Ribavirin Treatment Research Articles

Molecular characterisation of a rabbit Hepatitis E Virus strain detected in a chronically HEV-infected individual from Germany

In immunocompromised individuals persisting viremia frequently leads to a chronic hepatitis E virus (HEV) infection. Zoonotic transmission of HEV from pigs and wild boar to humans is proven and sporadic infections with rabbit HEV (raHEV) have recently been reported. Here, the molecular characterisation of a raHEV strain isolated from an immunocompromised, chronically HEV-infected, heart-transplanted patient is described. After successful ribavirin (RBV) treatment of a HEV infection in 2019, the patient was again tested HEV positive in 2021 and received a second RBV therapy cycle. Full-length HEV genome amplification and next generation sequencing was performed on a plasma sample taken between first and second cycle of RBV therapy and a stool sample taken two months after starting the second cycle. The sequence of plasma (raHEV-83) and stool (raHEV-99) derived virus showed the highest nucleotide sequence identity to a Chinese raHEV and a phylogenetic relationship to a raHEV strain isolated from a French patient. Furthermore, sequence analysis revealed the presence of RBV-associated substitutions V1479I and G1634K in the HEV sequences from plasma and additionally K1398R from stool. The results underline the role of rabbits as putative sources of HEV infection and emphasize the need of a one health concept for a better understanding of HEV epidemiology and to develop tools for prevention and control of HEV infection.

Epidemiology, symptoms, transmission, prevention, treatment, and future prospects of the Lassa fever outbreak: a potential study.

Epidemiology, symptoms, transmission, prevention, treatment, and future prospects of the Lassa fever outbreak: a potential study.

Investigating the effect of ribavirin treatment on genetic mutations in Crimean-Congo haemorrhagic fever virus (CCHFV) through next-generation sequencing.

Crimean-Congo haemorrhagic fever (CCHF) is the most widespread tick-borne viral haemorrhagic fever affecting humans, and yet a licensed drug against the virus (CCHFV) is still not available. While several studies have suggested the efficacy of ribavirin against CCHFV, current literature remains inconclusive. In this study, we have utilised next-generation sequencing to investigate the mutagenic effect of ribavirin on the CCHFV genome during clinical disease. Samples collected from CCHF patients receiving ribavirin treatment or supportive care only at Sivas Cumhuriyet University Hospital, Turkey, were analysed. By comparing the frequency of mutations in each group, we found little evidence of an overall mutagenic effect. This suggests that ribavirin, administered at the acute stages of CCHFV infection (at the World Health Organization-recommendeddose) is unable to induce lethal mutagenesis that would cause an extinction event in the CCHFV population and reduce viremia.

The efficacy of the direct-acting antiviral combination in hemodialysis patients with chronic hepatitis C virus Genotype 1 infection

Background Interferon and ribavirin treatments previously used in treating chronic hepatitis C virus (HCV) infection cannot be used effectively in hemodialysis patients due to dose adjustment and drug-related side effects. Direct-acting antivirals (DAAs) therapies have been reported to be effective in hemodialysis patients. This study aimed to evaluate the effectiveness of DAAs in hemodialysis patients with chronic hepatitis C.
 Material and Methods Twenty hemodialysis patients with chronic hepatitis C followed in the gastroenterology outpatient clinic between 2016 and 2018 were evaluated retrospectively.
 Results Twelve of the 20 patients were male, and eight were female. The mean age of the patients was 50.7±8.6 years. Six patients had no treatment experience. Fourteen patients had been previously treated with interferon and/or ribavirin but did not achieve sustained virological response (SVR). Genotype 1b was detected in 14 patients, genotype 1a in 4 patients, and genotype 1 in 2 patients. Patients were treated with ombitasvir/paritaprevir/ritonavir (OBV/PTV/r) and dasabuvir (DSV) or ribavirin (RBV) for 12 or 24 weeks. Two patients were cirrhotic and had a Child-Pugh score of A. Treatment was discontinued in 2 patients due to thrombus formation in the arteriovenous fistula in the first month of DAAs treatment. SVR12 was evaluated in 14 of 18 patients and found to be 100%. One of the ten patients accepted as SVR24 had a relapse. This rate of SVR24 was similar to that in the general population.
 Conclusions Our results supported that the OBV/PTV/r and DSV or RBV regimen was a safe and effective therapy for hemodialysis patients with chronic hepatitis C virus genotype 1.

