Risk factors for hepatitis C virus antibody positivity in blood donors in a low-risk country

Hepatitis C risk factors in Iranian volunteer blood donors: a case-control study

BACKGROUND

In order to evaluate some possible risk factors for the spread of hepatitis C infection a case-control study was undertaken.

METHODS

The study population consisted of first time blood donors referred to the Iranian Blood Transfusion Organization. Enzyme-linked immunosorbent assay and recombinant immunoblot assay anti-hepatitis C virus (HCV) tests were performed for all samples. Risk factors were evaluated using a questionnaire. A stepwise forward logistic regression analysis was used.

RESULTS

The case group consisted of 193 HCV-positive donors, and 196 HCV-negative donors comprised the control group. Transfusion, undergoing endoscopy, extramarital sexual activities, non-intravenous (i.v.) drug abuse, i.v. drug abuse, and receiving wounds at war were found to be independent risk factors of being HCV-positive (Odds ratio: 17, 4, 42.2, 34.4, 52.8 and 5.2, respectively). No apparent risk factors could be demonstrated in 24.5% of the positive cases.

CONCLUSION

This study could be of particular interest because of the low seroprevalence of hepatitis C and the religious culture of the study population. There are certain medical procedures, lifestyle patterns, and customs and cultural matters in Iran that predispose people to a number of HCV risk factors.

Hepatitis C virus and blood transfusion: past and present risks

The risk of HCV transmission by blood and blood products has been greatly reduced since the early 1980's. Selection of non-remunerated donors, donor selection to prevent HIV transmission, initial surrogate testing in some regions, and introduction of anti-HCV testing have all contributed to this. ALT surrogate testing has become obsolete since the introduction of anti-HCV testing. The residual risk of HCV transmission due to donations in the anti-HCV window period at present is about 1 in 100 000 transfusions of cellular products, and transmission of HCV by plasma products treated with modern inactivation methods such as solvent-detergent treatment, has not been reported. Hemovigilance programmes, which are presently being installed, will provide more data on the safety of blood transfusion. Introduction of HCV nucleic amplification technology (NAT) as a quality control of manufacturing pools for plasma products or as a form of blood donor screening by minipools is anticipated in many European countries for the coming year. Given industrial developments, NAT testing of individual blood donations may become available within the next 2 years. HCV NAT testing will further annihilate the residual risk, and the cost-effectiveness will become relatively low in comparison with other public health measures.

Risk factors for acquisition of hepatitis C virus infection in blood donors: results of a case-control study

BACKGROUND & AIMS

Few studies have explored risk factors predicting hepatitis C virus (HCV) infection in blood donors; their results are contradictory. The aim of this study was to evaluate the association between HCV infection and various risk factors in Canadian volunteer blood donors.

METHODS

Four transfusion centers were involved in this case-control study. A total of 267 confirmed anti-HCV-positive blood donors were interviewed along with 1068 seronegative blood donors matched for sex, age, donation site, and date. Information was collected using a structured telephone interview. The main outcome measures were odds ratios (ORs) and 95% confidence intervals (CIs) for various risk factors from univariate and multivariate analyses using conditional logistic regression.

RESULTS

By univariate analysis, 23 variables were associated with anti-HCV positivity. In the final multivariate analysis, only 5 factors remained independently predictive of HCV infection: previous intravenous drug use (OR, 127.5; 95% CI, 26.0-625.0), having lived in a prison or juvenile detention center (56.1; 11.4-275.7), previous blood transfusion (10.5; 4.7-23.2), sexual contact with an intravenous drug user (6.9; 3.1-15.2), and tattooing (5.7; 2.5-13).

CONCLUSIONS

Most blood donors acquire infection by percutaneous exposure to contaminated blood. A role for sexual transmission is suggested by this study.

Transfusion-acquired hepatitis C: the Danish lookback experience. The Danish HCV [hepatitis C virus] Lookback Group

BACKGROUND

In 1996, the Danish National Board of Health recommended hepatitis C virus (HCV) lookback to identify recipients of blood components from donors found to be positive since the implementation of anti-HCV screening in 1991.

STUDY DESIGN AND METHODS

The aim was to accumulate results of the lookback at a national level and to describe the morbidity of the infected recipients. Records of transfusion were identified for at least 10 years back, and recipients still alive were tested for hepatitis C. Those with positive results were referred for clinical evaluation.

RESULTS

A total of 150 anti-HCV-positive Danish donors had donated blood to 1018 transfusion recipients, of whom 288 (29%) were still alive. Because of age, malignancy, or other severe diseases, 118 (41%) of these were not contacted. Of 157 recipients screened for HCV, 128 (82%) were anti-HCV positive on enzyme-linked immunosorbent assay, and 88 (56%) were HCV RNA positive. Among the HCV RNA-positive recipients, symptoms were present in 38 percent (25/66 reported), elevated alanine aminotransferase was found in 53 percent (41/77 tested), and cirrhosis was found in 11 percent (6/54 biopsied). Treatment with interferon alpha was initiated in 23 patients, corresponding to 26 percent of HCV RNA positive recipients.

CONCLUSION

Among tested recipients in the Danish HCV lookback, most were anti-HCV positive and more than half were still viremic. The morbidity was considerable, and one-fourth of viremic recipients entered treatment.

HCV-Infection in blood donors: association between anti-HCV core IgM antibodies and serum HCV RNA

Among 47 blood donors tested positive with HCV EIA 2.0 Abbott, 27 (57.4%) also reacted with four ¿third-generation' EIAs. The presence of anti-HCV antibodies was confirmed with 3 different immunoblot assays in 16 of 27 sera (34.0%) while 10 samples (21.3%) had indeterminate profile with antibodies usually directed against structural core antigen. Anti-HCV core IgM response was found in 12 of 47 sera (25.5%) and HCV viremia detected by the polymerase chain reaction (PCR) procedure was observed in 15 samples (31.9%). A comparative study of the different markers confirmed a good correlation between a strong antibody response in EIAs and immunoblot assays and the presence of HCV RNA in the serum; only 2 immunoblot indeterminate samples were PCR positive. An association was observed between IgM antibodies against "core' epitopes and HCV RNA carriage: all IgM-positive sera were found positive by PCR. However, the direct detection of viral genome remains the best method for identifying HCV carriers in the blood donor population.

Anti-HCV related to HCV PCR and risk factors analysis in a blood donor population of central Brazil

Data concerning HCV infection in Central Brazil are rare. Upon testing 2,350 voluntary blood donors from this region, we found anti-HCV prevalence rates of 2.2% by a second generation ELISA and 1.4% after confirmation by a line immunoassay. Antibodies against core, NS4, and NS5 antigens of HCV were detected in 81.8%, 72.7%, and 57.5%, respectively, of the positive samples in the line immunoassay. HCV viremia was present in 76.6% of the anti-HCV-positive blood donors. A relation was observed between PCR positivity and serum reactivity in recognizing different HCV antigens in the line immunoassay. The majority of the positive donors had history of previous parenteral exposure. While the combination of ALT > 50 IU/l and anti-HBc positivity do not appear to be good surrogate markers for HCV infection, the use of both ALT anti-HCV tests is indicated in the screening of Brazilian blood donors.