risk for HCV vertical transmission,” they concluded.

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