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

Cost-benefit analysis of serological and nucleic acid testing for hepatitis B virus in blood donors in southern China

BACKGROUND

Most Chinese blood centers have implemented mini pool (MP) HBV nucleic acid testing (NAT) together with HBsAg ELISA in routine blood donor screening for HBV infection since 2015, and a few centers upgraded MP to individual donation (ID) NAT screening recently, raising urgent need for cost-benefit analysis of different screening strategies. In an effort to prevent transfusion-transmitted infections (TTIs) for HBV, cost-benefit analyses of three different screening strategies: HBsAg alone, HBsAg plus MP NAT and HBsAg plus ID NAT were performed in blood donors from southern China where HBV infection was endemic.

METHODS

MP-6 HBV NAT and ID NAT were adopted in parallel to screen blood donors for further comparative analysis. On the basis of screening data and the documented parameters, the number of window period (WP) infection, HBV acute infection, chronic hepatitis B infection (CHB) and occult hepatitis B infection (OBI) was evaluated, and the potential prevented HBV TTIs and benefits of these three strategies were predicted based on cost-benefit analysis by an estimation model.

RESULTS

Of 132,323 donations, the yield rate for HBsAg-/DNA + screened by ID NAT (0.12%) was significantly higher than that by MP NAT (0.058%, P < 0.05). Furthermore, the predicted transfusion-transmitted HBV cases prevented was 1.25 times more by ID NAT compared to MP-6 NAT. The cost-benefit ratio of the universal HBsAg screening, HBsAg plus ID NAT and HBsAg plus MP NAT were 1:58, 1:27 and 1:22, respectively.

CONCLUSIONS

Universal HBsAg ELISA screening in combination with HBV ID NAT or MP-6 NAT strategies was highly cost effective in China. To further improve blood safety, HBsAg plus HBV DNA ID NAT screening should be considered in HBV endemic regions/countries.

Comparative analysis of hepatitis B virus infections in blood donors born before and after the implementation of universal HBV vaccination in southern China

BACKGROUND

In China, the vaccinated blood donors have rapidly increased by recent years, which may impact blood safety. The true prevalence of HBV between vaccinated blood donors and non-vaccinated blood donors should be explored.

STUDY DESIGN AND METHODS

The samples of blood donors were collected and detected for serologic markers of HBV in the Shenzhen Blood Centre (SZBC). The discrepant results were tested with commercial electrochemiluminescence immunoassay (ELCI) for HBsAg, anti-HBs, HBeAg, Anti-HBe and Anti-HBc, alternative MPX ID NAT, nested PCR, and a quantitative real-time polymerase chain reaction (qPCR) assay for HBV DNA. The serological and molecular characteristics of HBV infected blood donors were analysed, and the effects on blood safety for donors born before and after the implementation of universal HBV vaccination were compared.

RESULTS

Out of 242 presumed HBV infected donors from 26 318 donations, 131 (0.49%, [95% CI, 0.43-0.59]) chronic HBV infections (CHB, HBsAg detected with or without DNA), 58 (0.22%, [95% CI, 0.17-0.28]) occult hepatitis B infections (OBI, HBsAg not detected, assume anti-HBc positive and/or anti-HBs with HBV DNA) and 3 (0.011%, [95% CI, 0.0023-0.033]) window period (WP) infections were confirmed respectively. There were 28 CHBs (0.44%), 7 OBIs (0.11%) and 1 WP (0.016%) from vaccinated blood donor and 103 CHBs (0.52%), 51 OBIs (0.26%) and 2 WPs (0.01%) from non-vaccinated blood donor. The HBV+ (CHBs, OBIs and WPs) rate (0.56%) in vaccinated donors was lower than in non-vaccinated donors (0.78%, p < 0.05). The HBsAg titers of vaccinated infected blood donors (Median: 128.8 IU/ml) were much higher than non-vaccinated infected blood donors (58.4 IU/ml). The OBI yield rates in the vaccinated blood donors was significantly lower than the non-vaccinated blood donors (p < 0.05). There 102/124 (82.3%) samples were genotype B, 22/124 (17.7%) were genotype C respectively. There was no significant difference in the distribution of genotype between non-vaccinated blood donors (B/C, 86/17) and vaccinated blood donors (B/C, 23/6; p > 0.05). High frequency of vaccine escape mutations M133L (32.4%) and E164G in S region of genotype B strains and substitution L175S (40.9%) related to vaccine escape in S region of genotype C strains were identified.

CONCLUSION

The universal HBV vaccination program markedly reduces the risk of HBV infection in blood donors, and provides a significant guarantee for the safety of blood transfusion. Several important mutations detected related vaccine escape and notable mutations needed further investigated.

Occurrence of occult hepatitis B virus infection associated with envelope protein mutations according to anti-HBs carriage in blood donors

OBJECTIVES

Occult hepatitis B virus infection (OBI) carries a risk of hepatitis B virus (HBV) transmission and hepatocellular carcinoma. As previous studies have had a limited sample size, the characteristics of OBI with genotype B and C (OBI_B and OBI_C) mutations relating to hepatitis B surface antibody (anti-HBs) elicited by vaccination or a limited host immune response to HBV have not been fully explored.

METHODS

In this study, the occurrence of OBI_B or OBI_C strains associated with envelope protein (pre-S/S) amino acid substitutions obtained from 99 blood donors stratified according to anti-HBs carriage were characterized extensively.

RESULTS

According to the presence of anti-HBs within each genotype, the number and frequency of substitution sites specific for anti-HBs(-) OBI_B were higher than those specific for anti-HBs(+) OBI_B strains (67 vs 31; 117 vs 41), but the reverse pattern was found in OBI_C strains (3 vs 24; 3 vs 26). Mutations pre-s₁T68I and sQ129R/L were found uniquely in 15-25% of anti-HBs(+) OBI_B carriers and mutation pre-s₁A54E was found preferentially in anti-HBs(+) OBI_C, while 17 substitutions were found preferentially in 11-38% of anti-HBs(-) OBI_B strains. In the major hydrophilic region (MHR) region, mutations sS167 in OBI_B, sT118 in OBI_C, and sA166 in both genotypes were possibly immune-induced escape mutation sites.

CONCLUSIONS

Several mutations in pre-S/S of OBI appeared to be associated with carrier anti-HBs pressure, which might be risk factors for potential reactivation of viruses under anti-HBs selection in OBI carriers.

Prevalence of Anti-HCV Antibody Among the General Population in Mainland China Between 1991 and 2015: A Systematic Review and Meta-analysis

Our study aims to estimate the burden of hepatitis C virus (HCV) infection among the general population in Mainland China. We searched 4 databases for studies of the prevalence of anti-HCV antibody among the general population. Studies that met the selection criteria were included in the meta-analysis. Ninety-four studies with 10729 929 individuals were finally included. Overall, the prevalence of anti-HCV antibody among the general population in Mainland China is 0.91% (95% confidence interval, 0.81%-1.03%). The prevalence rates of anti-HCV antibody were geographically different, with a range of 0.32%-6.51%, and the East and South of China had a relatively lower prevalence. The prevalence of anti-HCV antibody increased successively from 0.16% to 3.95% with advancing age. It was noteworthy that the prevalence of anti-HCV antibody decreased continuously from 2.09% to 0.45% during 1991-2010, whereas it increased to 0.58% during 2011-2015.

Estimation of hepatitis B-positive rates in Chinese blood donors by combining predonation and postdonation screening results

BACKGROUND

Chinese blood centers use Hepatitis B surface antigen (HBsAg) rapid test (RT) in pre-donation and two rounds of screening with different enzyme-linked immunosorbent assays in post-donation. Nucleic acid testing (NAT) on screening non-reactive (SC-) donations has been gradually implemented since 2010. Yet RT+ and SC-/NAT+ donors are seldom included in hepatitis B virus (HBV) positive rate estimates in Chinese blood donors.

