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Background Licensed vaccines against SARS-CoV-2 effectively protect against severe disease, but display incomplete protection against virus transmission. Mucosal vaccines providing immune responses in the upper airways are one strategy to protect against transmission. Methods We administered Spike HexaPro trimer formulated in a cationic liposomal adjuvant as a parenteral (subcutaneous – s.c.) prime - intranasal boost regimen to elicit airway mucosal immune responses and evaluated this in a Syrian hamster model of virus transmission. Findings Parenteral prime - intranasal boost elicited high-magnitude serum neutralizing antibody responses and IgA responses in the upper respiratory tract. The vaccine strategy protected against virus in the lower airways and lung pathology, but virus could still be detected in the upper airways. Despite this, the parenteral prime - intranasal booster vaccine effectively protected against onward SARS-CoV-2 transmission. Interpretation This study suggests that parenteral-prime mucosal boost is an effective strategy for protecting against SARS-CoV-2 infection and highlights that protection against virus transmission may be obtained despite incomplete clearance of virus from the upper respiratory tract. It should be noted that protection against onward transmission was not compared to standard parenteral prime-boost, which should be a focus for future studies. Funding This work was primarily supported by the European Union Horizon 2020 research and innovation program under grant agreement no. 101003653.

Background and Aims: Lack of tractable immunocompetent animal models amenable to robust experimental challenge impedes vaccine efforts for HCV. Infection with rodent hepacivirus from Rattus norvegicus (RHV-rn1) in rats shares HCV-defining characteristics, including liver tropism, chronicity, and pathology. RHV in vitro cultivation would facilitate genetic studies on particle production, host factor interactions, and evaluation of antibody neutralization guiding HCV vaccine approaches. Approach and Results: We report an infectious reverse genetic cell culture system for RHV-rn1 using highly permissive rat hepatoma cells and adaptive mutations in the E2, NS4B, and NS5A viral proteins. Cell culture–derived RHV-rn1 particles (RHVcc) share hallmark biophysical characteristics of HCV and are infectious in mice and rats. Culture adaptive mutations attenuated RHVcc in immunocompetent rats, and the mutations reverted following prolonged infection, but not in severe combined immunodeficiency (SCID) mice, suggesting that adaptive immune pressure is a primary driver of reversion. Accordingly, sera from RHVcc-infected SCID mice or the early acute phase of immunocompetent mice and rats were infectious in culture. We further established an in vitro RHVcc neutralization assay, and observed neutralizing activity of rat sera specifically from the chronic phase of infection. Finally, we found that scavenger receptor class B type I promoted RHV-rn1 entry in vitro and in vivo. Conclusions: The RHV-rn1 infectious cell culture system enables studies of humoral immune responses against hepacivirus infection. Moreover, recapitulation of the entire RHV-rn1 infectious cycle in cell culture will facilitate reverse genetic studies and the exploration of tropism and virus–host interactions.

Introduction: Valid and reliable methods for diagnosing depression are essential. The present study aimed to test the performance of a new diagnostic interview for depression focusing on the core symptoms of depression. Method: We developed a diagnostic interview for depression: the CORE Diagnostic Interview, CORE-DI, which assesses each of the core features of depression on the four dimensions: quality, reactivity, globality, and fluctuations over time. The diagnostic performance of this interview was tested in a clinical study including 83 individuals presenting with various depressive symptoms, who were interviewed independently (1) by means of the CORE-DI and the Mini-International Neuropsychiatric Interview (M.I.N.I.), and (2) by highly skilled specialists in depression representing gold standard diagnoses. Results: We compared the outcome of the CORE-DI, the M.I.N.I., and the diagnosis made by clinicians, respectively, versus the gold standard diagnosis, using diagnostic efficiency statistics. The CORE-DI diagnosed depression with a high specificity (0.91, 95% CI: 0.85-0.97, for International Classification of Diseases [ICD]-10 criteria and 0.88, 95% CI: 0.81-0.95, for Diagnostic and Statistical Manual of Mental Disorders [DSM-5] criteria) compared to both M.I.N.I (specificity 0.44, 95% CI: 0.33-0.55) and clinical diagnoses (specificity 0.76, 95% CI: 0.67-0.85). The sensitivity of the CORE-DI was 0.61 (95% CI: 0.55-0.72) for ICD-10 criteria and 0.67 (95% CI: 0.57-0.77) for DSM-5 criteria. Discussion/Conclusion: The CORE-DI increased the specificity of the depression diagnosis substantially compared to clinical diagnoses and the diagnoses obtained by M.I.N.I. The results point to the usefulness of an elaborated and systematic assessment of the core symptoms in the examination of patients with depressive symptoms and thereby indicate a way for further development of specific diagnostic tools for depression in both clinical and research settings. However, it s

