Passive Immunotherapies Protect WRvFire and IHD-J-Luc Vaccinia Virus-Infected Mice from Lethality by Reducing Viral Loads in the Upper Respiratory Tract and Internal Organs

Abstract Differential kinetics of RNA loads and infectious viral levels in the upper respiratory tract between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations that may guide clinical management, infection control measures and occupational health decisions. In the present investigation, 496 (2.5%) of 17,911 French adult outpatients were positive for an upper respiratory tract SARS-CoV-2 RNA detection by a quantitative RT-PCR assay, of which 180 (36.3%) were COVID-19 asymptomatic. Of these adult asymptomatic viral shedders, 84.4% had mean to high RNA viral loads (Ct values<30) which median value was significantly higher than that observed in symptomatic subjects (P=0.029), and 50.6% were positive by cell culture assays of their upper respiratory tract specimens. Our findings indicate that COVID-19 asymptomatic adult outpatients are significant viable SARS-CoV-2 shedders in their upper respiratory tract playing a major potential role as SARS-CoV-2 transmitters in various epidemiological transmission chains, promoting COVID-19 resurgence in populations.

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Reduced Pathogenicity of the SARS-CoV-2 Omicron Variant in Hamsters

10.1101/2022.01.02.474743 ◽

2022 ◽

Author(s):

Katherine McMahan ◽

Victoria Giffin ◽

Lisa Tostanoski ◽

Benjamin Chung ◽

Mazuba Siamatu ◽

...

Keyword(s):

Weight Loss ◽

Respiratory Tract ◽

Lung Parenchyma ◽

Clinical Disease ◽

Upper Respiratory Tract ◽

Viral Loads ◽

Syrian Golden Hamsters ◽

The World ◽

Pulmonary Pathology ◽

Upper Respiratory

The SARS-CoV-2 Omicron (B.1.1.529) variant has proven highly transmissible and has outcompeted the Delta variant in many regions of the world. Early reports have also suggested that Omicron may result in less severe clinical disease in humans. Here we show that Omicron is less pathogenic than prior SARS-CoV-2 variants in Syrian golden hamsters. Infection of hamsters with the SARS-CoV-2 WA1/2020, Alpha, Beta, or Delta strains led to 4-10% weight loss by day 4 and 10-17% weight loss by day 6, as expected. In contrast, infection of hamsters with two different Omicron challenge stocks did not result in any detectable weight loss, even at high challenge doses. Omicron infection still led to substantial viral replication in both the upper and lower respiratory tracts and pulmonary pathology, but with a trend towards higher viral loads in nasal turbinates and lower viral loads in lung parenchyma compared with WA1/2020 infection. These data suggest that the SARS-CoV-2 Omicron variant may result in more robust upper respiratory tract infection but less severe lower respiratory tract clinical disease compared with prior SARS-CoV-2 variants.

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Induction of interferon response by high viral loads at early stage infection may protect against severe outcomes in COVID-19 patients

Scientific Reports ◽

10.1038/s41598-021-95197-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Eric C. Rouchka ◽

Julia H. Chariker ◽

Brian Alejandro ◽

Robert S. Adcock ◽

Richa Singhal ◽

...

Keyword(s):

Gene Expression ◽

Viral Load ◽

Respiratory Tract ◽

Disease Severity ◽

Critical Factor ◽

Interferon Response ◽

Upper Respiratory Tract ◽

Viral Loads ◽

Antiviral Responses ◽

Upper Respiratory

AbstractKey elements for viral pathogenesis include viral strains, viral load, co-infection, and host responses. Several studies analyzing these factors in the function of disease severity of have been published; however, no studies have shown how all of these factors interplay within a defined cohort. To address this important question, we sought to understand how these four key components interplay in a cohort of COVID-19 patients. We determined the viral loads and gene expression using high throughput sequencing and various virological methods. We found that viral loads in the upper respiratory tract in COVID-19 patients at an early phase of infection vary widely. While the majority of nasopharyngeal (NP) samples have a viral load lower than the limit of detection of infectious viruses, there are samples with an extraordinary amount of SARS-CoV-2 RNA and a high viral titer. No specific viral factors were identified that are associated with high viral loads. Host gene expression analysis showed that viral loads were strongly correlated with cellular antiviral responses. Interestingly, however, COVID-19 patients who experience mild symptoms have a higher viral load than those with severe complications, indicating that naso-pharyngeal viral load may not be a key factor of the clinical outcomes of COVID-19. The metagenomics analysis revealed that the microflora in the upper respiratory tract of COVID-19 patients with high viral loads were dominated by SARS-CoV-2, with a high degree of dysbiosis. Finally, we found a strong inverse correlation between upregulation of interferon responses and disease severity. Overall our study suggests that a high viral load in the upper respiratory tract may not be a critical factor for severe symptoms; rather, dampened antiviral responses may be a critical factor for a severe outcome from the infection.

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Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models

Science Translational Medicine ◽

10.1126/scitranslmed.abh0755 ◽

2021 ◽

pp. eabh0755

Author(s):

Neeltje van Doremalen ◽

Jyothi N. Purushotham ◽

Jonathan E. Schulz ◽

Myndi G. Holbrook ◽

Trenton Bushmaker ◽

...

