Recent and occult hepatitis B virus infections among blood donors in the United States

Implementing pathogen reduction technology while discontinuing blood donor deferral criteria for sexual risk behaviors: A simulation study

BACKGROUND

Combining pathogen reduction technology (PRT) with blood screening may alleviate concerns over the risk of transfusion-transmitted infections (TTI) and support changes in blood donor selection to potentially increase blood availability. This study aimed to estimate the residual risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) transfusion-transmission in Canada after implementing PRT, while eliminating deferrals for sexual risk behaviors.

STUDY DESIGN AND METHODS

A probabilistic approach that combined Bayesian networks with Monte Carlo simulations was used to estimate the risk of transfusing HIV-, HBV-, or HCV-contaminated blood components. Different scenarios were considered to compare the current residual risk after PRT implementation, with and without donor deferral criteria for sexual risk behaviors. Donor profiles and blood component outcomes were simulated based on a literature review including the prevalence and incidence of HIV, HBV, and HCV in the Canadian blood donor population; the use of current blood screening assays; and HIV, HBV, and HCV blood donor viral loads.

RESULTS

In the universal PRT scenario (i.e., with PRT/without deferral criteria), the estimated risks of HIV, HBV, and HCV transmission were significantly lower than those in the currently observed scenario (i.e., without PRT/with deferral criteria).

CONCLUSIONS

This risk model suggests that PRT for platelets and plasma (and eventually for RBCs when available) significantly reduces the residual risks of HIV, HBV and HCV transfusion-transmission and could enable the removal of blood donor deferral criteria for sexual risk behaviors.

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.

The prevalence of occult hepatitis B infection among the blood donors in a donation center in Beijing

Occult HBV infection (OBI) remains a potential threat for blood safety. The prevalence of OBI was investigated in a blood donation center of Chinese PLA General Hospital to improve HBV blood safety. 229446 samples from blood donors were screened by two different enzyme-linked immunosorbent assay (ELISA) kits. 78 samples were HBV DNA positive among 212134 ELISA nonreactive donor samples. The prevalence of OBI was 0.04% (76/212134). Ten samples of OBI were permitted by the donors' content for further research, and all of these were below 200IU/mL, and six of these were below 20IU/mL(6/10,60%). Genotype B and genotype C was 20% (2/10) and 80% (8/10), respectively. 16 amino acid mutations were detected in the S region of OBI, included three mutations in MHR region of S. The prevalence of OBI is rare in this donation center. These mutations we found may contribute to the multifactorial occurrence of OBI.

Evaluating the cost-effectiveness of low-level HBV DNA screening in occult hepatitis B infection donors: A study from Shandong Blood Center, China

OBJECTIVE

This study aimed to assess the efficacy of individual-donation nucleic acid testing (ID-NAT) in detecting occult hepatitis B virus infection (OBI) among anti-HBc positive blood donors, compared to minipool nucleic acid testing (MP-NAT).

METHODS

The present study analyzed data from the Shandong Blood Center in China during the period from January 2018 to June 2022, where HBsAg-negative blood donors were screened using the 6-sample minipool nucleic acid testing (6-sample MP NAT) method. NAT-positive samples underwent subsequent anti-HBc and anti-HBs testing. Approximately 5000 samples that passed the nucleic acid mixing test were randomly selected for anti-HBc testing, and over 100 anti-HBc positive samples underwent individual donor nucleic acid testing (ID-NAT). Any HBV DNA positive samples detected by ID-NAT were subsequently confirmed using alternative nucleic acid testing methods.

RESULTS

Among 220,445 HBsAg-negative blood donors, the positivity rate of HBV DNA detection using the 6-sample minipool nucleic acid testing (MP NAT) method was found to be 0.031% (69/220,445). Of the 67 HBV DNA positive samples, 55 (82.09%) and 25 (37.31%) were found to be positive for anti-HBc and anti-HBs, respectively, using the supplementary chemiluminescent microparticle immunoassay (CMIA). Among the 4797 HBsAg-negative/MP NAT-negative samples, 909 (18.95%) tested positive for anti-HBc. Further NAT testing was performed on 164 arbitrarily selected anti-HBc-positive/MP HBV DNA-negative samples, revealing a HBV DNA positivity rate of 1.22% (2/164).

