Residual risk of transfusion-transmitted viral infections in Shenzhen, China, 2001 through 2004

Trends in prevalence of hepatitis B virus infection among Iranian blood donors, 1998-2007

Assessment of the quality of donor selection and safety of the blood supply can be estimated by monitoring the prevalence of the serologic markers of infectious disease in screening tests. In the present study, changes in rates of hepatitis B virus (HBV) infection are studied in the period 1998-2007 in Iranian Blood Transfusion Organization (IBTO). Prevalence of serological marker of HBV infection [hepatitis B surface antigen (HBsAg)] was evaluated in blood donations in Iran as well as for Fars province representing a low prevalence, and Sistan-Baluchestan (S&B) province as a high prevalence region throughout 1998-2007. For assessing frequency of infection, the prevalence of HBsAg per 100 000 donations and 95% confidential intervals (95% CIs) is calculated. P value is estimated by chi(2) test. A total of 14 599 783 donations were collected during 10 years. The overall HBsAg prevalence rates declined from a 1.79% (1789/100 000 donations) in 1998 to 0.41% (409/100 000 donations) in 2007 in Iran. In Fars province, HBsAg prevalence decreased from 0.89% in 92 999 donations in 1998 to 0.34% in 148 014 donations in 2007 and in S&B province, the rate of HBsAg has gone down from 3.74% in 44 036 donations in 1998 to 1.15% in 56 057 donations in 2007. The frequency of HBV infection entering the blood supply has decreased over this period as a result of improvement in donor recruitment and selection, usage of software in transfusion services and possibly decreasing HBV infection prevalence in general population.

Two HBV DNA+/HBsAg- blood donors identified by HBV NAT in Shenzhen, China

BACKGROUND

In order to further improve blood safety, mini-pool (MP) nucleic acid testing (NAT) was implemented to screen samples negative for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV), anti-human immunodeficiency virus (anti-HIV), syphilis (anti-Treponemal antibody) and with normal ALT.

STUDY DESIGN AND METHODS

From August 2006 to February 2008, 41,301 donations were screened using commercial HIV/HCV RNA and HBV DNA Real-Time PCR NAT assays in pools of 8. Reactive pools were re-tested as individual samples using the appropriate screening test and confirmed using an alternate commercial NAT assay. Donors reactive on both NAT assays were considered 'confirmed' positive for the virus concerned and recalled for additional follow-up testing and counseling.

RESULTS

Of the 41,301 samples screened, no HIV or HCV RNA-positive/seronegative donations were detected but two HBV DNA positive/HBsAg negative blood donors (Donors 1 and 2) were identified. Their respective hepatitis immunological markers were: Donor 1 - anti-HBc positive/anti-HBe positive/HBeAg negative/ALT normal and HBV DNA viral load of 112 IU/ml; Donor 2 - anti-HBc positive/anti-HBe negative/HBeAg negative/ALT normal and HBV DNA viral load 2750 IU/ml.

CONCLUSIONS

MP NAT identified two HBsAg negative donors with presumed occult infection but no HIV or HCV seronegative/NAT positive (yield) donors. The HBV yield rate of 1 in 20,650 (95%CI - 1 in 5663 to 1 in 75,303) is comparatively high, exceeds the predicted rate based on previous modeling for the population and demonstrates the incremental blood safety value of NAT in countries where HBV is highly epidemic. The low viral load of the two yield samples underscores the importance of optimizing the sensitivity of the HBV NAT assay selected for screening.

A method for estimating incidence rate of infectious diseases among first-time blood donors

BACKGROUND

In certain circumstances, there is no method for estimating incidence based on testing results on a single blood sample from first-time blood donors, severely limiting the ability to assess the residual risk of blood-borne infections among this donor subpopulation.

STUDY DESIGN AND METHODS

Incidence rates were estimated for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) among first-time donors using the formula (P(2) - P(1))/D, where P(1) is the prevalence among blood donations from first-time donors of the minimum eligible ages for donation, P(2) is the prevalence among donations from first-time donors of an older age group, and D is the age difference (in years) between the older and younger donor groups.

RESULTS

Estimating incidence among first-time donors using the proposed method based on a single test for anti-HCV produced similar results to those based on HCV nucleic acid test (NAT) yield cases, by sex and in different periods. Comparison of the proposed method with HIV NAT yield also showed similar results although the small number of HIV NAT yield cases limits interpretation.

CONCLUSIONS

The proposed method provides an alternative way for estimating incidence of certain blood-borne infections among first-time donors, provided that our assumptions are met. It helps residual risk assessment in donor populations where first-time donors account for most of the donations and only one test result is available for each donor.

Acute hepatitis B 14 years after the implementation of universal vaccination in Italy: areas of improvement and emerging challenges

BACKGROUND

Italy had intermediate-level endemicity for hepatitis B virus (HBV) infection in the 1970s and 1980s. In 1991, vaccination of infants and adolescents became mandatory. We report the impact of universal vaccination 14 years after its beginning.