METHODS

We performed HBsAg neutralization test (NT) on whole blood (WB) with pre-donation RT+ results and post-donation screening reactive (SC+) samples from Mianyang and Chongqing in 2015. The annual totals of pre- and post-donation NT+ donors were combined with the annual totals of SC-/NAT+ donors to derive the estimated HBV positive rates.

RESULT

In Mianyang and Chongqing, 59.4% and 68.2% of RT+ donors in Jan-Aug 2015 contributed for NT, 95.5% and 97.2% of which were NT+ respectively. In 2015, 422 and 667 donors from Mianyang and Chongqing respectively were HBsAg RT+, yielding estimated 403 and 648 pre-donation RT+/NT+ deferrals. 411 and 668 post-donation SC+ samples were NT tested from Mianyang and Chongqing, of which 249 and 323 were NT+ respectively. An estimated 63 donors in Mianyang and 88 donors in Chongqing were SC-/NAT+. The estimated HBV confirmed positive rate in blood donors are 1.59% in Mianyang and 1.01% in Chongqing.

CONCLUSION

Pre-donation HBsAg RT effectively intercepts donations from HBV infected donors. Using NT confirmatory results from RT+, SC+ and SC-/NAT+ donors, this study provides a model for more accurate estimation for HBV positive rates in China.

Effectiveness of a flow-based device using riboflavin photochemistry in damaging blood-borne viral nucleic acids

BACKGROUND

Effectiveness of a flow-based treatment device using riboflavin photochemistry was demonstrated by cytopathic effect method using indicator viruses. However, inactivation efficacy against real blood-borne viruses needs to be evaluated, especially at nucleic acid level.

MATERIAL AND METHODS

Special plasma samples with varying concentrations of blood-borne virus were selected using a strict blood selection procedure and were treated with device treatment (DT). Nucleic acid test (NAT) using polymerase chain reaction fluorescence method was used to detect virus copies.

RESULTS

The NAT value of 4325 in plasma with high Hepatitis B Virus (HBV) concentrations decreased to 1330 with DT. After 100-fold dilution, the NAT value was below the NAT detection limits with DT compared with 23.0 that without DT. The NAT value of 61.9 in plasma with medium HBV concentrations decreased to 37.8 with DT, and after 10-fold dilution, the NAT value was below the NAT detection limits with DT compared with below 20 that without DT. The Ct values of plasma with low concentrations of blood-borne viruses were below the NAT detection limits with DT.

CONCLUSION

There was a dose effect with DT which was effective in blood-borne viruses damaging nucleic acids to a level below the NAT detection limits.

Hepatitis B Virus Blood Screening: Need for Reappraisal of Blood Safety Measures?

Over the past decades, the risk of HBV transfusion–transmission has been steadily reduced through the recruitment of volunteer donors, the selection of donors based on risk-behavior evaluation, the development of increasingly more sensitive hepatitis B antigen (HBsAg) assays, the use of hepatitis B core antibody (anti-HBc) screening in some low-endemic countries, and the recent implementation of HBV nucleic acid testing (NAT). Despite this accumulation of blood safety measures, the desirable zero risk goal has yet to be achieved. The residual risk of HBV transfusion–transmission appears associated with the preseroconversion window period and occult HBV infection characterized by the absence of detectable HBsAg and extremely low levels of HBV DNA. Infected donations tested false-negative with serology and/or NAT still persist and derived blood components were shown to transmit the virus, although rarely. Questions regarding the apparent redundancy of some safety measures prompted debates on how to reduce the cost of HBV blood screening. In particular, accumulating data strongly suggests that HBsAg testing may add little, if any HBV risk reduction value when HBV NAT and anti-HBc screening also apply. Absence or minimal acceptable infectious risk needs to be assessed before considering discontinuing HBsAg. Nevertheless, HBsAg remains essential in high-endemic settings where anti-HBc testing cannot be implemented without compromising blood availability. HBV screening strategy should be decided according to local epidemiology, estimate of the infectious risk, and resources.

Epidemiology of hepatitis B virus infection: results from a community-based study of 0.15 million residents in South China

Limited information is available about the current epidemic status of hepatitis B virus (HBV) in Guangdong province in South China, where hepatitis B is endemic. We sought to provide an up-to-date assessment of hepatitis B prevalence in a large population through a community-based study. A total of 169,211 local residents were recruited using the stratified cluster random sampling method from 2014 to 2015, and each participant's information was collected using an interviewer-administered questionnaire. Accordingly, the prevalence of hepatitis B surface antigen (HBsAg) in the total population was 8.76%. HBsAg prevalence was lowest (0.29%) among children aged 0-12 years and highest (12.71%) among those aged 23-59 years. Moreover, the prevalence (8.82%) in males approximately equalled that (8.65%) in females (P > 0.05). Overall, vaccination was effective in preventing HBV infection, regardless of age. Among adults aged 23-59 years, male sex tended to keep the HBsAg persistence. However, reduced persistence for participants with occasional physical exercise and drinking was observed. For participants older than 59 years, a history of prior surgery placed people at high risk for infection. Although Guangdong has successfully decreased the HBsAg prevalence among children, it is urgent to expand vaccination to adults, and employ interventions to reduce the infection risk.

Prevalence of hepatitis B surface antigen (HBsAg) in a blood donor population born prior to and after implementation of universal HBV vaccination in Shenzhen, China

Background

Neonatal hepatitis B vaccination program at birth has been implemented nationwide since 1992 in China. However, current HBV prevalence status in blood donors has not been entirely examined, which may impact HBV safety in blood donations as the vaccinees over 18 years old progressively become the majority population of blood donors.

Methods

In this study, 569,145 blood donors were screened for HBsAg by rapid tests and enzyme immunoassays, among them 475,538 blood samples with negative HBsAg were further screened for HBV DNA by nucleic acid testing between 2005 and 2014 at Shenzhen blood center.

Results

An overall 2.3 % HBsAg prevalence was found in the blood donor population during the past 10 years (2.86 % in 2005, 1.76 % in 2010, and 2.79 % in 2014, respectively). HBsAg seroconversion occurred in 0.37 % of repeat-donors. When stratified by age, the prevalence of HBsAg was found significantly higher in younger donors age 18–25 years (2.73 %) than in those 26–35 years (2.13 %), 36–45 years (2.03 %) and 46–58 years (1.71 %) (P < 0.001), unexpectedly suggesting that younger donors remained at risk of chronic HBV infection. Assuming that donors aged 18–22 born before or after 1992 were non-vaccinated and vaccinated, respectively, HBsAg prevalence was higher in first-time donors born ≥1992 (3.9 %) than prior to 1992 (3.5 %, P = 0.005). The incidence of HBV infection in the 5-year period examined was significantly lower in repeat-donors born ≥1992 (0.27 %) than prior to 1992 (0.6 %, P = 0.008). The yield of HBV DNA+/HBsAg- donors was 1:3,302, including 1:4,486 occult infections and 1:43,231 window period infections.

Conclusion

Young blood donors born after implementation of universal HBV vaccination in China presented higher prevalence of HBsAg but lower incidence of HBsAg seroconversion than older, presumed unvaccinated, donors. HBV vaccine boosting for adolescents at 15–17 years old prior to reaching blood donor age might help improve blood safety.

