Occult HBV infection in HIV-infected adults and evaluation of pooled NAT for HBV

Occult hepatitis B virus infection and current perspectives on global WHO 2030 eradication

The current World Health Organization (WHO) Hepatitis Elimination Strategy suffers from lack of a target for diagnosing or expunging occult HBV infection. A sizable segment of the global population has an undetected HBV infection, particularly the high-risk populations and those residing in countries like India with intermediate endemicity. There is growing proof that people with hidden HBV infection can infect others, and that these infections are linked to serious chronic hepatic complications, especially hepatocellular carcinoma. Given the current diagnostic infrastructure in low-resource settings, the WHO 2030 objective of obliterating hepatitis B appears to be undeniably challenging to accomplish. Given the molecular basis of occult HBV infection strongly linked to intrahepatic persistence, patients may inexplicably harbour HBV genomes for a prolonged duration without displaying any pronounced clinical or biochemical signs of liver disease, and present histological signs of moderate degree necro-inflammation, diffuse fibrosis, and hence the international strategy to eradicate viral hepatitis warrants inclusion of occult HBV infection.

Persistence and risk factors of occult hepatitis B virus infections among antiretroviral therapy-naïve people living with HIV in Botswana

Aim

This study aimed to determine the kinetics of occult hepatitis B virus infections (OBI) among people with HIV (PWH).

Methods

The study used archived plasma samples from longitudinal HIV natural history studies. We identified new OBI cases and assessed risk factors for OBI using Cox proportional hazards regression analysis.

Results

At baseline, 8 of 382 [(2.1%) (95% CI: 1.06-4.1)] samples tested positive for hepatitis B surface antigen (HBsAg+). Of the 374 HBsAg-negative samples, 76 had sufficient sample volume for HBV DNA screening. OBI positivity (OBI+) at baseline was reported in 11 of 76 [14.7 95% CI (8.3-24.1)] HBsAg-negative (HBsAg-) participants. Baseline HBsAg-negative samples with sufficient follow-up samples (n = 90) were used for analysis of newly identified OBI cases. Participants contributed 129.74 person-years to the study and were followed for a median of 1.02 years (IQR: 1.00-2.00). Cumulatively, there were 34 newly identified OBI cases from the 90 participants, at the rate of 26.2/100 person-years (95% CI: 18.7-36.7). Newly identified OBI cases were more common among men than women (61.1% vs. 31.9%) and among participants with CD4+ T-cell counts ≤450 cells/mL (p-value = 0.02). Most of the newly identified OBI cases [55.9% (19/34)] were possible reactivations as they were previously HBV core antibody positive.

Conclusion

There was a high rate of newly identified OBI among young PWH in Botswana, especially in men and in participants with lower CD4+ T-cell counts. OBI screening in PWH should be considered because of the risk of transmission, possible reactivation, and risk factors for the development of chronic liver disease, including hepatocellular carcinoma.

Nested Group Testing Procedure

We investigated the false-negative, true-negative, false-positive, and true-positive predictive values from a general group testing procedure for a heterogeneous population. We show that its false (true)-negative predictive value of a specimen is larger (smaller), and the false (true)-positive predictive value is smaller (larger) than that from individual testing procedure, where the former is in aversion. Then we propose a nested group testing procedure, and show that it can keep the sterling characteristics and also improve the false-negative predictive values for a specimen, not larger than that from individual testing. These characteristics are studied from both theoretical and numerical points of view. The nested group testing procedure is better than individual testing on both false-positive and false-negative predictive values, while retains the efficiency as a basic characteristic of a group testing procedure. Applications to Dorfman's, Halving and Sterrett procedures are discussed. Results from extensive simulation studies and an application to malaria infection in microscopy-negative Malawian women exemplify the findings.