METHODS

We performed a case-control study within a population-based surveillance for acute viral hepatitis. The incidence of acute hepatitis B (AHB) was estimated for the time since 1991, and the association between AHB and the considered risk factors was analyzed for the period 2001-2005.

RESULTS

The incidence of AHB progressively decreased from 1991 to 2005, mainly for persons in the age groups targeted by the universal vaccination campaign: there was a 24-fold and 50-fold decrease in the 15-24-year and 0-14-year age groups, respectively; for the > or =25-year age group, the incidence halved. Owing to the persons' ages, approximately 3% of total AHB cases should have been the target of vaccination campaign. In 2004-2005, foreigners accounted for 14% of total cases and for 57% of persons who should have been targets for vaccination. Missed opportunities for immunization were documented for approximately 50% of patients with AHB who reported cohabitation with HBV carriers and for 70% of those who reported injection drug use. The strongest associations with AHB were found for blood transfusion (adjusted odds ratio [OR(adj)], 8.4; 95% confidence interval [CI], 2.7-26), cohabitation with HBV carriers (OR(adj), 5.3; 95% CI, 3.6-7.7), injection drug use (OR(adj), 3.8; 95% CI, 2.5-5.8), and unsafe sexual practices (OR(adj), 2.8; 95% CI, 1.9-4.2).

CONCLUSION

Universal vaccination has contributed to a decreasing AHB incidence in Italy, especially by reducing the risk of infection among persons aged 15-24 years. Most infections occur in persons aged > or =25 years in association with injection drug use, unsafe sexual activity, percutaneous treatment, and iatrogenic exposure. Improvement of vaccine coverage in high-risk groups and adherence to infection control measures during surgery and percutaneous treatment are needed. The high risk still associated with blood transfusion needs to be further investigated, with consideration of occult HBV infection in blood donors. The potential spread of HBV infection from the immigrant population deserves adequate health policy prevention programs.

Risk factors for hepatitis C virus infection among blood donors in Beijing and implications for improving the pretesting donor screening process

BACKGROUND

The objective was to determine risk factors of hepatitis C virus (HCV) infection in blood donors in Beijing.

STUDY DESIGN AND METHODS

A cross-sectional study was conducted in a total of 112 volunteer blood donors at Beijing Red Cross Blood Center (BRCBC) who were identified between January 2002 and December 2003 due to isolated HCV antibody reactivity at a donor screening procedure. The donors were recalled and interviewed about possible risk factor history. Additional blood samples were tested in repeated enzyme immunoassay, recombinant immunoblot assay, and nested reverse transcription-polymerase chain reaction. Chi-square test, analysis of variance, and multivariate logistic regression analysis were conducted to examine associations between HCV serostatus and potential risk factors.

RESULTS

Among donors identified with isolated HCV antibody reactivity at donor screening, the prevalence of confirmed HCV infection was 31.3 percent (95% confidence interval [CI], 22.0%-39.2%) and indeterminate HCV infection was 22.3 percent (95% CI, 14.7%-30.3%), and the negative prevalence was 46.4 percent (95% CI, 37.5%-56.1%). The confirmed HCV cases were more likely than the indeterminate HCV cases to have the histories of previous transfusion, plasma donation, and hepatitis infection or elevated alanine aminotransferase (ALT), whereas the HCV-negative subjects were least likely to have the above histories (p < 0.05).

CONCLUSION

Histories of blood transfusion before 1995, plasma donation, previous hepatitis infection, or elevated ALT were risk factors for HCV infection among blood donors in Beijing.

Deactivation of human immunodeficiency virus type 1 in medium by copper oxide-containing filters

Human immunodeficiency virus type 1 (HIV-1) can be transmitted through breast-feeding and through contaminated blood donations. Copper has potent biocidal properties and has been found to inactivate HIV-1 infectivity. The objective of this study was to determine the capacity of copper-based filters to inactivate HIV-1 in culture media. Medium spiked with high titers of HIV-1 was exposed to copper oxide powder or copper oxide-impregnated fibers or passed through copper-based filters, and the infectious viral titers before and after treatment were determined. Cell-free and cell-associated HIV-1 infectivity was inhibited when exposed to copper oxide in a dose-dependent manner, without cytotoxicity at the active antiviral copper concentrations. Similar dose-dependent inhibition occurred when HIV-1 was exposed to copper-impregnated fibers. Filtration of HIV-1 through filters containing the copper powder or copper-impregnated fibers resulted in viral deactivation of all 12 wild-type or drug-resistant laboratory or clinical, macrophage-tropic and T-cell-tropic, clade A, B, or C, HIV-1 isolates tested. Viral inactivation was not strain specific. Thus, a novel means to inactivate HIV-1 in medium has been developed. This inexpensive methodology may significantly reduce HIV-1 transmission from "mother to child" and/or through blood donations if proven to be effective in breast milk or plasma and safe for use. The successful application of this technology may impact HIV-1 transmission, especially in developing countries where HIV-1 is rampant.