Acceptability of Voluntary Medical Male Circumcision (VMMC) among Male Sexually Transmitted Diseases Patients (MSTDP) in China

Voluntary Medical Male circumcision (VMMC) is an evidence-based, yet under-utilized biomedical HIV intervention in China. No study has investigated acceptability of VMMC among male sexually transmitted diseases patients (MSTDP) who are at high risk of HIV transmission. A cross-sectional survey interviewed 350 HIV negative heterosexual MSTDP in Shenzhen, China; 12.0% (n = 42) of them were circumcised at the time of survey. When the uncircumcised participants (n = 308) were informed that VMMC could reduce the risk of HIV infection via heterosexual intercourse by 50%, the prevalence of acceptability of VMMC in the next six months was 46.1%. Adjusted for significant background variables, significant factors of acceptability of VMMC included: 1) emotional variables: the Emotional Representation Subscale (adjusted odds ratios, AOR = 1.13, 95%CI: 1.06–1.18), 2) cognitive variables derived from Health Belief Model (HBM): perceived some chance of having sex with HIV positive women in the next 12 months (AOR = 2.48, 95%CI: 1.15–5.33) (perceived susceptibility), perceived severity of STD infection (AOR = 1.06, 95%CI: 1.02–1.10), perceived benefit of VMMC in risk reduction (AOR = 1.29, 95%CI: 1.16–1.42) and sexual performance (AOR = 1.45, 95%CI: 1.26–1.71), perceived barriers against taking up VMMC (AOR = 0.88, 95%CI: 0.81–0.95), and perceived cue to action (AOR = 1.41, 95%CI: 1.23–1.61) and self-efficacy (AOR = 1.38, 95%CI: 1.26–1.35) related to taking up VMMC. The association between perceived severity of STD infection and acceptability was fully mediated by emotional representation of STD infection. The relatively low prevalence of circumcision and high acceptability suggested that the situation was favorable for implementing VMMC as a means of HIV intervention among MSTDP in China. HBM is a potential suitable framework to guide the design of future VMMC promotion. Future implementation programs should be conducted in STD clinic settings, taking the important findings of this study into account.

Impact of using different blood donor subpopulations and models on the estimation of transfusion transmission residual risk of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus in Zimbabwe

BACKGROUND

Various models for estimating the residual risk (RR) of transmission of infections by blood transfusion have been published mainly based on data from high-income countries. However, to obtain the data required for such an assessment remains challenging for most developing settings. The National Blood Service Zimbabwe (NBSZ) adapted a published incidence-window period (IWP) model, which has less demanding data requirements. In this study we assess the impact of various definitions of blood donor subpopulations and models on RR estimates. We compared the outcomes of two published models and an adapted NBSZ model.

STUDY DESIGN AND METHODS

The Schreiber IWP model (Model 1), an amended version (Model 2), and an adapted NBSZ model (Model 3) were applied. Variably the three models include prevalence, incidence, preseroconversion intervals, mean lifetime risk, and person-years at risk. Annual mean RR estimates and 95% confidence intervals for each of the three models for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were determined using NBSZ blood donor data from 2002 through 2011.

RESULTS

The annual mean RR estimates for Models 1 through 3 were 1 in 6542, 5805, and 6418, respectively for HIV; 1 in 1978, 2027, and 1628 for HBV; and 1 in 9588, 15,126, and 7750, for HCV.

CONCLUSIONS

The adapted NBSZ model provided comparable results to the published methods and these highlight the high occurrence of HBV in Zimbabwe. The adapted NBSZ model could be used as an alternative to estimate RRs when in settings where two repeat donations are not available.

The estimation of prevalence and risk factors of hepatitis B virus infection among blood donors in Chengdu, China

The reported positive rates of hepatitis B virus surface antigen (HBsAg) among Chinese blood donors generally do not include data from pre-donation rapid tests. The aim of this study was to estimate the prevalence of serologic markers for HBsAg and risk factors among blood donors from Chengdu, China. From April 2010 to March 2011, a total of 16,875 blood donors were enrolled. Data from HBsAg tests before and after donations were collected to estimate the prevalence of HBsAg. A case-control study was conducted in 265 unique HBsAg-positive blood donors and 530 seronegative donors between January 2011 and October 2012. The odds ratio (OR) and 95% confidence interval (CI) were calculated using conditional logistic regression. The population attributable risk (PAR) was estimated. The prevalence of HBsAg was 3.17% (95%CI, 2.91-3.43%). The following risk factors were associated with HBV infection: non-vaccination for HBV (OR = 4.236; 95%CI, 2.72-6.60%), razor sharing (OR = 2.370; 95%CI, 1.46-3.84%), dental treatment (OR = 1.714; 95%CI, 1.21-2.43%), acupuncture (OR = 1.983; 95%CI, 1.20-3.28%), a family history of HBV infection (OR = 2.257; 95%CI, 1.32-3.86%), and endoscopy (OR = 2.17; 95%CI, 1.04-4.51%). The PAR values of the risk factors were 42.77%, 31.78%, 13.68%, 6.18%, 6.09%, and 2.85%, respectively, and the total PAR was 68.78%. The prevalence of HBsAg among Chinese blood donors is still high. HBV vaccinations can provide protection. Blood contact from sharing instruments is still a high risk route of transmission for HBV. Immunization programs and behavioral interventions should be used to prevent blood donation infections and improve blood safety.

Prevalence and trends of transfusion-transmitted infections among blood donors in Tehran, Iran from 2008 to 2013

BACKGROUND

Evaluation of trends in the rate of transfusion-transmitted infections (TTIs) in blood donors is essential for monitoring blood supply safety and donor screening effectiveness. The aim of this study was to determine the trends and prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis seromarkers among blood donors referred to Tehran Blood Transfusion Center (TBTC) from 2008 to 2013.

MATERIALS AND METHODS

The data of all blood donors referred to TBTC between 2008 and 2013 were collected. The prevalence of HBV, HCV, HIV, and syphilis infections were expressed by donation year and donors' characteristics (age, gender, educational level and donor status).

RESULTS

Among 1,796,090 individuals who donated blood at TBTC from 2008 to 2013, analysis of trend for the prevalence of HBV showed a significant decrease from 423 to 153 per 10(5) donors. The similar pattern of decrease was observed for the prevalence of HCV from 139 to 69 per 10(5) donors, however the rate of decrease in HCV prevalence was slower than the rate of decrease in HBV prevalence. The prevalence of HIV was constant while the prevalence of syphilis showed a sharp decrease in 2009 and a constant prevalence from 2010 to 2013. The top three parameters influenced the rate of TTIs were donor status, age, and educational level.

CONCLUSION

The decreasing prevalence and trends of TTIs among the studied donors demonstrated that the safety measures which were employed in recent years in Iranian Blood Transfusion Organization have been effective.

Risk factors for hepatitis B and C infection among blood donors in five Chinese blood centers

BACKGROUND

Few studies were conducted on hepatitis B and C virus (HBV and HCV, respectively) risk factors among Chinese blood donors in recent years since voluntary donors replaced commercial donors.

STUDY DESIGN AND METHODS

A case-control survey was conducted in HBV- or HCV-positive and -negative donors from five blood centers in China between September 2009 and April 2011. Case status was defined by having a reactive result on Monolisa HBsAg Ultra (Bio-Rad) for HBV and Ortho anti-HCV EIA 3.0 (Johnson & Johnson) for HCV. Controls were randomly selected qualified blood donors matched to cases by donation month and blood center. Specific test-seeking, medical-related, and behavioral risk factors were compared by HBV and HCV status using chi-square tests or Fisher's exact tests with Bonferroni correction.

RESULTS

A total of 364 HBV cases, 174 HCV cases, and 689 controls completed the survey; response rates were 66.2, 47.3, and 82%, respectively. HCV-positive donors were significantly more likely to report having a blood transfusion history (23.4% vs. 3.0%, p < 0.0001) and ever living with a person with illegal drug injection (6.0% vs. 0.5%, p < 0.0001) than controls. Having intravenous and intramuscular injections in the past 12 months and ever having a tattoo are marginal risk factors for HCV (p values < 0.01). No specific risk factor for HBV was identified.

CONCLUSION

History of previous transfusion and living with illegal drug users are risk factors for HCV infection among Chinese blood donors from five regions. Test-seeking behavior is not associated with HBV or HCV infections.

A population-based study examining hepatitis B virus infection and immunization rates in Northwest China

Background and Aim

Current baseline data regarding the prevalence of hepatitis B virus (HBV) infections and the immune status in hyperendemic areas is necessary in evaluating the effectiveness of ongoing HBV prevention and control programs in northwest China. This study aims to determine the prevalence of chronic HBV infections, past exposure rates, and immune response profiles in Wuwei City, northwest China in 2010.