Assessment of the feasibility of pool testing for SARS-CoV-2 infection screening

BACKGROUND

SARS-CoV-2 pandemic represented a huge challenge for national health systems worldwide. Pooling nasopharyngeal (NP) swabs seems to be a promising strategy, saving time and resources, but it could reduce the sensitivity of the RT-PCR and exacerbate samples management in terms of automation and tracing. In this study, taking advantage of the routine implementation of a screening plan on health workers, we evaluated the feasibility of pool testing for SARS-CoV-2 infection diagnosis in the presence of low viral load samples.

METHOD

Pools were prepared with an automated instrument, mixing 4, 6 or 20 NP specimens, including one, two or none positive samples. Ct values of positive samples were on average about 35 for the four genes analyzed.

RESULTS

The overall sensitivity of 4-samples and 6-samples pools was 93.1 and 90.0%, respectively. Focussing on pools including one sample with Ct value ≥35 for all analyzed genes, sensitivity decreased to 77.8 and 75.0% for 4- and 6-samples, respectively; pools including two positive samples, resulted positive in any size as well as pools including positive samples with Ct values <35.

CONCLUSION

Pool testing strategy should account the balance between cost-effectiveness, dilution effect and prevalence of the infection. Our study demonstrated the good performances in terms of sensitivity and saving resources of pool testing mixing 4 or 6 samples, even including low viral load specimens, in a real screening context possibly affected by prevalence fluctuation. In conclusion, pool testing strategy represents an efficient and resources saving surveillance and tracing tool, especially in specific context like schools, even for monitoring changes in prevalence associated to vaccination campaign.

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.

Prevalence of Overt and Occult Hepatitis B Virus Infection among HIV-Positive People Referring to Consultation Center for Behavioral Diseases, Kurdistan Province, Iran

Background

Based on evidence, human immunodeficiency virus (HIV) and hepatitis B virus (HBV) have common transmission routes; co-infection of HBV/HIV can dramatically increase disease progression. The present study aimed to determine the prevalence of overt HBV infection and occult hepatitis B virus infection (OBI) in HIV-positive people.

Methods

In this descriptive study, whole blood samples were collected from 184 HIV-positive subjects referring to the Consultation Center for Behavioral Diseases, Sanandaj, Iran, during 2014 to 2016. ELISA was used for the determination of HBV serologic markers (hepatitis B surface antigen [HBsAg] and antibodies to hepatitis B virus core antigen [anti-HBc]). To evaluate OBI, DNA was extracted only from HBsAg-negative and anti-HBc-positive samples and tested for HBV DNA by real-time PCR. Test results and patients’ data were analyzed by SPSS software.

Results

The mean age of the study population was 39.2 ± 9.4 (SD) years, of whom 140 (76%) were male. Overall, 43 (23.3%) samples were positive for HBsAg (overt HBV infection), and 50 (27.2%) for anti-HBc. Among 31 HBsAg-negative and anti-HBc-positive samples (suspected OBI), one (3.2%) sample was positive for HBV DNA (verified seropositive OBI). HBV infection was higher among males (n = 37; 86.05%), jobless people (n = 23; 53.49%), and those with an injection HIV transmission route (n = 32; 74.43%).

Conclusion

We observed a high prevalence of overt HBV and one OBI among the study population. A serologic marker such as anti-HBc indicates resolved or past HBV infection. Molecular screening for HBV is valuable for the management of HIV-infected people.

Occult hepatitis B infection in Turkish HIV-infected patients: A multicentre, retrospective, cross-sectional study, Schindler study

OBJECTIVE

Occult hepatitis B infection (OHBI) appears to have a higher prevalence in populations at high risk for hepatitis B virus (HBV) infection with concomitant liver disease. The aim was to assess the prevalence of OHBI in a sample of human immunodeficiency virus -1 positive and HBV surface antigen-negative (HIV-1+/HBsAg-) Turkish patients.