CONCLUSION

Using individual donation nucleic acid testing can significantly increase the detection rate of occult hepatitis B virus infection in anti-HBc-positive blood donors, resulting in a detection rate of 0.22% (1.22 × 0.1895). This rate is 8.10 times higher than the detection rate achieved by mixed testing methods (0.031%) [calculated as (0.22 + 0.031)/0.031]. Therefore, it is recommended to perform single HBV DNA testing on anti-HBc-positive blood donors, discard plasma with weakly positive or negative anti-HBs but positive anti-HBc, or avoid transfusing anti-HBc-positive plasma to recipients with weakly positive or negative anti-HBs to prevent HBV infection.

Donated Blood Screening for HIV, HCV and HBV by ID-NAT and the Residual Risk of Iatrogenic Transmission in a Tertiary Care Hospital Blood Bank in Puebla, Mexico

Hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV) can be transmitted by blood transfusion. Most transmission occurs during the acute viremic phase (AVP), before antibody development. To reduce transmission risk, individual donor nucleic acid testing (ID-NAT) is used. In Puebla, Mexico, serological tests and ID-NAT have been applied to screen blood donors and detect individuals in AVP. In the present study, 106,125 blood donors' data in two periods (2012-2015 and 2017-2019) were analyzed. The residual risk (RR) values were calculated considering ID-NAT results. The RR for HIV was 14 in 1 million donations or 1 in 71,428, the RR for HVC was 6.8 in 1 million donations or 1 in 147,058 and, for HBV, it was 156 in 1 million donations, or 1 in 6410. Previously, it was predicted that the transmission RR of these viruses would be reduced in Mexico through better screening with NAT. The use of ID-NAT has, indeed, increased the safety of blood reserves for HIV and HCV. However, more research is needed to determine why the residual risk of HBV did not decrease as much over the study period. ID-NAT is an important complementary tool for blood donor screening that should be implemented.

Genotype Distribution and Demographic Characteristics of Hepatitis C Virus NAT Yield Cases among US Blood Donors

BACKGROUND

HCV infection rates among U.S. blood donors have been well characterized; however, few studies evaluate HCV genotypes among blood donors. Monitoring trends in disease and demographic patterns contribute to understanding the safety of the blood supply. Here we examined the demographic characteristics and the distribution of HCV genotypes/subgenotypes for nearly a 16-year period among blood donors confirmed positive for HCV RNA but antibody negative (defined as NAT yield).

METHODS

A retrospective assessment of demographic characteristics and testing data was used to determine temporal trends and geographical distribution of HCV genotypes/subgenotypes among American Red Cross blood donors confirmed positive as HCV-NAT yield.

RESULTS

From 2003-2018, 343 donors (0.38 per 100,000 donations; 95% CI, 0.35-0.43) confirmed positive as HCV-NAT-yield cases. Temporal analysis revealed a significant increase in HCV-NAT-yield cases of 54.1% between 2009-2014 (p=0.014), followed by a significant decline of 31.4% between 2015-2018 (p=0.002). Significantly more HCV-NAT-yield cases were detected among first-time donors, non-Hispanic Whites, donors aged 20-29 years, equally likely to be males as females, with the highest frequency in the South (0.52/100,000 donations). Subgenotype 1a (49.6%) was most frequent, followed by 3a (18.7%), 2b (12.5%), 1b (8.5%) and 2a (1.7%).

CONCLUSION

Voluntary non-remunerated blood donors are at low risk for HCV infection. Since 2015, the frequency of HCV-NAT-yield cases decreased despite an increase of acute HCV infection in the general population. HCV subgenotypes 1a and 3a continue to remain predominant among U.S. blood donors with recent HCV infection.

Background rate of low-level HCV RNA in anti-HCV confirmed-positive and minipool nucleic acid test-nonreactive blood donations

BACKGROUND

In 2019, the Food and Drug Administration revised the requirement for further testing of anti-HCV-reactive donations testing nucleic acid (NAT)-nonreactive via routine mini-pool (MP)-NAT. Individual donation (ID)-HCV NAT was required as a supplemental test prior to a second FDA-licensed anti-HCV assay; if ID-HCV-NAT is reactive, no further testing is required. This study investigated the rate of low-level RNA in anti-HCV-reactive donation samples prior to and following the implementation of supplemental ID-HCV NAT.