Intralesional application of ribavirin in two American flamingos (Phoenicopterus ruber) with poxvirus infection

We report the successful treatment of poxvirus lesions in two juvenile American flamingos (Phoenicopterus ruber) with experimental low-dose intralesional ribavirin injection. In the first flamingo, the size and location of a beak verrucosity interfered with feeding, and after multiple surgical interventions, an experimental therapy of low-dose intralesional ribavirin was implemented with close blood parameter monitoring to minimize any potential side effects due to systemic antiviral administration. The second flamingo had a poxvirus lesion on the tibiotarsus, which recurred after unsuccessful conservative medical treatment and surgical intervention and a course of intralesional ribavirin therapy was implemented. Regression of the lesions in both flamingos commenced within 3 days of ribavirin treatment resulting in complete resolution within 6 weeks of onset of ribavirin treatment.

A Retrospective Study of Long-Term Clinical Outcomes in Patients with Chronic Hepatitis C Treated with Interferon and Ribavirin.

The key endpoint for treatment efficacy in chronic hepatitis C (CHC) is the absence of a detectable virus at 24 weeks after treatment. This study aims to determine the long-term clinical outcomes in patients with CHC after interferon and ribavirin treatment and the factors that influence them. A retrospective study was conducted on 259 patients with CHC between 2003 and 2021, and the patients were divided into treated (n = 159) and untreated (n = 100) groups. The median observation duration was four years for the treated group (range: 1-15 years) and four years for untreated groups (range: 1-14 years). The mean ages of the treated and untreated groups were 47.38 ± 9.07 and 51.17 ± 8.38 years, respectively. Regardless of whether antiviral therapy had been administered, patients with undetectable hepatitis C virus (HCV) load had a lower risk of developing liver cirrhosis and hepatocellular carcinoma (HCC) than patients with detectable HCV load (p < 0.05). Furthermore, patients with HCV genotype 1b were more likely to develop cirrhosis and HCC than patients with HCV non-genotype 1b (p < 0.05). Based on the results of multivariate analysis, age of 50 years and above (hazard ratio [HR] = 6.74, 95% confidence interval [CI] = 2.79-16.28) and infection with HCV genotype 1b (HR = 2.43, 95% CI = 1.06-5.56) were significant predictors of liver cirrhosis and HCC development, whereas undetectable HCV RNA load (HR = 0.14, 95% CI = 0.43-0.46) was a protective factor. During the long-term follow-up, no cases of HCC were discovered in patients with undetectable HCV RNA load. Nevertheless, long-term monitoring is still required in patients with liver cirrhosis, since it increases the risk for developing liver cancer.

Meta-Analysis of the Efficacy of Cimetidine in the Treatment of Mumps

Objective: To compare the efficacy of cimetidine and ribavirin in the treatment of mumps by meta-analysis. Methods: Controlled trials of cimetidine and ribavirin in the treatment of mumps were searched through China National Knowledge Infrastructure (CNKI), Wanfang data, Cqvip, Pubmed, The Cochrane Library and EMBase databases up to September 2022. The effective rate, the time of swelling regression in parotid gland area and the rate of adverse reactions were analyzed by Review Manager 5.3 software. Results: The final 10 articles included 920 children, including 427 in the trial group and 447 in the control group. Meta analysis showed that the effective rate of cimetidine in the treatment of mumps was higher than that of ribavirin in routine treatment, with a statistically significant difference (odds ratio [OR] = 5.2, P &lt; 0.00001); The time of swelling regression was statistically significant (OR = -1.28, P &lt; 0.00001); The difference of adverse reaction rate was not statistically significant (OR = 0.73, P = 0.62). Conclusions: Compared with ribavirin, cimetidine is more effective in the treatment of mumps, with shorter swelling regression time without increases of adverse reactions.