METHODS

Ten centres in Turkey were included in the study. Patients were selected on the basis of a power calculation with a known population size of HIV-positive patients and a reported prevalence of OHBI. Gender, age, occupation, place of residence, treatment and clinical status, and laboratory results, including immunodeficiency panel, antibody tests, hemogram, biochemistry, and coagulation studies were evaluated retrospectively.

RESULTS

The number of HIV-infected patients followed in these centres was 3172 and the sample population numbered 278. All 278 were HBsAg negative. The mean age of the sample was 37.2 ± 13.1 years and 235 (84.5%) were male. All but one patient (99.6%) had been treated with antiretroviral therapy. Of the 278 patients, 169 (60.6%) were positive for Anti-HBs and 125 (44.8%) were positive for Anti-HBc IgG. HIV RNA was detected in 203/278 (73%) of the patients. Four HBV DNA (1.4%) were diagnosed with OHBI. There was no significant difference in hemogram, hemoglobin or bilirubin concentrations in those with OHBI compared with the other patients.

CONCLUSION

In a representative sample of HIV+ patients from 10 Turkish centres, the prevalence of OHBI was found to be 1.4%. In HIV positive patients, it is important to identify those with OHBI for optimal clinical management and prognosis.

Molecular Diagnosis of SARS-CoV-2: Assessing and Interpreting Nucleic Acid and Antigen Tests

In this review, we summarize the current status of nucleic acid and antigen testing required for diagnosing SARS-CoV-2 infection and COVID-19 disease. Nucleic acid amplification (NAAT) and antigen-detection (Ag) tests occupy a critically important frontline of defense against SARS-CoV-2 in clinical and public health settings. In early stages of this outbreak, we observed that identifying the causative agent of a new illness of unknown origin was greatly accelerated by characterizing the nucleic acid signature of the novel coronavirus. Results from nucleic acid sequencing led to the development of highly sensitive RT-PCR testing for use in clinical settings and to informing best practices for patient care, and in public health settings to the development of strategies for protecting populations. As the current COVID-19 pandemic has evolved, we have seen how NAAT performance has been used to guide and optimize specimen collection, inform patient triage decisions, reveal unexpected clinical symptoms, clarify risks of transmission within patient care facilities, and guide appropriate treatment strategies. For public health settings during the earliest stages of the pandemic, NAATs served as the only tool available for studying the epidemiology of this new disease by identifying infected individuals, studying transmission patterns, modeling population impacts, and enabling disease control organizations and governments to make challenging disease mitigation recommendations to protect the expanding breadth of populations at risk. With time, the nucleic acid signature has provided the information necessary to understand SARS-CoV-2 protein expression for further development of antigen-based point-of-care (POC) diagnostic tests. The advent of massive parallel sequencing (ie, next generation sequencing) has afforded the characterization of this novel pathogen, informed the sequences best adapted for RT-PCR assays, guided vaccine production, and is currently used for tracking and monitoring SARS-CoV-2 variants.

Implications of Birth-Dose Vaccination against Hepatitis B Virus in Southeast Asia

The World Health Organization (WHO) South-East Asia Regional Office (SEARO) covers 11 countries with a combined population of about 2 billion people, making it the most populous of the six WHO regions. In 1992, the WHO advocated including the hepatitis B vaccine in the Expanded Program of Immunization (EPI) and vaccinating all infants and children three times within 1 year of birth (HepB3). Recently, the WHO advocate birth-dose hepatitis B vaccination (HepB-BD) as soon as possible after birth, preferably within 24 hours. In 2016, the SEARO endorsed a regional hepatitis B control goal with a target of hepatitis B surface antigen (HBsAg) seroprevalence of ≤1% among children aged ≥5 years by 2020. Of the 11 SEARO countries, four achieved this target on schedule. Out of these four countries, two countries (Bangladesh and Nepal) have not adopted HepB-BD in EPI program. On the other hand, the coverage of HepB3 is not satisfactory in some SEARO countries, including India which adopted HepB-BD but could not achieve the overall target of SEARO. Thus, it is a point of debate whether emphasis should be placed on proper implementation of HepB3 or whether a new agenda of HepB-BD should be incorporated in developing countries of SEARO. The article discusses strengthening and expanding the Hepatitis B vaccination program in SEARO countries with an emphasis on HepB and HepB-BD programs.

