Current guidelines recommend that infants born to women with hepatitis C (HCV) viremia are screened for HCV antibody at age 18 months, and if positive, referred for RNA testing at 3 years to confirm chronic infection. This policy is based in part on analyses suggesting 25%-40% of vertically acquired HCV infections clear spontaneously within 4-5 years.
Data on 179 infants with HCV RNA and/or anti-HCV evidence of vertically acquired infection in three prospective European cohorts were investigated. Ages at clearance of infection were estimated taking account of interval censoring and delayed entry. We also investigated clearance in initially HCV RNA negative infants in whom RNA was not detectable until after 6 weeks.
Clearance rates are initially high then decline slowly. Apparently, many infections clear before they can be confirmed. An estimated 65.9% (50.1-81.6) of confirmed infections cleared by 5 years, at a median 12.4 (7.1-18.9) months. If treatment began at age 6 months, 18 months or 3 years, at least 59.0% (42.0-76.9), 39.7% (17.9-65.9), and 20.9% (4.6-44.8) of those treated would clear without treatment. In seven (6.6%) confirmed infections, RNA was not detectable until after 6 weeks, and in 2 (1.9%) not until after 6 months. However, all such cases subsequently cleared.
Most confirmed infection clears by age 3 years. Treatment before age 3, if it was available, would avoid loss to follow-up, but would result in substantial over-treatment.

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