STUDY DESIGN/METHODS

A retrospective analysis was conducted on frozen plasma unit samples from 1161 anti-HCV confirmed-positive/HCV-NAT-nonreactive donations collected from December 2014 to January 2020. Samples were tested by multiple replicates on the Grifols Procleix Ultrio Elite (UE) assay and corresponding discriminatory HCV (dHCV) assay on the Procleix Panther System. Prospectively, the prevalence of low-level RNA in 2912 anti-HCV-reactive donations detected through routine screening from April 2020 through March 2021 was determined.

RESULTS

In retrospective analyses, 10 (0.86%) of 1161 plasma samples were UE reactive, of which four (0.34%) were dHCV reactive (in all replicates of UE and dHCV). Of 2912 anti-HCV-reactive donation samples testing NAT-nonreactive via routine MP-NAT, three (0.1%; 95% CI: 0.04-0.30) were dHCV reactive; 37% of the remaining samples were reactive by a second anti-HCV assay and thus serologically confirmed.

CONCLUSIONS

Retrospective and prospective analysis in comparison to earlier studies revealed that low-level HCV-RNA reactivity is decreasing over time. The very low HCV-RNA rates may be due to the widespread use of highly effective, direct-acting anti-viral treatments for those diagnosed with HCV infection.

Unexpected hepatitis B virus transmission after liver transplant from nucleic acid testing- and serology-negative liver donors who are hepatitis C viremic

The opioid epidemic has led to increased availability of organs for liver transplantation. The success of direct-acting antiviral therapy for hepatitis C (HCV) has led to the acceptance of HCV viremic donor organs. Nucleic acid testing (NAT) has led to increased detection of HCV and hepatitis B (HBV) in potential donors. A total of 36 patients underwent liver transplantation from donation after brain death donors who were HCV NAT-positive, and three of them were diagnosed with HBV several months after. All three recipients received livers from HCV viremic donors who were negative for HBV by serology and NAT. Soon after liver transplantation, HCV was treated, and all achieved sustained virologic response. They became HBV DNA-positive shortly thereafter. To date, there have been no reported cases of unexpected HBV transmission since universal donor NAT was implemented in 2013. We postulate that the inhibitory effect of HCV viremia on HBV may have prolonged the "NAT window period" in these donors beyond the 20-22 days quoted for solitary HBV infection. These cases highlight the need for more intensive and prolonged screening for HBV in recipients of livers from HCV viremic donors.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

Estimated prevalence and number of persons with isolated antibody to hepatitis B core antigen and associated occult hepatitis B, United States, 2001-2018

Persons with isolated antibody to HBV core antigen (IAHBc) may have occult HBV infection (OBI), which is associated with reactivation and potential risk for hepatocellular carcinoma and HBV transmission. We used National Health and Nutrition Examination Survey (NHANES) data to estimate US IAHBc prevalence and published studies of IAHBc-associated OBI prevalence to estimate OBI burden. During 2001-2018, IAHBc prevalence was 0.8% (approximately 2.1 million persons); OBI burden range was 35,500-83,600 persons. These data support the need for more robust estimates of IAHBc-associated OBI prevalence in the general US population.

Low rates of transfusion-transmitted infection screening in chronically transfused adults with sickle cell disease

BACKGROUND

Adults with sickle cell disease (SCD) on chronic transfusion therapy are exposed to a large volume of blood products, thus increasing their risk of transfusion-associated human immunodeficiency virus (HIV), hepatitis C (HCV), and hepatitis B (HBV).

METHODS

We performed a systematic chart review of chronically transfused SCD subjects at the Johns Hopkins Sickle Cell Center for Adults between October 2014 and September 2019 to determine our Center's adherence to the 2014 National Heart, Lung and Blood Institute (NHLBI) SCD guidelines for annual screening for Transfusion Transmitted infections (TTI) and assessed HBV immunity and HBV vaccination rates.