Methods

Cross-sectional household survey representative of the Wuwei City population. 28,579 participants were interviewed in the seroepidemiological survey ≥1 year of age. House to house screening was conducted using a standard questionnaire. All serum samples were screened by enzyme-linked immunoassays for the presence of hepatitis B surface antigen, antibodies against HBV surface antigen, and antibodies to the hepatitis B core antigen.

Results

Among individuals ≥1 year of age, 7.2% (95%CI: 6.3–8.1%) had chronic HBV infections, 43.9% (CI: 40.4–47.4%) had been exposed to HBV, and 23.49% (CI: 21.6–25.3%) had vaccine-induced immunity. Multi-factor weighted logistic regression analysis showed that having household contact with HBV carriers (OR = 2.6, 95%CI: 2.3–3.0) and beauty treatments in public places (OR = 1.2, 95%CI: 1.1–1.3) were the risk factors of HBV infection in whole population. Having household contact with HBV carriers (OR = 3.8, 95% CI: 2.2–6.5) and lack of hepatitis vaccination (OR = 2.0, 95% CI: 1.4–3.3) were the risk factors for HBV infection in children aged 1–14 years.

Conclusions

Hepatitis B infection remains a serious public health problem in northwest China. Having household contact with HBV carriers and beauty treatments in public places represented HBV infection risk factors. Hepatitis B vaccine immunization strategies need further improvement, particularly by targeting the immunization of rural migrant workers.

Prevalence and trend of major transfusion-transmissible infections among blood donors in Western China, 2005 through 2010

BACKGROUND

The prevalence of transfusion-transmissible infections (TTIs) in blood donations is important for evaluating blood safety and potential risks to the population. This study investigated the prevalence of TTIs among blood donors in Western China and suggested measures for policy-makers.

METHODS

The screening results of 66,311 donations between 2005 and 2010 from a central blood center in Western China were analyzed. The prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis infections were expressed in percentages for the entire study group as well as groups by demographic characteristics and donation frequency, with differences analyzed using Fisher's exact or Chi-square test. Logistic regression was performed to identify the influencing factors of the detected results.

RESULTS

1,769 (2.67%, 95% CI 2.55-2.79%) of the donated blood had serological evidence of infection with at least one pathogen and 44 (0.07%, 95% CI 0.05-0.09%) showed evidence of multiple infections. The seroprevalence of HBV, HCV, HIV, and syphilis infections was 0.87% (95% CI 0.80-0.94%), 0.86% (95% CI 0.79-0.93%), 0.31% (95% CI 0.26-0.35%), and 0.70% (95% CI 0.64-0.76%) respectively. Trend analysis for the prevalence of TTIs showed a significant increase from 2.44% to 3.71% (χ2 = 100.72, p = 0.00) over this 6-year period. The positive rates for TTIs varied along demographic lines. The top three risk factors in test-positive donors were identified as age, education level and donation frequency. The older age group and lower educated group were linked to a higher prevalence of TTIs. A decreasing prevalence was associated with an increasing frequency of blood donations (χ2 = 562.78, p = 0.00).

CONCLUSIONS

Hepatitis B and C were found most, and often in conjunction with syphilis. These were the primary threats to blood safety. The high positivity rate and the increasing prevalence of TTIs among blood donors in Western China call for further actions.

Current testing strategies for hepatitis C virus infection in blood donors and the way forward

Screening tests for blood donations are based upon sensitivity, cost-effectiveness and their suitability for high-throughput testing. Enzyme immunoassay (EIAs) for hepatitis C virus (HCV) antibodies were the initial screening tests introduced. The ”first generation“ antibody EIAs detected seroconversion after unduly long infectious window period. Improved HCV antibody assays still had an infectious window period around 66 d. HCV core antigen EIAs shortened the window period considerably, but high costs did not lead to widespread acceptance. A fourth-generation HCV antigen and antibody assay (combination EIA) is more convenient as two infectious markers of HCV are detected in the same assay. Molecular testing for HCV-RNA utilizing nucleic acid amplification technology (NAT) is the most sensitive assay and shortens the window period to only 4 d. Implementation of NAT in many developed countries around the world has resulted in dramatic reductions in transfusion transmissible HCV and relative risk is now < 1 per million donations. However, HCV serology still continues to be retained as some donations are serology positive but NAT negative. In resource constrained countries HCV screening is highly variable, depending upon infrastructure, trained manpower and financial resource. Rapid tests which do not require instrumentation and are simple to perform are used in many small and remotely located blood centres. The sensitivity as compared to EIAs is less and wherever feasible HCV antibody EIAs are most frequently used screening assays. Efforts have been made to implement combined antigen-antibody assays and even NAT in some of these countries.

Epidemiology of Hepatitis B Virus Infection in China: Current Status and Challenges

The prevalence of hepatitis B is high in China. Based on the National Disease Supervision Information Management System of China, the mean reported incidence of hepatitis B was 84.3 per 100,000 in China between 2005 and 2010. There are differences in population distribution based on region and ethnic group. Here, risk factors, virological characteristics, and prophylaxis of hepatitis B in China are reviewed. Although the prevalence of HBV infection is gradually declining, there are many challenges in HBV infection control, including higher prevalence in floating population, poor compliance of antiviral therapy, and high disease burden.

A pilot study on screening blood donors with individual-donation nucleic acid testing in China

BACKGROUND

Nucleic acid amplification testing (NAT) is not yet obligatory in China for blood donor screening and the risk of enzyme immunoassay (EIA)-negative, NAT-reactive donations in Chinese blood donors has rarely been reported. The aim of this study was to screen a population of Chinese blood donors using a triplex individual-donation (ID)-NAT assay and assess the safety benefits of implementing NAT.

MATERIALS AND METHODS

Between 1st August, 2010 and 31st December, 2011 all donations at a Chinese blood centre were screened individually using the Procleix® Ultrio® assay, a multiplex NAT assay for the detection of hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA and human immunodeficiency virus-1 (HIV-1) RNA. All donations were also screened for HBsAg, anti-HIV and anti-HCV using two different EIA for each marker. Samples with discordant results between NAT and EIA were further tested with an alternative NAT assay (Cobas® TaqMan®). Potential yield cases (serologically negative/NAT-reactive donors) were further evaluated when possible.

RESULTS

During the study period a total of 178,447 donations were screened by NAT and EIA, among which 169 HBV NAT yield cases (0.095%) were detected. No N AT yield cases were found for HIV-1 or HCV. For the HBV NAT yield cases, follow-up results showed that 11 (6.51%) were probable or confirmed HBV window period infections, 5 (2.96%) were chronic HBV carriers and 153 (90.53%) were probable or confirmed occult HBV infections. There was a statistically significant difference between the NAT-positive rates for first-time vs repeat donations (0.472% vs 0.146%, respectively; P<0.001).

DISCUSSION

Our data demonstrate that the potential HBV yield rate was 1:1,056 for blood donations in the Zhejiang province of China. Implementation of NAT will provide a significant increment in safety relative to serological screening alone.

Decreased antigenicity profiles of immune-escaped and drug-resistant hepatitis B surface antigen (HBsAg) double mutants

BACKGROUND

Selective pressure from either the immune response or the use of nucleoside analogs in antiviral therapy could be driving the emergence of HBV mutants. Because of the overlap of the open reading frame (ORF) S for the HBsAg and ORF P for viral polymerase, rtM204I and rtM204V mutations in the polymerase would produce sI195M and sW196S in the HBsAg. The combined effects of immune-escaped mutations (sT118M, sG145K, sG145R) and drug-resistant mutations (rtM204I, rtM204V) on the antigenicity profiles of HBsAg has not been widely explored.

METHODS

To determine the combined effects of immune-escaped and drug-resistant mutants on the antigenicity profiles of HBsAg, recombinant plasmids encoding HBsAg double mutants were constructed using site-directed mutagenesis. The supernatant from each plasmid transfection was analyzed for HBsAg in the western-blotting and five of the most commonly used commercial ELISA kits in China.