Asymptomatic Patient Testing After 10:1 Pooling Using the Xpert Xpress SARS-CoV-2 Assay

Objectives

Pool testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) preserves testing resources at the risk of missing specimens through specimen dilution.

Methods

To determine whether SARS-CoV-2 specimens would be missed after 10:1 pooling, we identified 10 specimens with midrange (ie, 25-34 cycles) and 10 with late (ie, >34-45 cycles) crossing threshold (Ct) values and tested these both neat and after 10:1 pooling. Final test results and Ct changes were compared.

Results

Overall, 17 of 20 specimens that contained SARS-CoV-2 were detected after 10:1 pooling with the Xpert Xpress SARS-CoV-2 Assay (Cepheid), rendering an 85% positive percentage of agreement. All 10 of 10 specimens with an undiluted Ct in the mid-Ct range were detected after 10:1 pooling, in contrast to 7 of 10 with an undiluted Ct in the late-Ct range. The overall Ct difference between the neat testing and the 10:1 pool was 2.9 cycles for the N2 gene target and 3 cycles for the E gene target. The N2 gene reaction was more sensitive than the E gene reaction, detecting 16 of 20 positive specimens after 10:1 pooling compared with 9 of 20 specimens.

Conclusions

An 85% positive percentage of agreement was achieved, with only specimens with low viral loads being missed following 10:1 pooling. The average impact on both reverse transcription polymerase chain reactions within this assay was about 3 cycles.

Incorporating the dilution effect in group testing regression

When screening for infectious diseases, group testing has proven to be a cost efficient alternative to individual level testing. Cost savings are realized by testing pools of individual specimens (eg, blood, urine, saliva, and so on) rather than by testing the specimens separately. However, a common concern that arises in group testing is the so-called "dilution effect." This occurs if the signal from a positive individual's specimen is diluted past an assay's threshold of detection when it is pooled with multiple negative specimens. In this article, we propose a new statistical framework for group testing data that merges estimation and case identification, which are often treated separately in the literature. Our approach considers analyzing continuous biomarker levels (eg, antibody levels, antigen concentrations, and so on) from pooled samples to estimate both a binary regression model for the probability of disease and the biomarker distributions for cases and controls. To increase case identification accuracy, we then show how estimates of the biomarker distributions can be used to select diagnostic thresholds on a pool-by-pool basis. Our proposals are evaluated through numerical studies and are illustrated using hepatitis B virus data collected on a prison population in Ireland.

Prevalence and genetic variability of occult hepatitis B virus in a human immunodeficiency virus positive patient cohort in Gondar, Ethiopia

BACKGROUND

Occult hepatitis B (OHB) is a major concern in HIV infected patients as it associates with a high risk of HBV reactivation and disease progression. However, data on the prevalence of OHB among HIV positive patients in Ethiopia is lacking. This study aims to determine the prevalence of OHB in HBV/HIV co-infected patients from Gondar, Ethiopia.

METHODS

A total of 308 consented HIV positive patients were recruited from the University of Gondar Teaching Hospital, Ethiopia. Clinical and demographic data of the participants were recorded. Plasma was tested for HBsAg and anti-HBc using commercial assays (Abbott Architect). In HBsAg negative anti-HBc positive patient samples, total DNA was isolated and amplified using nested PCR with primers specific to HBV polymerase, surface and pre-core/core regions, followed by Sanger sequencing and HBV mutational analysis using MEGA 7.0.

