Risk of perinatal HCV transmission
Approximately 1% to 8% of pregnant women worldwide are infected with HCV.10 In the United States, 1% to 2.5% of pregnant women are infected.11 Of these, about 6% transmit the infection to their offspring. The risk of HCV vertical transmission increases to about 11% if the mother is co-infected with HIV.12 Vertical transmission is the primary method by which children become infected with HCV.13
Several risk factors increase the likelihood of HCV transmission from mother to child, including HIV co-infection, internal fetal monitoring, and longer duration of membrane rupture.14 The effect that mode of delivery has on vertical transmission rates, however, is still debated, and a Cochrane Review found that there were no randomized controlled trials assessing the effect of mode of delivery on mother-to-infant HCV transmission.15
Serology and genotyping used in diagnosis
The serological enzyme immunoassay is the first test used in screening for HCV infection. Currently, third- and fourth-generation enzyme immunoassays are used in the United States.16 However, even these newer serological assays cannot consistently and precisely distinguish between acute and chronic HCV infections.17 After the initial diagnosis is made with serology, it usually is confirmed by assays that detect the virus's genomic RNA in the patient's serum or plasma.
The patient's HCV genotype should be identified so that the best treatment options can be determined. HCV genotyping can be accomplished using reverse transcription quantitative polymerase chain reaction (RT-qPCR) amplification. Three different RT-qPCR assessments usually are performed using different primers and probes specific to different genotypes of HCV. While direct sequencing of the HCV genome also can be performed, this method is usually not used clinically due to its technical complexity.16
Modern treatments are effective
Introduced in 2011, direct-acting antiviral therapies are now the recommended treatment for HCV infection. These drugs inhibit the virus's replication by targeting different proteins involved in the HCV replication cycle. They are remarkably successful and have achieved sustained virologic response (SVR) rates greater than 90%.11 The World Health Organization recommends several pangenotypic (that is, agents that work against all genotypes) direct-acting antiviral regimens for the treatment of chronic HCV infection in adults without cirrhosis (TABLE 1).18,19
Unfortunately, experience with these drugs in pregnant women is lacking. Many direct-acting antiviral agents have not been tested systematically in pregnant women, and, accordingly, most information about their effects in pregnant women comes from animal models.11
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