RESULTS

Western-blotting assay showed the successful expression of each HBsAg mutant. All five ELISA kits manifested similar avidity, which were demonstrated by the slope of the curves, for the sT118M mutant, and sT118M-rtM204I (sT118M-sI195M) and sT118M-rtM204V (sT118M-sW196S) double mutants, suggesting that drug-resistant YMDD mutants caused negligible losses in the antigenicity of immune-escaped sT118M HBsAg. In contrast, the presence of the rtM204I (sI195M) mutation, but not rtM204V (sW196S) in combination with the sG145K mutation significantly reduced the avidity of sG145K HBsAg. The rtM204I (sI195M) mutation also decreased the antigenicity profiles for sG145R HBsAg.

CONCLUSIONS

Drug-resistant mutations rtM204I (sI195M) and rtM204V (sW196S) caused significant reduction in antigenicity for the immune-escaped HBsAg mutants sG145K and sG145R, which may hamper HBV diagnosis and disease control from HBV blood-transfusion transmissions in China. The development of ELISA kits with a greater sensitivity for drug-resistant and immune-escaped HBsAg warrants further consideration.

The estimation of prevalence, incidence, and residual risk of transfusion-transmitted human hepatitis B infection from blood donated at the Anhui blood center, China, from 2009 to 2011

Background

The high prevalence of hepatitis B virus (HBV) among the Chinese population poses a threat to blood safety; however, few studies have examined epidemiological data regarding HBV infection of Chinese blood donors. The present study investigated the demographic characteristics of blood donors at the Anhui blood center in China, the prevalence, incidence, and residual risk (RR) associated with hepatitis B surface antigen (HBsAg) expression in terms of transfusion transmitted HBV (TTHBV) infections.

Methods

The demographic characteristics and HBV status of people who donated blood at the Anhui blood center between 2009 and 2011 were retrospectively analyzed. The incidence of HBV was estimated through HBsAg yield approach. The window period model was then used to estimate the RR of TTHBV infection.

Results

The typical donor at the Anhui blood center was a first-time volunteer, aged less than 25 years, unmarried, of Han ethnicity, and with an education below high school level. The prevalence of HBV infection among repeat donors, first-time donors, and all donors was 28.9, 127.2 and 82.1 per 100,000, respectively. The incidence estimate was 333.9 per 10⁵ person-years. Using an infectious window period of 59 days, the RR for HBV was estimated to be 1 in 1853 between 2009 and 2011.

Conclusions

The incidence and RR of HBV in Chinese blood donors are much higher than those of donors in developed countries. This is because sensitive ELISAs and nucleic acid tests are not available in China. Further work is needed to improve both the safety and availability of blood products in China.

Seroprevalence of human immunodeficiency virus in north Indian blood donors using third and fourth generation Enzyme linked immunosorbent assay

Background:

The percentage of HIV cases attributable to blood transfusion has decreased significantly in the last decade. The newer 4^th generation Enzyme linked immunosorbent assay (ELISA) has been shown to have increased sensitivity compared to 3^rd generation ELISA.

Objectives:

To estimate the seroprevalence of HIV among blood donors using 4^th generation ELISA assay and to compare it with the 3^rd generation ELISA.

Materials and Methods:

This prospective study involved 10,200 blood donors- 6,800 were voluntary donors (3400-students and 3400-non students) and 3400 were replacement donors. All blood units were tested with 3^rd as well as 4^th generation ELISA. All samples found reactive or in grey zone with either 3^rd or 4^th generation ELISA were retested by Western blot (WB).

Results:

The seroprevalence of HIV was estimated to be 1.37/1000 donations (0.14%) with 3^rd generation ELISA compared to 3.62/1000 donations (0.36%) with 4^th generation ELISA (p>0.05). The seroprevalence of HIV among voluntary donors was estimated to be 1.32/1000 donations (0.13%) with 3^rd generation ELISA and 3.67/1000 donations (0.36%) with 4^th generation ELISA. The prevalence of HIV among replacement donors was 1.47/1000 donations (0.15%) with 3^rd generation ELISA and 3.52/1000 donations (0.35%) with 4^th generation ELISA.

Conclusion:

4^th generation HIV ELISA detects a higher number of seroreactive donors compared to 3^rd generation ELISA. However, larger studies are required with confirmatory tests for both 3^rd and 4^th generation ELISA for making any policy changes.

How often are major blood-borne pathogens found in eye patients? A serosurvey at an eye hospital in Southern China

BACKGROUND

The hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) and treponema pallidum (TP) are blood-borne pathogens. They can lead to nosocomial and occupational infections in health care settings. We aimed to identify the prevalence of and risk factors associated with HBV, HCV, HIV and TP infections among patients with eye diseases at a tertiary eye hospital in Southern China.

METHODS

From July 2011 to June 2012, a total of 26,386 blood units were collected from eye patients, including inpatients and the day surgery patients at Zhongshan Ophthalmic Center, one of the biggest eye hospitals in China. Based on the primary diagnoses from this period, the subjects were classified into different ocular disease groups. All blood samples were tested for HBsAg, anti-HCV, anti-HIV and anti-TP.

RESULT

The overall prevalence of HBV, HCV, TP and HIV was 9.79%, 0.99%, 2.43% and 0.11%, respectively. The prevalence of HBsAg was much lower among patients younger than 20 years compared to other age groups. In addition, the risk of HBsAg was associated with the male gender, ocular trauma and glaucoma. The prevalence of TP increased with age and the prevalence among patients older than 30 was higher than that in patients younger than 20 years.

CONCLUSIONS

The prevalence of HBV, HCV, HIV and TP in patients with eye diseases was identified. This information can be utilised to strengthen the health education and implementation of universal safety precautions to prevent the spread of blood-borne pathogens in health care settings.

Six-year pilot study on nucleic acid testing for blood donations in China

A six-year pilot study on nucleic acid testing for HBV, HCV and HIV-1 has been undertaken on sero-negative plasmas in mini-pool and individual donation testing at Shenzhen Blood Center. Of 307,740 sero-negative blood samples, 95 of 102 HBV DNA yields were confirmed positive, 80/95 (84.2%) were classified as occult HBV infection (OBI) and 15 (15.8%) as window period cases. Amongst OBIs, 45% carried anti-HBc only, 41.3% anti-HBc and anti-HBs and 13.7% anti-HBs only. HBV DNA yield was 1:3239. One HCV WP and one HIV-1 infected donations were detected. High residual risk was found in current blood donations screening in China.

Infection status outcome, machine learning method and virus type interact to affect the optimised prediction of hepatitis virus immunoassay results from routine pathology laboratory assays in unbalanced data

Background

Advanced data mining techniques such as decision trees have been successfully used to predict a variety of outcomes in complex medical environments. Furthermore, previous research has shown that combining the results of a set of individually trained trees into an ensemble-based classifier can improve overall classification accuracy. This paper investigates the effect of data pre-processing, the use of ensembles constructed by bagging, and a simple majority vote to combine classification predictions from routine pathology laboratory data, particularly to overcome a large imbalance of negative Hepatitis B virus (HBV) and Hepatitis C virus (HCV) cases versus HBV or HCV immunoassay positive cases. These methods were illustrated using a never before analysed data set from ACT Pathology (Canberra, Australia) relating to HBV and HCV patients.

Results

It was easier to predict immunoassay positive cases than negative cases of HBV or HCV. While applying an ensemble-based approach rather than a single classifier had a small positive effect on the accuracy rate, this also varied depending on the virus under analysis. Finally, scaling data before prediction also has a small positive effect on the accuracy rate for this dataset. A graphical analysis of the distribution of accuracy rates across ensembles supports these findings.

Conclusions

Laboratories looking to include machine learning as part of their decision support processes need to be aware that the infection outcome, the machine learning method used and the virus type interact to affect the enhanced laboratory diagnosis of hepatitis virus infection, as determined by primary immunoassay data in concert with multiple routine pathology laboratory variables. This awareness will lead to the informed use of existing machine learning methods, thus improving the quality of laboratory diagnosis via informatics analyses.