RESULTS

Of the total study subjects, 62.7% were female, median age 38.4 years, interquartile range (IQR): 18-68, and 208 (67.5%) had lifestyle risk factors for HBV acquisition. Two hundred and ninety-one study subjects were HIV+/HBsAg-, out of which 115 (39.5%) were positive for anti-HBc. Occult hepatitis B was detected in 19.1% (22/115) of anti-HBc positive HIV patients. HBV genotype D was the predominant genotype (81%) among OHB positive patients. Mutations associated with HBV drug resistance, HBV reactivation, and HCC risk were detected in 23% (5/22), 14% (3/22) and 45.5% (10/22) of patients, respectively.

CONCLUSION

This study found a high rate of occult hepatitis B in HIV patients. Further, high rates of mutations associated with HBV reactivation, drug resistance, and HCC risk were detected in these patients. These data highlighted the need for integrating OHB screening for proper management of liver diseases in HIV patients.

Challenges and Controversies to Testing for COVID-19

The coronavirus disease (COVID-19) pandemic has placed the clinical laboratory and testing for SARS-CoV-2 front and center in the worldwide discussion of how to end the outbreak. Clinical laboratories have responded by developing, validating, and implementing a variety of molecular and serologic assays to test for SARS-CoV-2 infection. This has played an essential role in identifying cases, informing isolation decisions, and helping to curb the spread of disease. However, as the demand for COVID-19 testing has increased, laboratory professionals have faced a growing list of challenges, uncertainties, and, in some situations, controversy, as they have attempted to balance the need for increasing test capacity with maintaining a high-quality laboratory operation. The emergence of this new viral pathogen has raised unique diagnostic questions for which there have not always been straightforward answers. In this commentary, the author addresses several areas of current debate, including (i) the role of molecular assays in defining the duration of isolation/quarantine, (ii) whether the PCR cycle threshold value should be included on patient reports, (iii) if specimen pooling and testing by research staff represent acceptable solutions to expand screening, and (iv) whether testing a large percentage of the population is feasible and represents a viable strategy to end the pandemic.

Sample pooling for SARS-CoV-2 RT-PCR screening

Objective

To evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of coronavirus disease 2019 (COVID-19) by using different commercial platforms for nucleic acid extraction and amplification.

Methods

A total of 3519 nasopharyngeal samples received at nine Spanish clinical microbiology laboratories were processed individually and in pools (342 pools of ten samples and 11 pools of nine samples) according to the existing methodology in place at each centre.

Results

We found that 253 pools (2519 samples) were negative and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples), we found discordant results when compared to their correspondent individual samples, as follows: in 22 of 29 pools (28 samples), minor discordances were found; for seven pools (7 samples), we found major discordances. Sensitivity, specificity and positive and negative predictive values for pooling were 97.10% (95% confidence interval (CI), 94.11–98.82), 100%, 100% and 99.79% (95% CI, 99.56–99.90) respectively; accuracy was 99.80% (95% CI, 99.59–99.92), and the kappa concordant coefficient was 0.984. The dilution of samples in our pooling strategy resulted in a median loss of 2.87 (95% CI, 2.46–3.28) cycle threshold (C_t) for E gene, 3.36 (95% CI, 2.89–3.85) C_t for the RdRP gene and 2.99 (95% CI, 2.56–3.43) C_t for the N gene.

Conclusions

We found a high efficiency of pooling strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA testing across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity and positive and negative predictive values.

Addressing the global burden of hepatitis B virus while developing long-acting injectables for the prevention and treatment of HIV

The first long-acting formulations of HIV drugs are undergoing regulatory review for use in maintenance of viral suppression in people with HIV. Although these novel drug formulations could contribute greatly to HIV treatment and prevention efforts, their lack of activity against hepatitis B virus (HBV) could limit their global impact, particularly in populations with high burdens of both HIV and HBV. An urgent need for greater investment in research and development of long-acting drugs with dual activity against HIV and HBV exists. Access to long-acting HIV drug formulations with dual activity against HBV would be transformative and have a great impact on efforts to prevent, treat, and eradicate both of these important global epidemics.