With the introduction of highly effective and safe therapies with next-generation direct-acting antivirals (DAAs), that act without interferon, hepatitis C virus (HCV) infection remains the only treatable chronic infectious disease.

The review aims to provide an overview of the therapy revolution with a description of specific DAAs, their mechanisms of action, a summary of the safety and efficacy of specific regimens, and a discussion of populations requiring special therapeutic approaches.

DAAs are highly effective, safe, and easy to use. However, challenges such as access to health services and loss of patients from the cascade of care, especially in groups disproportionately affected by HCV infection, such as substance abusers, make it difficult to achieve the WHO's goal of HCV elimination. The proposed strategy to combat these difficulties involves a one-step approach to diagnosing and treating the infection, the availability of long-lasting forms of medication, and the development of an effective vaccine. The aforementioned opportunities are all the more important as the world is facing an opioid epidemic that is translating into an increase in HCV prevalence. This phenomenon is of greatest concern in women of childbearing age and in those already pregnant due to treatment limitations.

Concerns about HBV reactivation (HBVr) have been raised with the introduction of DAA for HCV treatment. The aim of the study was to assess the risk of HBVr in chronic HCV patients during or after DAA.

A cohort of 166 chronic HCV patients who were treated with SOF-based DAA regimens and initially positive for HBcAb total were evaluated; 10 HBsAg-positive, 156 had past HBV exposure (HBsAg-negative/HBcAb-positive). Laboratory investigations, including liver functions tests, HBV-DNA, LSM by Transient elastography, and ARFI together with serum markers of fibrosis; APRI and FIB-4 were done at baseline and after 12 weeks of DAAs therapy. HBV-DNA levels and liver functions were monitored for assessment of HBVr.

Virological HBVr was diagnosed by ≥ 1 log10 IU/ml HBV-DNA levels in 2/166 patients (1.2%) among the whole HCV cohort, who were initially positive for HBsAg; 20%. Clinical HBVr (>3 folds liver enzyme elevation) was detected in one patient with virological HBVr. Conversely, none of past HBV-infected patients experienced HBVr. All patients achieved SVR12 and had a significant decline in serum transaminases, bilirubin, APRI, and LSM measurements after HCV eradication.

HBVr might be considered after successful eradication of HCV following DAAs therapy, especially among patients who are positive for HBsAg, while past HBV infection does not seem to be a predisposing condition to HBVr.

The global burden of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and coinfection represents a major public health concern, particularly in resource-limited settings. Elimination of HCV by 2030 has become foreseeable, with effective direct-acting antiviral oral therapies and the availability of affordable generics in low-and-middle-income countries (LMICs). However, access to oral nucleos(t)ide therapy for HBV remains critical and is limited outside the existing global HIV program platforms despite affordable prices. Prevention of mother-to-child transmission of HBV through scaling up of birth dose implementation in LMICs is essential to achieve the 2030 elimination goal. Most individuals living with HBV and/or HCV in resource-limited settings are unaware of their infection, and with improved access to medications, the most significant barrier remains access to affordable diagnostics and preventive strategies. The coronavirus disease 2019 pandemic interrupted hepatitis elimination programs, albeit offered opportunities for improved diagnostic capacities and raised political awareness of the critical need for strengthening health care services and universal health coverage. This review underpins the HBV and HCV management challenges in resource-limited settings, highlighting the current status and suggested future elimination strategies in some of these countries. Global efforts should continue to improve awareness and political commitment. Financial resources should be secured to access and implement comprehensive strategies for diagnosis and linkage to care in resource-constrained settings to fulfill the 2030 elimination goal.

The leading causes of hepatitis are viral infections, Hepatitis B virus (HBV) and Hepatitis C virus (HCV). Millions of people have been infected with these deadly viral infections worldwide, and in Pakistan, every tenth person is infected with these viruses. Different populations respond with different rates to infectious diseases due to host genomic differences. To evaluate and compare the biochemical parameters in different types of hepatitis (Hepatitis B, C, and Co-infection) and different ethnic groups, a total of 200 pre-screened patients were recruited from District Headquarters Teaching Hospital Dera Ismail Khan and Tank. Blood samples (5ml) were taken from patients and were assayed for biochemical parameters, including four liver function tests (LFTs) and two renal function tests (RFTs). In 200 patients, the mean scores of Alanine transaminase (ALT) were 376±335, 315±265, and 478±519 IU/L in HBV, HCV, and co-infected patients, respectively. Moreover, the mean score of ALT was 31±7.2 IU/l in the normal control group. All other biochemical parameters demonstrated elevated levels in co-infection, HBV, and HCV, respectively, except total proteins. The RFTs showed a threshold or upper normal limit (UNL); nonetheless, when compared to normal control subjects, RFTs parameters were high in infected patients, as compared to normal control. Ethnicity wise comparison of parameters indicated that Pushtoon ethnic group indicated a high degree of severity of HBV infection and co-infection, as compared to Saraiki and Rajpoot ethnic groups, while Saraiki ethnic group showed a higher severity of HCV than both of Pushtoon and Rajpoot. Rajpoot ethnic group was least affected than both Pushtoon and Saraiki ethnic groups. Co-infected patients were more severely affected, as compared to HBV and HCV patients. The ethnicity-wise study provided evidence that different ethnic groups showed different degrees of severity. There may be some genetic background involved in hepatitis B and C viral infection due to which all three ethnic groups showed different degrees of severity. In gender-wise comparisons, male patients were more affected than female patients.