Chronic hepatitis E in an elderly immunocompetent patient who achieved a sustained virologic response with ribavirin treatment.

A woman in her late 70s was diagnosed with liver injury at a health examination. Despite treatment with ursodeoxycholic acid at a nearby hospital, her transaminase levels elevated in two peaks. She was transferred to our hospital 77days after the health examination. She weighed 42kg and had a low body mass index of 19.8kg/m2. Viral markers, including immunoglobulin A (IgA) against hepatitis E virus (anti-HEV IgA), were negative. Drug-induced liver injury was negligible. We suspected autoimmune hepatitis because of the patient's female gender and positive antinuclear antibody. However, prednisolone and azathioprine failed to completely improve her hepatitis. On day 643, anti-HEV IgA was re-evaluated and found to be positive. She was diagnosed with autochthonous chronic hepatitis E because the virus strains in the preserved serum on day 77 and the serum on day 643 had identical nucleotide sequences (genotype 3a). Following prednisolone and azathioprine discontinuation, ribavirin (RBV) was administered for 3months. HEV RNA disappeared and remained negative for more than 6months after the cessation of RBV. The HEV RNA titer of 6.2 log10 copies/mL on day 77 was unusually high 2.5months after the onset, suggesting that hepatitis E had already been chronic before immunosuppressive treatment for possible autoimmune hepatitis. After getting married at 23years old, she had been a housewife and had no comorbidities that might deteriorate her immunity. Chronicity should be kept in mind when encountering HEV infection in elderly and underweight patients.

Mechanisms of CD8+ T-cell failure in chronic hepatitis E virus infection.

In immunosuppressed patients, persistent HEV infection is common and may lead to cirrhosis and liver failure. HEV clearance depends on an effective virus-specific CD8+ T-cell response; however, the knowledge gap around HEV-specific CD8+ T-cell epitopes has hindered analysis of the mechanisms of T-cell failure in persistent infection. We comprehensively studied HEV-specific CD8+ T-cell responses in 46 patients with self-limiting (n= 34) or chronic HEV infection (n= 12), by epitope-specific expansion, functional testing, exvivo peptide HLA class I tetramer multi-parametric staining, and viral sequence analysis. We identified 25 HEV-specific CD8+ T-cell epitopes restricted by 9 different HLA class I alleles. In self-limiting HEV infection, HEV-specific CD8+ T cells were vigorous, contracted after resolution of infection, and formed functional memory responses. In contrast, in chronic infection, the HEV-specific CD8+ T-cell response was diminished, declined over time, and displayed phenotypic features of exhaustion. However, improved proliferation of HEV-specific CD8+ T cells, increased interferon-γ production and evolution of a memory-like phenotype were observed upon reduction of immunosuppression and/or ribavirin treatment and were associated with viral clearance. In 1 patient, mutational viral escape in a targeted CD8+ T-cell epitope contributed to CD8+ T-cell failure. Chronic HEV infection is associated with HEV-specific CD8+ T-cell exhaustion, indicating that T-cell exhaustion driven by persisting antigen recognition also occurs in severely immunosuppressed hosts. Functional reinvigoration of virus-specific T cells is at least partially possible when antigen is cleared. In a minority of patients, viral escape also contributes to HEV-specific CD8+ T-cell failure and thus needs to be considered in personalized immunotherapeutic approaches. Hepatitis E virus (HEV) infection is usually cleared spontaneously (without treatment) in patients with fully functioning immune systems. In immunosuppressed patients, chronic HEV infection is common and can progress rapidly to cirrhosis and liver failure. Herein, we identified the presence of HEV-specific CD8+ T cells (a specific type of immune cell that can target HEV) in immunosuppressed patients, but we show that these cells do not function properly. This dysfunction appears to play a role in the development of chronic HEV infection in vulnerable patients.

Elimination of coexisting canna yellow mottle virus, bean yellow mosaic virus and cucumber mosaic virus from Canna generalis cv. black knight through in vitro chemotherapy of rhizome explants.

