Sexual transmission of Hepatitis C Virus infection in a heterosexual population: A systematic review [version 1; peer review: 2 approved]

Background: Hepatitis C virus (HCV) infection is an important cause of liver disease worldwide. Identification of risk factors can guide screening and prevention. Sexual transmission in monogamous heterosexual relationships is rare but it is uncertain which sexual behaviours are linked to HCV transmission. This review aimed to determine risk factors for sexual HCV transmission in heterosexuals in low HCV prevalence countries (PROSPERO registration CRD42016051099). Methods: We searched Medline, Embase, Science Citation Index-Expanded, Social Sciences Citation index, Conference proceedings (Web of Science), CINAHL, Scopus, LILACS, PubMed, and grey literature (04/11/2016). We included studies published in/after the year 2000 that examined sexual risk factors for HCV infection, other than interspousal transmission, in heterosexual adults (≥18 years). We excluded prisoners, people who inject drugs (PWIDs), people co-infected with HIV or from high prevalence countries. Two reviewers completed study selection, data extraction, risk of bias and quality of evidence assessment (GRADE) independently. Meta-analysis could not be conducted. Results: Eight studies were included, examining seven factors (multiple sex partners, receiving/providing sex commercially, PWID partner, and unprotected vaginal, oral, anal sex). None were significant, except the evidence for the factor having a PWID partner was conflicting. Conclusions: We are uncertain about the results due to the very low quality of evidence (GRADE). A more liberal approach to review inclusion criteria might be useful in further identifying factors associated with an increased risk of sexual transmission of HCV infection in a heterosexual population. However, caution should be applied to avoid the impact of confounders on the findings.