High-risk sexual behavior, body piercing, intramuscular injection, and vaccine inoculation abroad, and having lived aboard for >3 months were significantly associated with hepatitis C virus (HCV) in blood donors with otherwise nonidentifiable source of infection. This according to a recent study that examined the prevalence of HCV and its associated factors in healthy adults without identifiable route of transmission. 91 HCV-infected donors were identified in 2014-2016, of whom 46 were recruited in a mixed-method study to examine their transmission routes. Researchers found:

• 75% of recruited donors were HCV RNA positive, with the predominant subtypes being 1b and 6a.
• Only 14 (30%) recruited donors could be traced to past history of contaminated blood transfusion or injection drug use.
• High-risk sexual behavior, body piercing, intramuscular injection, and vaccine inoculation abroad, and having lived aboard for >3 months were significantly associated with hepatitis C virus (HCV) in case-control analyses.