During our previous study, the mixed infection of canna yellow mottle virus (CaYMV), bean yellow mosaic virus (BYMV), and cucumber mosaic virus (CMV) was identified in a Black Knight cultivar of canna exhibiting severe yellow streak and mottling symptoms. Before the development of the virus-free plants, the ability of callogenesis and organogenesis from the ovary, stalk, and rhizome explants was tested on different concentrations and combinations of TDZ, NAA, BAP, and Ads growth regulators. The performance of rhizome explants was above all the explant types and 33.33 ± 1.67 rhizomes (out of 50 placed) showed callus development on ME medium (MS supplemented with 0.8mg/L TDZ and 0.25mg/L NAA) and further on a refined M4 medium (MS supplemented with 4.0mg/L BAP, 1.0mg/L NAA and 50mg/L Ads) produced 4.06 ± 0.16 shoots per explant. The development of virus-free plants was attempted by in vitro chemotherapy using ribavirin. Not only in callogenesis and shoot development but also in the ribavirin treatments, rhizomes developed about 3.78 ± 0.68 shoots per explant on 40mg/L ribavirin in the ME medium. These optimizations suggested that ME medium for callogenesis, M4 medium for shoot development and the treatment of 40mg/L ribavirin for 30days at M4 medium was effective. The elimination of coinfection of all three viruses from rhizome explants of 0.5 cm2 of the Black Knight cultivar was attempted. Consequently, a total of 53.33% of plants free from all three viruses (48 out of the 90 plants developed) were obtained when screened by RT-PCR and PCR for their absence.

Fulminant Transfusion-Associated Hepatitis E Virus Infection Despite Screening, England, 2016-2020.

In England, all blood donations are screened in pools of 24 by nucleic acid test (NAT) for hepatitis E virus (HEV) RNA. During 2016–2020, this screening successfully identified and intercepted 1,727 RNA-positive donations. However, review of previous donations from infected platelet donors identified 9 donations in which HEV RNA detection was missed, of which 2 resulted in confirmed transmission: 1 infection resolved with ribavirin treatment, and 1 proceeded to fatal multiorgan failure within a month from infection. Residual risk calculations predict that over the 5-year study period, HEV RNA detection was missed by minipool NAT in 12–23 platelet and 177–354 whole-blood donations, but transmission risk remains undetermined. Although screening has been able to largely eliminate infectious HEV from the blood supply in England, missed detection of low levels of HEV RNA in donated blood can lead to a severe, even fulminant, infection in recipients and could be prevented by more sensitive screening.

Hepatitis E Virus Infection in Cancer Patients

Hepatitis E virus (HEV) infection in immunocompetent patients can lead to chronic hepatitis and liver failure. However, the burden of HEV infection in cancer patients is largely unknown. We studied the characteristics of HEV infection in patients at a tertiary care cancer center in the United States. This retrospective study included adult cancer patients with HEV infection diagnosed between September 2011 to September 2021. A total of 405 patients were tested for HEV, and 63 (16%) had detectable HEV IgG. Thirty-three patients (52%) were male, 43 were born in America (68%), 46 (73%) were screened for HEV because of pre-existing liver conditions, and 22 (35%) had hematological malignancies. Only 2 patients had detectable HEV RNA. The first patient had myelodysplastic syndrome and underwent allogeneic stem cell transplantation (HSCT). He developed elevated liver enzymes with HEV RNA 14,000 IU/mL (4.2 log IU/mL) 13 months after HSCT. After reducing immunosuppression, his HEV viremia resolved. The second patient had diffuse large B-cell lymphoma and underwent anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. She had elevated liver enzymes with HEV RNA 4,560,000 IU/mL (6.7 log IU/mL) 12 months after CAR T-cell therapy. She developed chronic HEV infection, and ribavirin treatment failed. Now she is being considered for salvage treatment with peginterferon alfa-2a and ribavirin. This study is the first report of chronic HEV infection in patients who received CAR T-cell therapy. HEV infection in cancer patients appears to be at least as common as in the general population. Cancer patients with hematologic malignancies may be at risk for HEV viremia and chronic infection refractory to antiviral treatment.

