Residual Risk Of Hepatitis Research Articles

Residual risk of hepatitis B virus transmission through blood donations in Burkina Faso screened with rapid diagnostic tests.

Background and Aimshepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) represent the major transfusion–transmissible pathogens worldwide. The risk of transmission is relatively high in African countries, mainly due to unreliable screening methods of blood donations. In Burkina Faso, predonation screening using rapid diagnostic tests (RDTs) is widespread, raising the major question of the transfusion safety in the country. The objective of this study was to assess the risk of transmission of HBV, HCV, and HIV through blood transfusion in the context of the use of RDTs for screening of the blood donations.MethodsIn this cross‐sectional study, a total of 417 serum samples obtained from blood donors tested negative for HBsAg, anti‐HCV, and anti‐HIV using RDTs were retested for the same markers using chemiluminescent immunologic assays. Total antibodies to HBV core (anti‐HBc) were tested on randomly selected samples. HBV‐DNA and HCV‐RNA viral loads (VLs) were quantified on HBsAg and anti‐HCV positive samples, respectively. To assess possible occult hepatitis B infection (OBI), HBV‐DNA‐VL was quantified on 313 randomly selected HBsAg‐negative samples.ResultsHBsAg and anti‐HCV were found respectively in 6 (6/417; 1.4%) and 11 (11/417; 2.6%) samples. No samples were reactive for anti‐HIV. Total anti‐HBc were detected in 217 out of the 319 randomly selected samples (217/319; 68.02%). HBV‐DNA was detected in four (4/313; 1.27%) samples, including two (2/6; 33.33%) of the six HBsAg positive samples and two (2/313; 0.6%) of the HBsAg‐negative samples, suggesting two cases of occult HBV infection. All anti‐HCV antibody‐positive samples were HCV‐RNA negative.ConclusionThis study shows that RDTs are not sufficiently sensitive for the screening of blood donations. Our results highlight the urgent need to think about the extension of sensitive immunological tests in all blood transfusion centers and also the implementation of nucleic acid amplification techniques.

The current incidence, prevalence, and residual risk of hepatitis B viral infections among voluntary blood donors in China

BackgroundThere are few data available on the prevalence, incidence, and residual risk of transfusion-transmitted HBV (TT-HBV) infections among Chinese blood donors. This study investigated the demographic characteristics of blood donors, as well as the prevalence, incidence, and residual risk (RR) of TT-HBV infections in six large blood centers in different regions of China.MethodsThe demographic characteristics and HBV screening test results of blood donors from six blood centers in different regions in China were collected and analyzed. The hepatitis B surface antigen (HBsAg) yield approach was used to estimate the incidence of HBV. Then, the RR of TT-HBV infections was evaluated using the incidence-window period model.ResultsThe majority of donors were between 18 and 35 years old (including 35), with the exception of the Changzhi Blood Center where a majority of donors were between 35 and 55 years old (including 55). The prevalences of HBV were 0.13%, 0.078%, 0.16%, 0.07%, 0.20%, 0.25% in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively. The estimated corresponding incidences were 213.44, 161.59, 989.80, 278.05, 125.31 and 352.19 per 105 person-years. Using an infectious window period of 59 days, the RR for HBV was estimated to be 34.14, 25.85, 158.35, 44.48, 20.04 and 56.35 per 105 person-years in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively.ConclusionDespite the introduction of more sensitive assays in blood screening, our data revealed that the current residual risk of TT-HBV infection was still high (overall 56.53 per 105 py). A continuous monitoring of the residual risk of transfusion-transmitted infections is crucial for safe blood management.

Incidence and Residual Risk of HIV, HBV and HCV Infections Among Blood Donors in Tehran.

Estimation of residual risk is essential to monitor and improve blood safety. Our epidemiologic knowledge in the Iranian donor population regarding transfusion transmitted viral infections (TTIs), is confined to a few studies based on prevalence rate. There are no reports on residual risk of TTIs in Iran. In present survey, a software database of donor records of Tehran Blood Transfusion Center (TBTC) was used to estimate the incidence and residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections, by applying the incidence rate/window period (IR-WP) model. A total of 1,207,155 repeat donations was included in the analysis and represented a mean of 8.4 donations per donor over 6years. The incidence amongst repeat donors was estimated by dividing the number of confirmed seroconverting donors by the total number of person-years at risk. The residual risk was calculated using the incidence/window period model. Incidence rate and residual risk for HBV, HCV and HIV infections were calculated for total (2005-2010) and two consecutive periods (2005-2007 and 2008-2010) of the study. According to the IR-WP model, overall residual risk for HIV and HCV in the total study period was 0.4 and 12.5 per million units, respectively and for HBV 4.57/100,000 donations. The incidence and residual risk of TTIs, calculated on TBTC's blood supply was low and comparable with developed countries for HIV infection but high for HCV and HBV infections. Blood safety may therefore be better managed by applying other techniques like nucleic acid amplification tests.