Human immunodeficiency virus prevalence, incidence, and residual transmission risk in first-time and repeat blood donations in Zimbabwe: implications on blood safety

BACKGROUND

National Blood Service Zimbabwe human immunodeficiency virus (HIV) risk management strategy includes screening and discarding of first-time donations, which are collected in blood packs without an anticoagulant (dry pack). To evaluate the impact of discarding first-time donations on blood safety the HIV prevalence, incidence, and residual risk in first-time and repeat donations (wet packs) were compared.

STUDY DESIGN AND METHODS

Donor data from 2002 to 2010 were retrieved from a centralized national electronic donor database and retrospectively analyzed. Chi-square test was used to compare HIV prevalence with relative risk (RR), and the RR point estimates and 95% confidence interval (CI) are reported. Trend analysis was done using Cochran-Armitage trend test. HIV residual risk estimates were determined using published residual risk estimation models.

RESULTS

Over the 9 years the overall HIV prevalence estimates are 1.29% (n = 116,058) and 0.42% (n = 434,695) for first-time and repeat donations, respectively. The overall RR was 3.1 (95% CI, 2.9-3.3; p < 0.0001). The overall mean residual transmission risk of HIV window phase donations in first-time was 1:7384 (range, 1:11,308-1:5356) and in repeat donors it was 1:5496 (range, 1:9943-1:3347).

CONCLUSION

The significantly high HIV prevalence estimates recorded in first-time over repeat donations is indicative of the effectiveness of the HIV risk management strategy. However, comparable residual transmission risk estimates in first-time and repeat donors point to the need to further review the risk management strategies. Given the potential wastage of valuable resources, future studies should focus on the cost-effectiveness and utility of screening and discarding first-time donations.

Residual Risk of Hepatitis-B-Infected Blood Donations: Estimation Methods and Perspectives

Despite a considerable reduction of the risk of HBV-infected blood donation entering blood supply (residual risk) due to improved screening by HBV NAT in the developed countries, the bulk of the people with HBV living in the developing countries still needs to be screened by serologic tests such as HBsAg and anti-HBc. Many of these countries lack resources for implementing NAT and are likely to remain so in the next decade or longer, thus depending on the HBV residual risk monitoring based on serologic testing and corresponding estimation methods. This paper reviews main HBV residual risk findings worldwide and the methods based on serology used for their calculation with repeat donors, as well as their extension to the first-time donors. Two artificial datasets with high (4.36%) and low (0.48%) HBV prevalence were generated to test the performance of five methods: the original incidence/window-period model based solely on HBsAg, its modification by Soldan in 2003, the Müller-Breitkreutz model, the HBsAg yield model, and its extension to include anti-HBc seroconversions within a year. The last model was closest to the true values of residual risk and had smallest variation of the estimates in both high and low prevalence data. It may be used for residual risk evaluation in relatively small samples, such as regional blood banks data.

Blood safety and availability: continuing challenges in China's blood banking system

Social and economic development, along with increased health care coverage, has caused a sharp increase in the clinical demand for blood in China. Whole blood collection has increased rapidly in the past decade but has failed to keep pace with the ever-increasing demand. Overall, the country's blood safety has been improved with 99% of whole blood donations collected from voluntary unpaid donors. However, the unmet clinical demand for blood and the increasing incidence of human immunodeficiency virus and syphilis in the general population pose new challenges to China's blood banking system. To ensure a safe and adequate blood supply, continued efforts are required to recruit and retain a sufficient number of low-risk voluntary blood donors, improve donor prescreening and blood testing process, ease donor restrictions, and strengthen patient blood management.

Blood screening for human immunodeficiency virus: a new algorithm to reduce the false-positive results

OBJECTIVES

The objectives to this study were to evaluate the performance of an anti-human immunodeficiency virus (HIV) blood screening test and propose a new screening algorithm for blood banks routinely using nucleic acid amplification testing (NAT) to reduce false-positive results.

BACKGROUND

Most anti-HIV enzyme-linked immunosorbent assay (ELISA) results are false-positive because of the low prevalence of HIV infection and high sensitivity of the ELISAs.

METHODS/MATERIALS

A total of 281 588 voluntary donations were collected and sera reactive on one or both anti-HIV ELISAs were confirmed by Western blot (WB) testing. All samples with nonreactive results for the two ELISAs underwent NAT. A confirmed HIV-1-positive result was defined by a reactive result on NAT or WB testing. Correlations between signal-to-cutoff ratios and the confirmed HIV-1 infection rate were analysed for each enzyme immunoassay and two-enzyme immunoassay combination. The positive predictive values (PPVs) of the current and proposed algorithms were calculated.

RESULTS

Seventy-nine donations (13·9%) were positive on WB analysis and one donation negative for anti-HIV antibody was reactive on NAT and confirmed to be a window period donation on additional follow-up testing. The PPV of the 567 donations reactive on one or two ELISAs was 13·9%. However, using the new screening algorithm, 457 donations underwent NAT immediately instead of WB testing. Only 110 donations were tested with WB and the PPV was 71·8%.

CONCLUSION

Screening for HIV is sensitive, specific and time saving for donors with this algorithm, which is suitable for HIV screening in low prevalence settings.

The prevalence and trends of transfusion-transmissible infectious pathogens among first-time, voluntary blood donors in Xi'an, China between 1999 and 2009

OBJECTIVES

The prevalence of infectious diseases is increasing in developing countries, and this may threaten the biological safety of donated blood. This study analyzed trends in the prevalence of transfusion-transmissible infectious pathogens among Chinese, first-time, voluntary blood donors from 1999 to 2009 to evaluate the potential for disease transmission.

METHODS

From 1999 to 2009, all first-time donors at the Xi'an Blood Service (XBS) were screened for hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis infections using enzyme-linked immunosorbent assays (ELISA); results were confirmed using alternative commercial kits. The prevalence and temporal trends were analyzed using the Cochran-Armitage trend test and other appropriate methods.

RESULTS

From 1999 to 2009, 263 299 first-time blood donors were analyzed. The overall prevalence rates were 1.16% for HBV, 0.51% for HCV, 0.02% for HIV, and 0.31% for syphilis. There was a significant decrease in the trend for HBV and HCV infections, while a significant increase was found for syphilis. The prevalence of HIV infection remained low and stable during the study period.

CONCLUSIONS

These findings suggest that HBV infection is the primary threat to blood safety, while the increasing prevalence of syphilis might also be a potential threat.

Prevalence and prevalence trends of transfusion transmissible infections among blood donors at four Chinese regional blood centers between 2000 and 2010

Background

In China, high prevalence of HBV and HCV parallels with the growing epidemic of syphilis and HIV in the general population poses a great threat to blood safety. This study investigated the prevalence of serologic markers for transfusion transmissible infections (TTIs) among four Chinese blood centers.

Methods

We examined whole blood donations collected from January 2000 through December 2010 at four Chinese blood centers. Post-donation testing of TTIs (HIV, HBV, HCV and syphilis) were conducted using two different enzyme-linked immunosorbent assay kits for each seromarker. The prevalence of serologic markers for TTIs (%) was calculated and additional analysis was conducted to examine donor characteristics associated with positive TTIs serology.

Results

Of the 4,366,283 donations, 60% were from first-time donors and 40% were from repeated donors. The overall prevalence of HIV, HBsAg, HCV and syphilis was 0.08%, 0.86%, 0.51% and 0.47%, respectively. The prevalence profile of TTIs varied among different blood centers and appeared at relatively high levels. Overall, the prevalence of HBsAg and HCV demonstrated a decline trend among four blood centers, while the prevalence of HIV and syphilis displayed three different trends: constantly steady, continually increasing and declining among different centers.

Conclusions

This study reflects the risk of TTIs has been greatly reduced in China, but blood transfusion remains an ongoing risk factor for the spread of blood-borne infections, and further work and improvements are needed to strengthen both safety and availability of blood in China.