Observation of the Effect of Ribavirin Treatment on Acute Viral Upper Respiratory Tract Infection

Observation of the Effect of Ribavirin Treatment on Acute Viral Upper Respiratory Tract Infection

Repurposing Dimetridazole and Ribavirin to disarm Pseudomonas aeruginosa virulence by targeting the quorum sensing system.

Pseudomonas aeruginosa relies on its complex cellular regulatory network to produce a series of virulence factors and to cause various acute and chronic infections in a wide range of hosts. Compared with traditional antibiotics which frequently accompany with widespread antibiotic resistance, crippling the virulence system of bacteria is expected to be a promising anti-infective strategy. In this study, Dimetridazole and Ribavirin, which had poor antibacterial activities on P. aeruginosa reference isolate PAO1 in nutrient medium but significantly inhibited the growth of P. aeruginosa PAO1 in M9-adenosine, were selected from 40 marketed compounds with similar core structure (furan, benzofuran, or flavonoids) to the acyl-homoserine lactone signals of P. aeruginosa quorum sensing (QS) system. The production of QS-controlled proteases, pyocyanin, and biofilm formation of P. aeruginosa PAO1 and the clinical isolates were significantly decreased by the presence of Dimetridazole or Ribavirin. Correspondingly, the majority of QS-activated genes in P. aeruginosa, including the key regulatory genes lasR, rhlR, and pqsR and their downstream genes, were significantly inhibited by Ribavirin or Dimetridazole, as determined by RNA-sequencing and quantitative PCR. Furthermore, the susceptibilities of drug-resistant P. aeruginosa isolates to polymyxin B, meropenem, and kanamycin were remarkably promoted by the synergistic application of Dimetridazole or Ribavirin. Finally, the treatment of Ribavirin or Dimetridazole effectively protected Caenorhabditis elegans and mice from P. aeruginosa infection. In conclusion, this study reports the antivirulence potentials of Dimetridazole and Ribavirin on P. aeruginosa and provides structural basis and methodological reference for the development of anti-pseudomonal drugs.

A ribavirin-induced ORF2 single-nucleotide variant produces defective hepatitis E virus particles with immune decoy function

Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and is the leading cause of enterically transmitted viral hepatitis worldwide. Ribavirin (RBV) is currently the only treatment option for many patients; however, cases of treatment failures or posttreatment relapses have been frequently reported. RBV therapy was shown to be associated with an increase in HEV genome heterogeneity and the emergence of distinct HEV variants. In this study, we analyzed the impact of eight patient-derived open reading frame 2 (ORF2) single-nucleotide variants (SNVs), which occurred under RBV treatment, on the replication cycle and pathogenesis of HEV. The parental HEV strain and seven ORF2 variants showed comparable levels of RNA replication in human hepatoma cells and primary human hepatocytes. However, a P79S ORF2 variant demonstrated reduced RNA copy numbers released in the supernatant and an impairment in the production of infectious particles. Biophysical and biochemical characterization revealed that this SNV caused defective, smaller HEV particles with a loss of infectiousness. Furthermore, the P79S variant displayed an altered subcellular distribution of the ORF2 protein and was able to interfere with antibody-mediated neutralization of HEV in a competition assay. In conclusion, an SNV in the HEV ORF2 could be identified that resulted in altered virus particles that were noninfectious invitro and invivo, but could potentially serve as immune decoys. These findings provide insights in understanding the biology of circulating HEV variants and may guide development of personalized antiviral strategies in the future.

