Hepatitis C virus infection in spouses: sexual transmission or common exposure to the same risk factors?

OBJECTIVES: The aim of this study was to evaluate whether the transmission of hepatitis C virus (HCV) between spouses occurs through sexual contact or through other types of exposure. METHODS: We consecutively enrolled 311 chronic HCV carriers and their spouses. The spouses underwent HCV blood testing. Exposure to parenteral risk factors was compared between couples of which both partners were HCV positive and couples with one positive partner. In couples with both partners positive, qualitative detection of serum HCV RNA and genotyping were performed. RESULTS: The prevalence among spouses was 10.3% (32/311). The mean age was higher for HCV-positive spouses (57.7 vs 49.6 yr for HCV-negative spouses; p < 0.01). The prevalence among spouses increased with the duration of marriage, whereas no difference was found in relation to the clinical status of the index case. The 32 HCV-positive spouses reported parenteral exposure (blood transfusion, drug use, and use of multiple-use glass syringes inside or outside the family) more often than the 279 HCV-negative spouses (84.4% vs 26.2%; odds ratio [OR], adjusted for age by multiple logistic regression analysis, 12.4; 95% CI = 4.5-34.0). The percentage of couples sharing glass syringes was significantly higher among those with both partners infected (65.6% vs 12.9%; OR = 12.9; 95% CI = 5.4-31.4). Qualitative serum HCV RNA was determined in 22 couples with both partners infected; in 13 of them, both partners were HCV RNA positive, whereas in the remaining nine, only one partner was positive. In eight of the 13 couples with both partners HCV RNA positive, the same genotype was found for both partners. CONCLUSIONS: The findings that the same genotype was detected for both partners in relatively few couples, and that a history of parenteral exposure was an independent predictor of HCV positivity, suggest that the risk of sexual transmission is low. The sharing of glass syringes may have played an important role in transmission between spouses.