Viral interference, originally, referred to a state of temporary immunity, is a state whereby infection with a virus limits replication or production of a second infecting virus. However, replication of a second virus could also be dominant over the first virus. In fact, dominance can alternate between the two viruses. Expression of type I interferon genes is many times upregulated in infected epithelial cells. Since the interferon system can control most, if not all, virus infections in the absence of adaptive immunity, it was proposed that viral induction of a nonspecific localized temporary state of immunity may provide a strategy to control viral infections. Clinical observations also support such a theory, which gave credence to the development of superinfection therapy (SIT). SIT is an innovative therapeutic approach where a non-pathogenic virus is used to infect patients harboring a pathogenic virus. For the functional cure of persistent viral infections and for the development of broad- spectrum antivirals against emerging viruses a paradigm shift was recently proposed. Instead of the virus, the therapy should be directed at the host. Such a host-directed-therapy (HDT) strategy could be the activation of endogenous innate immune response via toll-like receptors (TLRs). Superinfection therapy is such a host-directed-therapy, which has been validated in patients infected with two completely different viruses, the hepatitis B (DNA), and hepatitis C (RNA) viruses. SIT exerts post-infection interference via the constant presence of an attenuated non-pathogenic avian double- stranded (ds) RNA viral vector which boosts the endogenous innate (IFN) response. SIT could, therefore, be developed into a biological platform for a new "one drug, multiple bugs" broad-spectrum antiviral treatment approach.

Although many people who use drugs meet criteria for vaccination against hepatitis A virus (HAV) and hepatitis B virus (HBV), estimates of susceptibility (ie, lack of immunity) are not well established. This study sought to identify the prevalence of and characteristics associated with HAV and HBV susceptibility among people who use drugs attending an urban syringe services program.

We initiated this seroprevalence study in 2018 among 438 clients of a syringe services program who met study criteria, including provision of a blood specimen and a self-reported history of drug use. We assessed HAV and HBV susceptibility and infection via serological testing. We examined associations between participant characteristics and serology status by using descriptive statistics and multivariable logistic regression models.

Of the initial 438 clients identified, 353 (80.6%) met study criteria. Of 352 participants with conclusive HAV test results, 48.6% (n = 171) were HAV susceptible; of 337 participants with conclusive HBV test results, 32.6% (n = 110) were HBV susceptible, 24.3% (n = 82) showed evidence of past or present HBV infection, and 43.0% (n = 145) had vaccine-derived immunity. Compared with participants born before 1970, participants born during 1980-1989 had 5.90 (95% CI, 2.42-14.40) times the odds of HAV susceptibility and 0.18 (95% CI, 0.06-0.53) times the odds of HBV susceptibility, and participants born during 1990-1999 had 6.31 (95% CI, 2.34-17.00) times the odds of HAV susceptibility. Decreased odds of HAV susceptibility were associated with homelessness (adjusted odds ratio = 0.48; 95% CI, 0.28-0.82).

Despite applicable HAV and HBV vaccination recommendations, substantial gaps exist in HAV and HBV susceptibility among a population of people who use drugs. These findings highlight the need for increased HAV and HBV vaccination efforts among people who use drugs.

The biotherapeutic type I interferons (IFN-I) are indicated to treat several diseases. These products are regulated to guarantee safety and efficacy through critical quality attributes. For this purpose, the development of robust assays is required, followed by its validation to demonstrate their suitability for its intended purpose. Despite there are some commercial kits to evaluate IFN-I signaling, these are focused on measuring in vitro biological response instead of their validation, which is a pharmaceutical industry requirement. The aim of this work was to validate the HEK-Blue IFN-α/β system evaluating the biological activity of IFN-α/β under good laboratory practices, according to international standards. Our results demonstrated that HEK-Blue IFN-α/β system comply with accuracy (r2>0.95) precision (CV < 20%) and specificity for both IFN-α/β; confirming that this assay is robust for this biotherapeutics' evaluation. Thereby, this bioassay could be implemented as a complementary method to the classical anti-proliferative and anti-viral assays under quality control environments.