A small animal model of chronic hepatitis E infection using immunocompromised rats

Background & AimsHEV variants such as swine genotypes within Paslahepevirus species balayani (HEV-A) and rat HEV (Rocahepevirus ratti; HEV-C1) cause chronic hepatitis E in immunocompromised individuals. There are few reliable and accessible small animal models that accurately reflect chronic HEV infection. We aimed to develop an immunocompromised rat model of chronic hepatitis E infection.MethodsIn this animal model infection study, rats were immunosuppressed with a drug combination (prednisolone, tacrolimus, and mycophenolate mofetil) commonly taken by transplant recipients. Rats were challenged with human- and rat-derived HEV-C1 strains or a human-derived HEV-A strain. Viral load, liver function, liver histology, humoural, and cellular immune responses were monitored.ResultsA high-dose (HD) immunosuppressive regimen consistently prolonged human- and rat-derived HEV-C1 infection in rats (up to 12 weeks post infection) compared with transient infections in low-dose (LD) immunosuppressant-treated and immunocompetent (IC) rats. Mean HEV-C1 viral loads in stool, serum, and liver tissue were higher in HD regimen-treated rats than in LD or IC rats (p <0.05). Alanine aminotransferase elevation was observed in chronically infected rats, which was consistent with histological hepatitis and HEV-C1 antigen expression in liver tissue. None (0/6) of the HD regimen-treated, 5/6 LD regimen-treated, and 6/6 IC rats developed antibodies to HEV-C1 in species-specific immunoblots. Reversal of immunosuppression was associated with clearance of viraemia and restoration of HEV-C1-specific humoural and cellular immune responses in HD regimen-treated rats, mimicking patterns in treated patients with chronic hepatitis E. Viral load suppression was observed with i.p. ribavirin treatment. HD regimen-treated rats remained unsusceptible to HEV-A infection.ConclusionsWe developed a scalable immunosuppressed rat model of chronic hepatitis E that closely mimics this infection phenotype in transplant recipients.Lay summaryConvenient small animal models are required for the study of chronic hepatitis E in humans. We developed an animal model of chronic hepatitis E by suppressing immune responses of rats with drugs commonly taken by humans as organ transplant rejection prophylaxis. This model closely mimicked features of chronic hepatitis E in humans.

Crimean-Congo hemorrhagic fever in Iraq (2018-2022) and an educational review

Background: The first patient with Crimean-Congo hemorrhagic fever was reported in Iraq for the first time on 3rd of September, 1979, and recurrent outbreaks were recorded thereafter with none more patients observed during the next two years. Little is known about the epidemiological state of the disease in Iraq during the previous years. Patients and methods: An overview of the cases of Crimean-Congo hemorrhagic fever registered by the Iraqi Ministry of Health from January, 2018 to May, 2022 is provided. An educational review is presented in the "Discussion". Results: During the year 2018, there were ten cases (including 3 from Diwaniyia province) confirmed by Reverse Transcriptase Polymerase Chain Reaction registered by the Iraqi Ministry of Health, and death occurred in eight of the cases. During the year 2021, the Iraqi Ministry of Health reported the registration of fifteen laboratory confirmed cases of Crimean-Congo hemorrhagic fever during the period from April to November 2021, and 5 deaths occurred. On the 27th of April 2022, the Iraqi Ministry of Health registered 17 cases of laboratory confirmed hemorrhagic fever occurred during the year 2022, and many cases were from ThiQar, and five deaths occurred. Conclusion: 42 cases of laboratory confirmed cases of Crimean-Congo hemorrhagic fever occurred in Iraq during the period from January, 2018 to May, 2022. The disease is still endemic in Iraq and was associated with a high mortality as 18 of the 42 confirmed cases died. Therefore, we are recommending using the available research evidence suggesting the early use of ribavirin in the treatment of patients, and also using ribavirin post-exposure prophylaxis and early ribavirin treatment for workers at medium-to-high risk.