Two cases of transfusion-transmitted hepatitis B virus (HBV) infection in a low-endemic country before implementation of HBV nucleic acid testing

BACKGROUND

The risk of hepatitis B virus (HBV) transmission by transfusion is higher than that of other blood-borne viruses. In France, before the introduction of HBV nucleic acid testing (NAT) in 2010, blood donations were tested for hepatitis B surface antigen (HBsAg) and antibodies against hepatitis B core antigen, and the residual risk of HBV transfusion related to preseroconversion acute phase was estimated at 0.54 per million donations. The additional value of the implementation of a highly sensitive HBV NAT to prevent such transmissions is discussed.

STUDY DESIGN AND METHODS

Two lookback investigations based on HBV seroconversion of repeat donors were performed. Donors and recipients were followed up in multiple samples that were tested for HBV serologic and molecular markers.

RESULTS

The recipients have shown posttransfusion HBsAg seroconversion. The archived samples from the implicated donations were positive for HBV DNA at extremely low viral load in both cases. HBV isolates from donors and recipients of each case were organized in the same cluster with 100% identities into Genotypes A2 and B4, respectively. One recipient spontaneously recovered from infection while the second was successfully treated.

CONCLUSION

The present cases highlight the importance of introducing highly sensitive HBV NAT to prevent transmission. Moreover, the lookback studies based on appropriate molecular and serologic investigations of patients transfused with previous donations from newly identified HBV-infected repeat donors offer the opportunity to treat a recently infected recipient.

Hepatitis B surface antigen variants in voluntary blood donors in Nanjing, China

Background

Hepatitis B virus (HBV) is still one of the serious infectious risks for the blood transfusion safety in China. One plausible reason is the emergence of the variants in the major antigenic alpha determinant within the major hydrophilic region (MHR) of hepatitis B surface antigen (HBsAg), which have been assumed to evade the immune surveillance and pose a challenge to the disease diagnosis. It is well documented that some commercial ELISA kits could detect the wild-type but not the mutant viruses. The high prevalence of HBV in China also impaired the application of nucleic acid testing (NAT) in the improvement of blood security. Molecular epidemiological study of HBsAg variations in China is still limited. This study was designed to identify the prevalence of mutations in the HBsAg in voluntary blood donors in Nanjing, China.

Methods

A total of 20,326 blood units were enrolled in this study, 39 donors were positive for HBV S gene in the nested-PCR. Mutations in the major hydrophilic region (MHR; aa 99-169) were identified by direct sequencing of S region.

Results

Among of 20,326 blood units in the Red Cross Transfusion Center of Nanjing from October 2008 to April 2009, 296 samples (1.46%, 296/20,326) were HBsAg positive in the 2 successive rounds of the ELISA test. In these HBsAg positive units, HBV S gene could be successfully amplified from 39 donors (13.18%, 39/296) in the nested-PCR. Sequence analysis revealed that 32 strains (82.1%, 32/39) belong to genotype B, 7 strains (17.9%, 7/39) to genotype C. Besides well known G145R, widely dispersed variations in the MHR of S region, were observed in 20 samples of all the strains sequenced.

Conclusions

HBV/B and HBV/C are dominant in Nanjing, China. The mutations in the MHR of HBsAg associated with disease diagnosis are common.

Reducing the risk of hepatitis B virus transfusion-transmitted infection

Before 1970, approximately 6% of multi-transfused recipients acquired a transfusion-transmitted Hepatitis B virus (HBV) infection. The safety improvements since then have been tremendous. From a level of a few infections per 1000 donations, the risk today, depending on the screening algorithm and additional measurements performed, has decreased to around 1:500,000 to 1:1,000,000, an improvement greater than 1000-fold compared to 50 years ago. This enormous gain in safety has been achieved through many factors, including development of increasingly more sensitive Hepatitis B antigen (HBsAg) assays; the adoption in some countries of hepatitis B core antibody (anti-HBc) screening; an improved donor selection procedure; HBV vaccination programs; and finally the introduction of HBV nucleic acid testing (NAT). Because there is a tendency in transfusion medicine to add one safety measure on top of another to approach the ultimate goal of zero risks, costs become increasingly a matter of debate. It is obvious that any new measure in addition to existing methods or measures will have very poor cost effectiveness. Therefore each country needs to perform its own calculation based on the country’s own epidemiology, resources, political and public awareness of the risks, in order to choose the correct and most cost-efficient measures. Ideally, each country would make decisions regarding implementation of additional blood safety measures in the context of both the perceived benefit and the allocation of overall health care resources.

Prevalence and trend of hepatitis C virus infection among blood donors in Chinese mainland: a systematic review and meta-analysis

BACKGROUND

Blood transfusion is one of the most common transmission pathways of hepatitis C virus (HCV). This paper aims to provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for HCV infection among blood donors in Chinese mainland, so as to help make prevention strategies and guide further research.

METHODS

A systematic review was constructed based on the computerized literature database. Infection rates and 95% confidence intervals (95% CI) were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models. Data manipulation and statistical analyses were performed using STATA 10.0 and ArcGIS 9.3 was used for map construction.

RESULTS

Two hundred and sixty-five studies met our inclusion criteria. The pooled prevalence of HCV infection among blood donors in Chinese mainland was 8.68% (95% CI: 8.01%-9.39%), and the epidemic was severer in North and Central China, especially in Henan and Hebei. While a significant lower rate was found in Yunnan. Notably, before 1998 the pooled prevalence of HCV infection was 12.87% (95%CI: 11.25%-14.56%) among blood donors, but decreased to 1.71% (95%CI: 1.43%-1.99%) after 1998. No significant difference was found in HCV infection rates between male and female blood donors, or among different blood type donors. The prevalence of HCV infection was found to increase with age. During 1994-1995, the prevalence rate reached the highest with a percentage of 15.78% (95%CI: 12.21%-19.75%), and showed a decreasing trend in the following years. A significant difference was found among groups with different blood donation types, Plasma donors had a relatively higher prevalence than whole blood donors of HCV infection (33.95% vs 7.9%).

CONCLUSIONS

The prevalence of HCV infection has rapidly decreased since 1998 and kept a low level in recent years, but some provinces showed relatively higher prevalence than the general population. It is urgent to make efficient measures to prevent HCV secondary transmission and control chronic progress, and the key to reduce the HCV incidence among blood donors is to encourage true voluntary blood donors, strictly implement blood donation law, and avoid cross-infection.

Control of hepatitis B in China: prevention and treatment

A high rate of chronic HBV infection in China is mainly the result of perinatal or early childhood transmission. Therefore, universal vaccination against HBV in infants has been very successful in the control of chronic HBV infection, with the prevalence of hepatitis B surface antigen decreasing from nearly 10% to approximately 7% in the general population. Adoption of Good Clinical Practice and proper conduction of well-designed clinical trials on conventional and pegylated interferons and nucleos(t)ide analogs have generated important clinical data. The publication and promotion of the evidence-based national guidelines have greatly improved the standard of clinical practice on the prevention and treatment of chronic hepatitis B. The ongoing national key scientific projects on the optimization of vaccination strategy and current anti-HBV therapy will yield important clinical evidence. Inclusion of conventional and pegylated interferons and nucleos(t)ides into the new national reimbursement list will increase the availability and affordability of anti-HBV therapies, thereby further decreasing the morbidity and mortality associated with chronic HBV infection.

Detection of hepatitis B virus DNA among accepted blood donors in Nanjing, China

BACKGROUND

Posttransfusion hepatitis B virus (HBV) infection still occurs although its incidence has been substantially reduced since the introduction of screening of hepatitis B surface antigen (HBsAg) in blood donors. This study aimed to investigate the occult HBV infection in accepted blood donors in Nanjing, China.

RESULTS

The lower detection limit of the nested PCR in this study was estimated to be 20 copies/ml HBV DNA. The positive rate of occult HBV infection was 0.13% (5 of 2972) in the accepted blood donors. Sequencing data showed that the amplified HBV sequences were not identical each other and to the known sequences cloned in our laboratory, excluding the false-positive caused by cross-contamination. Phylogenetic analysis showed that the HBV in all five donors was genotype B; a single base deletion was detected in the S region of HBV DNA from one donor, and no mutation was observed in the "a" determinant of HBsAg from four other donors. All five donors were negative for anti-HBs and one was positive for anti-HBc.