Evolution of the Residual Risk of Transmitting HIV, HCV and HBV in the Blood Transfusion from 1998 to 2009 in Cote d’Ivoire

Prevention of viral contamination of blood from blood bags collected remains a concern finds strategies traceability of blood products and blood safety in Cote d’Ivoire. Thus, the authors have estimated the residual risk of transmission of human immunodeficiency virus (HIV), Hepatitis B virus (HBV) and Hepatitis C (HCV) among blood donors in four periods of three years, 1998-2000, 2001-2003, 2004-2006, 2007-2009 from data collected at the blood establishments in the national territory. The determination of HIV antibodies against the hepatitis C virus and the surface antigen of hepatitis B (HBsAg) were carried out by immuno-enzymatic techniques plate (ELISA) associated with the residual risk assessment. The results showed a gradual decrease of the residual risk of HIV to be the lowest in the period 2007-2009 with 12 per 100 000 or 1 per 8333 donations. Residual risk of hepatitis B and C have known an increase during the different periods to be respectively 219 to 100 000 or 1 457 and 1180 per 100 000 or 1 per 85 donations over the period 2007-2009. The residual risk of HCV is 98 times higher than HIV and 18 times that of hepatitis B. These results show that efforts must be continued in the steps of donor selection, confirmation of screening test for viral contamination and assessment of residual risk of viral transmission during blood transfusion

Joint application of mathematic models in assessing the residual risk of hepatitis C virus transmitted through blood transfusion

The practicable and effective methods for residual risk assessment on transfusion-transmitted disease was to establish the mathematic models. Based on the characteristics of the repeat donors which donated their blood on a regular base, a model of sero-conversion during the interval of donations was established to assess the incidence of the repeat donors. Based on the characteristics of the prevalence in the population, a model of 'prevalence increased with the age of the donor' was established to assess the incidence of those first-time donors. And based on the impact of the windows period through blood screening program, a model of residual risk associated with the incidence and the length of the windows period was established to assess the residual risk of blood transfusion. In this paper, above said 3 kinds of mathematic models were jointly applied to assess the residual risk of hepatitis C virus (HCV) which was transmitted through blood transfusion in Shanghai, based on data from the routine blood collection and screening program. All the anti-HCV unqualified blood donations were confirmed before assessment. Results showed that the residual risk of HCV transmitted through blood transfusion during Jan. 1(st), 2007 to Dec. 31(st), 2008 in Shanghai was 1:101 000. Data showed that the results of residual risk assessment with mathematic models was valuable. The residual risk of transfusion-transmitted HCV in Shanghai was at a safe level, according to the results in this paper.

Transfusion transmission of hepatitis B virus: still learning more about it

Background Despite continuous technical improvement in blood donation testing, hepatitis B infection remains a major risk of transfusion‐transmitted viral infection. The residual risk of hepatitis B virus (HBV) transmission is related to the pre‐seroconversion window period (WP), infection with immunovariant viruses, and with occult carriage of HBV infection (OBI).Results and discussion Reduction of HBV residual risk is achieved by developing more sensitive HBsAg test, by adopting anti‐HBc screening when appropriate, and recently by implementing HBV nucleic acid testing (NAT), either in minipools or more efficiently in individual donations. Compared with serological testing, HBV NAT combines the ability to significantly reduce the window period and to detect OBIs. Clinical observations suggest lower transmission rate of occult HBV than WP. Lower transmission rate might be related to the low viral load generally observed in OBI donors or to the presence of defective variants associated with occult carriage. In addition, there is evidence that OBI‐infected donors carrying neutralizing anti‐HBs (∼50%) are unlikely to be infectious, while those with anti‐HBc only may be more infectious especially in immunocompromised recipients. Immunodeficient elderly and patients receiving immunosuppressive treatments (organ transplantation or cancer chemotherapy) may be susceptible to infection with lower infectious dose even in the presence of anti‐HBs. There is no evidence that blood from anti‐HBc only positive/HBV DNA‐negative donors is infectious. Present evidence suggests that the association of HBsAg and sensitive NAT screening adequately covers risks of HBV transfusion–transmission, allowing to dispense or discontinue anti‐HBc screening, avoiding discarding non‐infectious and precious blood units, particularly in high prevalence areas. Identification of ‘post‐transfusion’ HBV infection relies essentially on clinical evidence of acute infection or on look‐back exercises following the identification of HBV DNA‐positive donations. To protect from HBV infection the increasing number of immunodeficient recipients, maximum sensitivity of HBV NAT is required. As these recipients are also at risk of viral reactivation when previously exposed, anti‐HBc testing and storage of a pre‐transfusion sample when anti‐HBc‐positive would prevent the difficulties of differentiating between transfusion–transmission and reactivation.

