Non-Parenteral Transmission of Hepatitis C Virus

Sir: Hepatitis C virus (HCV)has been~hownto be the major aetiologicagent in post-transfusional non-A non-B hepatitis (NANBH), and 60-70% of haemophiliacs, 48-70% of intravenous drug users (~':Js) and 20% of haemodialvsis patients have ,?,tibodIe.s to HCV (anti-HCV)1-3. Nevertheless, since an~­ HCV has been also found in patients with ~hrornc hepatitis cirrhosis or hepatocellular carcinoma, without any previous blood transfusion3s, routes of transmission other than blood-borne or parenteral have been suggested. Although several reports have shown that both sexual and casual (non sexual contacts) can transmit HCV infection, others did not confirm these results3,6,7. In our setting IVDUs are a major reservoir for HCV infectionr, therefore heterosexual partners and household contacts of infected patients can be a population at particular risk for acquiring the infection. To compare the prevalence rates between populations at different theoretical ~CV exposure levels, three groups have been studied: a group of IVDUs a cohort of both sexual and non-sexual contacts of this group and a sample of volunteer blood donors as control group (Table 1). . Sera from all participants were tested for antiHCV using the Ortho Diagnostics Sy~tem .enzy.me immunoassay1. Demographic and epidemiological data from the NDUs' contacts was collected by means of a standardized questionnaire. Prevalences between groups, were tested using a two-sided z-test for proportions. Table 1 shows the prevalence and characteristics for each group studied. Non-sexual contacts were persons living with the index cases (IVDUs), mcluding 40 parents (48.8%), 34.brothers (42.5~), two sons (2.4%) and six cases With another family tie (7.3%). Neither sexual nor household contacts differed from blood donors with regard to their HCV prevalence (P=O.06 and P=O.4 respectively), IVDV being the only group with a higher HCV prevalence than controls (P<O.OOOl). Nevertheless, while the estimated relative risk (with respect to the control group) for non-sexual contacts is 0.9, for sexual partners it is 3.1. The high risk of infection among partners suggests that significant results might be found if a bigger sample size were studied. Finally, although our results are similar to other local reports with regard to both blood donors and IVDUs' HCV prevalence rates, they do not confirm the association between household contacts and HCV infectiorr'-". Assessment of transmission risk from family members' prevalence rates may be affected by several biases. They usually share the same socio-economic status and they may therefore have similar risk behavioural patterns. Therefore, infection from sources other than casual contact is possible. We conclude that while non-sexual HCV household transmission is unlikely, HCV infection may be transmitted at low rates by heterosexual intercourse. Nevertheless, further studies including demographic and behavioural data from controls and non-sexual contacts are needed for a better assessment of the possible risk factors involved. JTorI R Mugal J Casabona? A PujoF V Sorianol M Sabria! lInfectious Diseases Unit and 2Blood Bank Unit Hospital de Badalona "Germans Trias i PUjol." Universitat Autonoma de Barcelona, Barcelona, Spam