CONCLUSIONS

The prevalence of occult HBV infection in the accepted blood donors in Nanjing, China is relatively high. The data would be meaningful in adapting strategy to eliminate posttransfusion HBV infection in China.

The seroprevalence of hepatitis C virus (HCV) among 559,890 first-time volunteer blood donors in China reflects regional heterogeneity in HCV prevalence and changes in blood donor recruitment models

BACKGROUND

A decrease in the prevalence of hepatitis C virus antibody (anti-HCV) has been reported among voluntary blood donors in some regions of China. However, the prevalence of HCV among volunteer blood donors in other regions of China has not been reported. The aim of this study was to investigate the seroprevalence of HCV among 559,890 first-time volunteer blood donors recruited during 2004 through 2007 at the Guangzhou Blood Center, China.

STUDY DESIGN AND METHODS

Anti-HCV was detected using two different third-generation enzyme immunoassay kits. HCV RNA was detected using reverse transcription-polymerase chain reaction (RT-PCR) targeting the 5'-untranslated region of HCV.

RESULTS

Among 559,890 donors, 1877 (0.335%) were positive for anti-HCV. The anti-HCV+ rate was significantly higher in males than females (0.37% vs. 0.28%; p < 0.001) and significantly lower among donors living in Guangdong Province than donors who had migrated from other locations (0.30% vs. 0.40%; p < 0.001). Among the 1877 anti-HCV+ donors, 450 were randomly selected for HCV nucleic acid amplification by RT-PCR. Of these, 270 (60%) were HCV RNA+ and 180 (40%) were HCV RNA-.

CONCLUSIONS

Many donors from outside Guangdong Province were migrant laborers from other areas in China, suggesting that there is regional heterogenicity in HCV prevalence within China. The overall anti-HCV+ rate reported here is among the lowest reported among blood donors in China reflecting the effect of the current recruitment of exclusively volunteer donors.

Epidemiology and prevention of hepatitis B virus infection in China

The concept of a hepatitis B vaccine was first introduced into China in 1978. China has been one of the first two developing countries to enact the universal hepatitis B vaccination programme for newborn babies in 1992, and has made tremendous achievements in the control of hepatitis B virus (HBV) infection since then. China now has both low and high endemic regions regarding HBV prevalence co-existing. Although China's drive to stop HBV spread has resulted in changes in HBV epidemic patterns, for the eventual elimination HBV infection in China, it is important to understand the current status of its epidemiology and the aspects of HBV transmission in different regions. More efforts are needed to improve and develop strategies for the control of HBV infection in China, particularly after implementing the policy of universal HBV immunization for all newborns.

Safety of the blood supply in a rural area of China

OBJECTIVE

To determine the sensitivity and specificity of tests for hepatitis B surface antigen (HbsAg), hepatitis C virus (HCV), and syphilis conducted by laboratories of 3 blood collection organizations in a rural area of China.

METHODS

From October to December 2003, 1068 samples were collected from blood donors presenting to the 3 collection centers. All samples were tested twice using 2 different test kits for HBsAg, HCV, and syphilis. An aliquot was sent to the China National Center for Clinical Laboratories to confirm the local test results. Sensitivities and specificities of the 3 local blood centers/banks were calculated using the results of the National Center for Clinical Laboratories as the gold standard.

RESULTS

The sensitivity of the 3 blood collection center/banks ranged from 0% to 63.2% for HBsAg. For HCV, the sensitivity was 0%, and for syphilis, ranged from 0% to 85.7%. There were no HBsAg positives in one of the blood center/banks, and no syphilis positives in the other. Thus, sensitivity could not be measured for these tests in these 2 facilities. Combining all 3 tests, the overall sensitivity was 55.6%. The specificity was 100%.

CONCLUSIONS

The sensitivity of the local laboratories was inadequate and could cause possible infection for an unacceptable number of blood recipients. Action needs to be taken to improve the quality of testing to ensure the safety of the rural blood supply.

Health care-associated transmission of hepatitis B and C in oncology care

The risk of acquiring hepatitis B and C in the oncology setting was historically high and predominantly related to blood product administration in the prescreening era. With the development of progressively more sophisticated testing for hepatitis B and C, breaches in infection control have played an increasingly prominent role in disease transmission. Optimizing infection control in inpatient and outpatient oncology settings is essential in preventing the health care-associated transmission of hepatitis B and C to oncology patients.

Management of hepatocellular carcinoma in Asia: consensus statement from the Asian Oncology Summit 2009

Asia has a disproportionately large share of the world's hepatocellular carcinoma (HCC), mainly because of the endemic status of chronic hepatitis B and C viruses, which leads to liver cirrhosis and an increased risk of HCC. This etiological factor presents important opportunities for prevention, early detection, diagnosis, and treatment of HCC. This consensus statement reviews the available medical evidence for management of HCC in Asia, and gives treatment recommendations that are adapted to resource availability in this diverse region with disparate health-care delivery systems.

Prevalence and trends of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus among blood donors in Iran, 2004 through 2007

BACKGROUND

Evaluation and monitoring the prevalence of transfusion-transmissible viral infections in blood donors is a valuable index of donor selection and blood safety. This study analyzed the trends of blood-borne infections among Iranian blood donations during 4 years.

STUDY DESIGN AND METHODS

Viral screening results of 6,499,851 allogeneic donations from 2004 through 2007 were analyzed. All donations were screened for hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis. The prevalence of HBV, HCV, and HIV infections per 100,000 donations and 95% confidence interval was calculated. The p value was estimated by chi-square test.

RESULTS

The prevalences of HBV, HCV, and HIV decreased during the 4-year study from 2004 through 2007. The overall prevalence was 0.56% for HBV, 0.004% for HIV, and 0.13% for HCV. There was a significant and impressive decrease in hepatitis B surface antigen prevalence from 0.73% in 2004 to 0.41% in 2007. The prevalence of HIV appeared to have decreased from 0.005% in 2004 to 0.004% in 2007 although the decrease was not significant. HCV prevalence showed a slight decline in blood donations from 0.14% in 2005 to 0.12% in 2007.

CONCLUSION

The trends of transfusion-transmitted infection prevalence in Iranian blood donations suggest that most of the safety measures employed in recent years in Iran have been effective.

Transfusion-transmitted hepatitis B virus infection

Hepatitis B virus (HBV) remains a major risk of transfusion-transmitted infection due to the pre-seroconversion window period (WP), infection with immunovariant viruses, and with occult carriage of HBV infection (OBI). Reduction of HBV residual risk depends upon developing more sensitive HBV surface antigen (HBsAg) tests, adopting anti-HBc screening when appropriate, and implementing HBV nucleic acid testing (NAT), either in minipools or more efficiently in individual samples. HBV NAT combines the ability to significantly reduce the window period and to detect occult HBV carriage substantiating decades of clinical observation that HBsAg-negative/anti-HBc-positive blood could transmit HBV. Clinical observations suggest limited transmission rate of occult HBV compared to WP. Low transmission rate might be related to low viral load observed in OBIs or to the presence of mutants associated with occult carriage. OBIs carrying detectable anti-HBs ( approximately 50%) are essentially not infectious by transfusion. However, recent data suggest that the neutralizing capacity of low anti-HBs may be inefficient when overcome by exposure to high viral load. Anti-HBc blood units without detectable anti-HBs appear moderately infectious except in immunocompromised recipients. Immunodeficient elderly and patients receiving immunosuppressive treatments may be susceptible to infection with lower infectious dose even in the presence of anti-HBs. The immune status of blood recipients should be taken into consideration when investigating "post-transfusion" HBV infection. Pre-transfusion testing and post-transfusion long-term follow-up of recipients, and molecular analysis of the virus infecting both donor and recipient are critical to definitively incriminate transfusion in the transmission of HBV.