Crimean-Congo hemorrhagic fever in Iraq (2018-2022) and an educational review

Background: The first patient with Crimean-Congo hemorrhagic fever was reported in Iraq for the first time on 3rd of September, 1979, and recurrent outbreaks were recorded thereafter with none more patients observed during the next two years. Little is known about the epidemiological state of the disease in Iraq during the previous years. Patients and methods: An overview of the cases of Crimean-Congo hemorrhagic fever registered by the Iraqi Ministry of Health from January, 2018 to May, 2022 is provided. An educational review is presented in the "Discussion". Results: During the year 2018, there were ten cases (including 3 from Diwaniyia province) confirmed by Reverse Transcriptase Polymerase Chain Reaction registered by the Iraqi Ministry of Health, and death occurred in eight of the cases. During the year 2021, the Iraqi Ministry of Health reported the registration of fifteen laboratory confirmed cases of Crimean-Congo hemorrhagic fever during the period from April to November 2021, and 5 deaths occurred. On the 27th of April 2022, the Iraqi Ministry of Health registered 17 cases of laboratory confirmed hemorrhagic fever occurred during the year 2022, and many cases were from ThiQar, and five deaths occurred. Conclusion: 42 cases of laboratory confirmed cases of Crimean-Congo hemorrhagic fever occurred in Iraq during the period from January, 2018 to May, 2022. The disease is still endemic in Iraq and was associated with a high mortality as 18 of the 42 confirmed cases died. Therefore, we are recommending using the available research evidence suggesting the early use of ribavirin in the treatment of patients, and also using ribavirin post-exposure prophylaxis and early ribavirin treatment for workers at medium-to-high risk.

Long Term Norovirus Infection in a Patient with Severe Common Variable Immunodeficiency.

Norovirus is the most common cause of acute non-bacterial gastroenteritis. Immunocompromised patients can become chronically infected, with or without symptoms. In Europe, common variable immunodeficiency (CVID) is one of the most common inborn errors of immunity. A potentially severe complication is CVID-associated enteropathy, a disorder with similar histopathology to celiac disease. Studies suggest that chronic norovirus infection may be a contributor to CVID enteropathy, and that the antiviral drug ribavirin can be effective against norovirus. Here, a patient with CVID-like disease with combined B- and T-cell deficiency, had chronic norovirus infection and enteropathy. The patient was routinely administered subcutaneous and intravenous immunoglobulin replacement therapy (SCIg and IVIg). The patient was also administered ribavirin for ~7.5 months to clear the infection. Stool samples (collected 2013–2016) and archived paraffin embedded duodenal biopsies were screened for norovirus by qPCR, confirming a chronic infection. Norovirus genotyping was done in 25 stool samples. For evolutionary analysis, the capsid (VP1) and polymerase (RdRp) genes were sequenced in 10 and 12 stool samples, respectively, collected before, during, and after ribavirin treatment. Secretor phenotyping was done in saliva, and serum was analyzed for histo-blood group antigen (HBGA) blocking titers. The chronic norovirus strain formed a unique variant subcluster, with GII.4 Den Haag [P4] variant, circulating around 2009, as the most recent common ancestor. This corresponded to the documented debut of symptoms. The patient was a secretor and had HBGA blocking titers associated with protection in immunocompetent individuals. Several unique amino acid substitutions were detected in immunodominant epitopes of VP1. However, HBGA binding sites were conserved. Ribavirin failed in treating the infection and no clear association between ribavirin-levels and quantity of norovirus shedding was observed. In conclusion, long term infection with norovirus in a patient with severe CVID led to the evolution of a unique norovirus strain with amino acid substitutions in immunodominant epitopes, but conservation within HBGA binding pockets. Regularly administered SCIg, IVIg, and ~7.5-month ribavirin treatment failed to clear the infection.

Lack of Evidence for Ribavirin Treatment of Lassa Fever in Systematic Review of Published and Unpublished Studies1.

Ribavirin has been used widely to treat Lassa fever in West Africa since the 1980s. However, few studies have systematically appraised the evidence for its use. We conducted a systematic review of published and unpublished literature retrieved from electronic databases and gray literature from inception to March 8, 2022. We identified 13 studies of the comparative effectiveness of ribavirin versus no ribavirin treatment on mortality outcomes, including unpublished data from a study in Sierra Leone provided through a US Freedom of Information Act request. Although ribavirin was associated with decreased mortality rates, results of these studies were at critical or serious risk for bias when appraised using the ROBINS-I tool. Important risks for bias related to lack of control for confounders, immortal time bias, and missing outcome data. Robust evidence supporting the use of ribavirin in Lassa fever is lacking. Well-conducted clinical trials to elucidate the effectiveness of ribavirin for Lassa fever are needed.