Progress in monitoring blood safety

Progress in monitoring blood safety

Current incidence and residual risk of hepatitis B infection among blood donors in the United States

This study used two approaches to estimate the current incidence of hepatitis B virus (HBV) in a US donor population. HBV incidence was estimated through the hepatitis B surface antigen (HBsAg) yield approach and the seroconversion method. Residual risk was estimated by the incidence–window period model. HBsAg yield refers to an HBsAg confirmed-positive, antibody against hepatitis B core antigen (anti-HBc)–nonreactive donation, adjusted for false-positive neutralization results. The number of HBsAg-seroconverting repeat donors divided by total number of person-years of evaluation or the HBsAg yield rate divided by HBsAg yield window gave rise to incidence estimates. The seroconversion and the yield approach, respectively, gave an incidence estimate of 3.41 or 3.43 per 105 person-years. Using a revised infectious window period of 38 or 30 days for current HBsAg assays, the current residual risk for HBV was respectively estimated for 2006 to 2008 at 1 in 282,000 or 1 in 357,000 donations from the seroconversion approach and 1 in 280,000 or 1 in 355,000 donations from the yield approach. With the same database and methods, this is a decrease from 1 in 86,000 to 1 in 110,000 observed in 1997 to 1999. Current HBV incidence and residual risk are lower than earlier estimates, especially in the youngest donors, but remain higher in the absence of HBV nucleic acid test than those for human immunodeficiency virus or hepatitis C virus (HCV). In addition to the exclusion of HBsAg false-positive donors, the reduction could reflect shortened window periods and decreased incidence rates due to vaccination or other reasons.

Epidemiology of hepatitis B in Canadian blood donors

The residual risk of hepatitis B is higher than for other markers such as human immunodeficiency virus and hepatitis C virus in nonendemic countries. Evaluating the potential for further risk reduction requires a better understanding of the relationship between donor selection criteria, immigration from endemic countries, and public health vaccination strategies. Age and sex trends of hepatitis B surface antigen (HBsAg)-positive donors from 1997 to 2006 were analyzed using a Poisson model. All HBsAg-positive donors in 2005/2006 plus four matched control donors for every HBsAg-positive donor who participated were invited to participate in a risk factor interview and predictors of HBsAg positivity identified by logistic regression. A survey of 40,000 donors who did not react for all markers asked about vaccination history and country of birth. Most HBsAg-positive donations were from first-time donors (86%), have been decreasing in donors under the age of 30 (p < 0.01), and were correlated with geographic regions with more donors from higher-prevalence countries (p < 0001). Birth in a higher-prevalence country predicted HBsAg positivity (p < 0.01). Fifty-six percent of donors reported being vaccinated for hepatitis including approximately 80 percent of donors under age 30 who reported being vaccinated as part of regular school programs. HBsAg-positive donations are decreasing in donors under age 30, those most frequently vaccinated through provincial vaccination programs. HBsAg-positive donations largely reflect immigration from high-prevalence countries without other deferrable risk factors, mainly chronic cases that will be detected by current testing. Furthermore, risk of incident infections should decrease with increasing vaccination rates in donors, especially the younger cohort now receiving universal vaccination.

Erythropoietin and preoperative autologous blood donation in the prevention of hepatitis C infection: necessity or luxury?

Prevention of exposure to allogeneic blood transfusion during surgery is an important financial issue when recombinant human erythropoietin (rHuEPO) is used in addition to preoperative blood donation. The aim of this study was to carry out a cost-effectiveness analysis of the use of rHuEPO in preoperative blood donation in orthopedic surgery. The study, based on a decision tree analysis of the use of rHuEPO, was conducted from the perspective of the French health care system. The efficacy criterion was the number of hepatitis C infections prevented. The decision tree analysis was constructed as follows: the residual risk of hepatitis C infection was 8.26 per million units transfused, and the chance node was defined according to the number of units transfused. With the use of rHuEPO in preoperative blood donation, 0.30562 cases of hepatitis C infection per 100,000 patients were prevented. The incremental cost of one prevented hepatitis C infection amounted to $888,000,000 (US). Despite the limitations of our model, the cost-effectiveness ratio was so large that variations only slightly modified the size of the result. From the societal perspective, it was not cost-effective to add rHuEPO to preoperative blood donation.