Hepatitis C virus (HCV) infections pose a major public health burden due to high chronicity rates and associated morbidity and mortality. A vaccine protecting against chronic infection is not available but would be important for global control of HCV infections. In this study, cell culture‐based HCV production was established in a packed‐bed bioreactor (CelCradle™) aiming to further the development of an inactivated whole virus vaccine and to facilitate virological and immunological studies requiring large quantities of virus particles. HCV was produced in human hepatoma‐derived Huh7.5 cells maintained in serum‐free medium on days of virus harvesting. Highest virus yields were obtained when the culture was maintained with two medium exchanges per day. However, increasing the total number of cells in the culture vessel negatively impacted infectivity titers. Peak infectivity titers of up to 7.2 log10 focus forming units (FFU)/mL, accumulated virus yields of up to 5.9 × 1010 FFU, and a cell specific virus yield of up to 41 FFU/cell were obtained from one CelCradle™. CelCradle™‐derived and T flask‐derived virus had similar characteristics regarding neutralization sensitivity and buoyant density. This packed‐bed tide‐motion system is available with larger vessels and may thus be a promising platform for large‐scale HCV production.

The COVID-19 pandemic continues to threaten healthcare systems worldwide due to the limited access to vaccines, suboptimal treatment options, and the continuous emergence of new and more transmissible SARS-CoV-2 variants. Reverse-genetics studies of viral genes and mutations have proven highly valuable in advancing basic virus research, leading to the development of therapeutics. We developed a functional and highly versatile full-length SARS-CoV-2 infectious system by cloning the sequence of a COVID-19 associated virus isolate (DK-AHH1) into a bacterial artificial chromosome (BAC). Viruses recovered after RNA-transfection of in vitro transcripts into Vero E6 cells showed growth kinetics and remdesivir susceptibility similar to the DK-AHH1 virus isolate. Insertion of reporter genes, green fluorescent protein, and nanoluciferase into the ORF7 genomic region led to high levels of reporter activity, which facilitated high throughput treatment experiments. We found that putative coronavirus remdesivir resistance-associated substitutions F480L and V570L—and naturally found polymorphisms A97V, P323L, and N491S, all in nsp12—did not decrease SARS-CoV-2 susceptibility to remdesivir. A nanoluciferase reporter clone with deletion of spike (S), envelope (E), and membrane (M) proteins exhibited high levels of transient replication, was inhibited by remdesivir, and therefore could function as an efficient non-infectious subgenomic replicon system. The developed SARS-CoV-2 reverse-genetics systems, including recombinants to modify infectious viruses and non-infectious subgenomic replicons with autonomous genomic RNA replication, will permit high-throughput cell culture studies—providing fundamental understanding of basic biology of this coronavirus. We have proven the utility of the systems in rapidly introducing mutations in nsp12 and studying their effect on the efficacy of remdesivir, which is used worldwide for the treatment of COVID-19. Our system provides a platform to e

With increasing numbers of vaccine-breakthrough infections worldwide, assessing the immunogenicity of vaccinated health-care workers that are frequently exposed to SARS-CoV-2-infected individuals is important. In this study, neutralization titers against SARS-CoV-2 were assessed one month after completed prime-boost vaccine regimens in health-care workers vaccinated with either mRNA–mRNA (Comirnaty®, BioNTech-Pfzier, Mainz, Germany/New York, NY, USA, n = 98) or vector-based (Vaxzevria®, Oxford-AstraZeneca, Cambridge, UK) followed by mRNA-based (Comirnaty® or Spikevax®, Moderna, Cambridge, MA, USA) vaccines (n = 16). Vaccine-induced neutralization titers were compared to time-matched, unvaccinated individuals that were infected with SARS-CoV-2 and presented with mild symptoms (n = 38). Significantly higher neutralizing titers were found in both the mRNA–mRNA (ID50: 2525, IQR: 1667–4313) and vector–mRNA (ID50: 4978, IQR: 3364–7508) prime-boost vaccine regimens when compared to SARS-CoV-2 infection (ID50: 401, IQR: 271–792) (p < 0.0001). However, infection with SARS-CoV-2 induced higher titers when compared to a single dose of Vaxzevria® (p = 0.0072). Between mRNA–mRNA and vector– mRNA prime-boost regimens, the vector–mRNA vaccine regimen induced higher neutralization titers (p = 0.0054). Demographically, both age and time between vaccination doses were associated with vaccine-induced neutralization titers (p = 0.02 and p = 0.03, respectively). This warrants further investigation into the optimal time to administer booster vaccination for optimized induction of neutralizing responses. Although anecdotal (n = 3), those with exposure to SARS-CoV-2, either before or after vaccination, demonstrated superior neutralizing titers, which is suggestive of further boosting through viral exposure.