Development of universal HCV vaccine by coupling HCV NS3 proteins to the surface of liposomes

Even though there is evidence of sexual transmission of HCV the actual risks in different types of sexual behavior have been difficult to assess and it is still unclear as to which factors actually contribute to this route of transmission. “Dry sex”, defined as inadequate vaginal lubrication, may lead to abrasive trauma during intercourse and thus favor sexual transmission of HCV. There are few studies associate long-term relationship with HCV infection and attribute it to repeated sexual exposure over time the current cases indicate that one must consider alterations in vaginal mucosa as a more plausible cause of transmission following dry sex. In this study we report transmission associated with dry sex practice from eleven HCV-infected individuals to their heterosexual partners. Forty female patients with symptomatic acute HCV infection were identified at the Viral Hepatitis Laboratory/Fiocruz/Rio de Janeiro/Brazil. To confirm HCV transmission between spouses, nested RTPCR products were submitted to direct nucleotide sequencing of the NS5B region. The sexual partners subsequently consented to HCV testing and their chronic HCV infection status was confirmed by the detection of HCV antibodies and HCV RNA. The obtained sequences were aligned with corresponding nucleotide sequences of 23 HCV reference sequences retrieved from GenBank and 13 local unrelated HCV sequences and phylogenetic tree was constructed with Mega 4 software using Neighbor-Joining method. The evolutionary distances were computed using the Maximum Composite Likelihood method and their reliability was assessed by bootstrap resampling 1000 replicates. Among the 40 subjects that reported sexual risk behavior, 29 had sexual partners that volunteered samples to investigate possible HCV genomic similarities. Since fourteen subjects had low or undetectable HCV RNA throughout the study follow-up, genotype results were determined using the Murex HCV Serotyping 1–6 assay (Abbott) and all shared similar genotypes with their partners. The phylogenetic analysis of the nucleotide sequence of HCV genome was limited to the remaining 15 subjects and their sexual partners, which revealed nucleotide identity >95% among 14 of the 15 couples, which strongly suggests these partners to be the source of infection, after ruling out possible contamination through personal item sharing. These findings provide strong molecular evidence that the women had acquired HCV infection most likely by interspousal sexual transmission and suggest that guidelines for target populations include education on the potential risk associated with dry sex practices.