RESULTS

The study included 85 subjects with a median age of 34 years (23-63); 52% were female. No subject received annual screening; 68 subjects (80%) were screened for HIV, 60 subjects (71%) for HCV and 53 subjects (62%) for HBV infections at least once in the study period. Of those screened, one patient was newly diagnosed with HCV infection, and none with HIV or HBV infection. Among 31 subjects tested for anti-Hepatitis B surface antibody, 16 subjects (52%) tested negative. Nineteen (20%) subjects had HBV vaccination documented.

CONCLUSIONS

Low adherence to the NHLBI TTI screening guidelines, especially for HBV, highlights the resource intensiveness of this patient population. The low rates of anti-Hepatitis B surface antibody positivity highlight the need to confirm vaccination, provide boosters as indicated, and investigate the adults with SCD's immune response to HBV vaccination.

Hepatitis B virus prevalence in first-time blood donors in Flanders, Belgium: Impact of universal vaccination and migration

BACKGROUND

Transfusion-transmissible infections such as hepatitis B virus (HBV) remain a major concern for the safety of blood transfusion. This cross-sectional study aimed to assess the trend of HBV prevalence and associated risk factors among a first-time donor population in a low endemic country.

STUDY DESIGN AND METHODS

Between 2010 and 2018, blood samples were collected from first-time donors presented at donor collection sites of Belgian Red Cross-Flanders. They were tested for hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc), and HBV DNA, HIV and hepatitis virus C (HCV) antibodies and RNA, and syphilis antibodies.

RESULTS

A total of 211,331 first-time blood donors (43.7% males, median age 25 years) were analyzed. HBsAg prevalence decreased from 0.06% in 2010 to 0.05% in 2018 (p = .004) and this declining trend was accompanied by an increased number of donors in the HBV vaccinated birth cohort (p < .001). HBsAg prevalence was 0.33% in foreign-born donors and 0.02% in Belgian natives (p < .001). Multivariate risk profiling showed that anti-HBc positivity was significantly associated with mainly foreign-born donors (odds ratio [OR] = 9.24) but also with older age (OR = 1.06), male gender (OR = 1.32), year of blood donation (OR = 0.94), and co-infections with HCV (OR = 4.31) or syphilis (OR = 4.91).

DISCUSSION

The decreasing trend in HBV prevalence could mainly be explained by the introduction of the universal HBV vaccination. Being born in endemic areas was the most important predictor for HBV infection while the co-infections with syphilis suggest unreported sexual risk contacts.

Occult and active hepatitis B virus detection in donated blood in São Paulo, Brazil

BACKGROUND

The present study determined the HBV antigen, antibody, and DNA status in blood donations deemed to be HBV positive. Individuals with an occult HBV infection (OBI), defined as being positive for HBV DNA but negative for HBV surface antigen (HBsAg), as well as those with active infection (HBsAg-positive), were identified and characterized.

STUDY DESIGN AND METHODS

From a total pool if 198,363 blood donations, we evaluated in a cross-sectional study, 1106 samples that were positive in screening tests for antibody to HBV core antigen (HBcAb), HBsAg, and/or HBV DNA by nucleic acid testing (NAT-HBV). The presence of genetic variants in the HBV pol/S gene in individuals with an active HBV infection was also determined.

RESULTS

OBIs were detected in six of 976 samples (0.6%) that were positive only for HBcAb. The rate of HBV active infection was 0.024% (48/198,363) and there was a predominance of HBV sub-genotype A1 (62.2%, 28/45), followed by D3 (17.8%, 8/45). Mutations in the S gene were found in 57.8% (26/45) and immune escape mutations in 37.8% (17/45) of active HBV-infected donors. Among them, T123N, G145A, and D144G high-impact immune escape mutations were identified.

CONCLUSION

Highly sensitive molecular tests improve the capacity to detect OBIs. When NAT is performed in pooled samples, HBcAb test has value in the detection of donors with OBI and improves transfusion safety. Mutations in the S gene are frequent in HBsAg-positive blood, including those associated with diagnostic failure and vaccine escape mutations.

Overt and occult hepatitis B among immigrants and native blood donors in Madrid, Spain

Background:

The risk of transfusion-transmitted viral infections is very low in developed countries. Recent massive migration flows from highly hepatitis B virus (HBV), hepatitis C virus (HCV) and/or HIV endemic regions to Europe may have changed this scenario.

Methods:

During 2017 and 2018, a total of 491,753 blood donations (291,762 donors) were evaluated at the Madrid Regional Transfusion Center. All were tested for hepatitis B surface antigen (HBsAg), anti-HCV and anti-HIV, as well as for HBV-DNA, HCV-RNA and HIV-RNA.

Results:

Overall, 35 donors were positive for HIV-RNA and 26 for HCV-RNA. HBV markers were found in 111 (0.022%) donors, split out into three categories: HBsAg+ (n = 93; 0.019%), occult B infection (OBI) (n = 17; 0.003%), and acute HBV window period (n = 1; 0.0002%). All 17 OBI donors were positive for anti-HBc and confirmed as viremic in repeated testing. Viral load amounts were uniformly below 100 IU/mL. Ten OBI donors were repeated donors and look-back studies could be completed for eight of them. Fortunately, none of all prior recipients experienced transfusion transmitted hepatitis B. Compared with HBsAg+ donors, OBI donors were more frequently native Spaniards (76% versus 40%) and older (median age 52 versus 42 years old).

Conclusion:

Active HBV infection is currently found in 0.022% of blood donations (0.038% of donors) in Madrid. This rate is 3-fold greater than for HIV and/or HCV. On the other hand, HBsAg+ donors are 3-fold more frequent than OBI donors and more often immigrants than native Spaniards. No transfusion-transmitted HBV infections were identified during the study period, including retrospective checking of former recipients of OBI donors.

The distribution of hepatitis B virus surface antigen polymorphisms at positions associated with vaccine escape

Hepatitis B virus (HBV) infects over 250 million people worldwide. Vaccination is effective at preventing infection, although several mutations within the "a" determinant region of the HBV surface antigen (HBsAg) are associated with vaccine escape. We evaluated the frequency, genotype, and global distribution of polymorphisms at sites associated with vaccine escape in 4244 unique full-length HBV genomes. The "a" determinant within the Surface gene was inspected for polymorphisms at sites identified previously associated with vaccine escape. Nearly, 268 (6.3%) sequences from 36 countries contained a polymorphism at a site associated with vaccine escape including 22 genotype A, 99 genotype B, 93 genotype C, 32 genotype D, 14 genotype E, 3 genotype F, 2 genotype G, and 3 genotype I. In genotype A, the most common polymorphism occurred at M133. In genotype B, Q129 and M133 occurred 45 and 51 times, respectively, accounting for 94% of polymorphisms. Polymorphisms at G145 were most frequent in genotype C, while P120 was most common in genotype D. Among all genotypes, polymorphisms at M133 were the most common and accounted for 30.9% of polymorphisms. Polymorphisms at T116, P120, F134, K141, and P142 occurred in geographically diverse locations, whereas polymorphisms at Q129, M133, D144, and G145 were concentrated in East Asia. While the sample size is large, this approach relied on convenience sampling within each country, and many countries have no data available, thereby highlighting the need for additional routine surveillance of surface antigen mutations associated with vaccine escape.

The evolution and clinical impact of hepatitis B virus genome diversity

The global burden of hepatitis B virus (HBV) is enormous, with 257 million persons chronically infected, resulting in more than 880,000 deaths per year worldwide. HBV exists as nine different genotypes, which differ in disease progression, natural history and response to therapy. HBV is an ancient virus, with the latest reports greatly expanding the host range of the Hepadnaviridae (to include fish and reptiles) and casting new light on the origins and evolution of this viral family. Although there is an effective preventive vaccine, there is no cure for chronic hepatitis B, largely owing to the persistence of a viral minichromosome that is not targeted by current therapies. HBV persistence is also facilitated through aberrant host immune responses, possibly due to the diverse intra-host viral populations that can respond to host-mounted and therapeutic selection pressures. This Review summarizes current knowledge on the influence of HBV diversity on disease progression and treatment response and the potential effect on new HBV therapies in the pipeline. The mechanisms by which HBV diversity can occur both within the individual host and at a population level are also discussed.