Keyword(s):

Respiratory Tract ◽

Direct Contact ◽

Infectious Virus ◽

Rhesus Macaques ◽

Upper Respiratory Tract ◽

Preclinical Models ◽

Viral Loads ◽

Viral Shedding ◽

Nasal Swabs ◽

Upper Respiratory

ChAdOx1 nCoV-19/AZD1222 is an approved adenovirus-based vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently being deployed globally. Previous studies in rhesus macaques revealed that intramuscular vaccination with ChAdOx1 nCoV-19/AZD1222 provided protection against pneumonia but did not reduce shedding of SARS-CoV-2 from the upper respiratory tract. Here, we investigated whether intranasally administered ChAdOx1 nCoV-19 reduces detection of virus in nasal swabs after challenging vaccinated macaques and hamsters with SARS-CoV-2 carrying a D614G mutation in the spike protein. Viral loads in swabs obtained from intranasally vaccinated hamsters were decreased compared to control hamsters, and no viral RNA or infectious virus was found in lung tissue after a direct challenge or after direct contact with infected hamsters. Intranasal vaccination of rhesus macaques resulted in reduced virus concentrations in nasal swabs and a reduction in viral loads in bronchoalveolar lavage and lower respiratory tract tissue. Intranasal vaccination with ChAdOx1 nCoV-19/AZD1222 reduced virus concentrations in nasal swabs in two different SARS-CoV-2 animal models, warranting further investigation as a potential vaccination route for COVID-19 vaccines.

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Viral load in upper respiratory tract of COVID-19 patients detected by digital PCR

10.21203/rs.3.rs-29834/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Jiankang Zhao ◽

Haibo Li ◽

Hui Li ◽

Qiaoling Wu ◽

Ke Wu ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Digital Pcr ◽

Upper Respiratory Tract ◽

Rt Pcr ◽

Lung Lesions ◽

Viral Loads ◽

Ct Value ◽

Upper Respiratory ◽

Close Contacts

Abstract Background: Upper respiratory tract specimens are widely applicable for the diagnosis of COVID-19. To date, no study has analyzed the actual viral loads in upper respiratory tract and its relationship with the severity of lung lesions, Ct value of RT-PCR and transmission capacity in COVID-19 patients.Methods: We retrospectively enrolled nine COVID-19 patients. Clinical data and close contacts of these patients were investigated. Respiratory samples were tested for SARS-CoV-2 with both normal RT-PCR and droplet digital PCR.Results: All the COVID-19 patients complicated with pneumonia. Viral loads in nasopharyngeal swabs were accurately quantified, and they had no direct correspondence with the severity of lung lesions. The Cycle Threshold (Ct) value of RT-PCR was approximately consistent with the absolute quantification of digital PCR. The spearman correlation coefficient between them was -0.952 with P value < 0.001. Close contacts of patients with very low viral load or no detected virus were not infected.Conclusions: Viral loads in nasopharyngeal swabs, could not predict the severity of lung lesions revealed by CT in COVID-19 patients. The infectious capacity of patients with low or absent viral load in upper respiratory tract was relatively weak, and wearing mask might be helpful for lower its spread.

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SARS-CoV-2 Infections in mRNA Vaccinated Individuals are Biased for Viruses Encoding Spike E484K and Associated with Reduced Infectious Virus Loads that Correlate with Respiratory Antiviral IgG levels.

10.1101/2021.07.05.21259105 ◽

2021 ◽

Author(s):

Heba H Mostafa ◽

chun Huai Luo ◽

C. Paul Morris ◽

Maggie Li ◽

Nicholas J Swanson ◽

...

Keyword(s):

Cell Culture ◽

Respiratory Tract ◽

Large Scale ◽

Infectious Virus ◽

Time Frame ◽

Molecular Testing ◽

Upper Respiratory Tract ◽

Symptomatic Infection ◽

Viral Loads ◽

Upper Respiratory

Abstract Introduction COVID-19 large scale immunization in the US has been associated with infrequent breakthrough positive molecular testing. Whether a positive test is associated with a high viral RNA load, specific viral variant, recovery of infectious virus, or symptomatic infection is largely not known. Methods In this study, we identified 133 SARS-CoV-2 positive patients who had received two doses of either Pfizer-BioNTech (BNT162b2) or Moderna (mRNA-1273) vaccines, the 2nd of which was received between January and April of 2021. The positive samples were collected between January and May of 2021 with a time that extended from 2 to 100 days after the second dose. Samples were sequenced to characterize the whole genome and Spike protein changes and cycle thresholds that reflect viral loads were determined using a single molecular assay. Local SARS-CoV-2 IgG antibodies were examined using ELISA and specimens were grown on cell culture to assess the recovery of infectious virus as compared to a control unvaccinated cohort from a matched time frame. Results Of 133 specimens, 24 failed sequencing and yielded a negative or very low viral load on the repeat PCR. Of 109 specimens that were used for further genome analysis, 68 (62.4%) were from symptomatic infections, 11 (10.1%) were admitted for COVID-19, and 2 (1.8%) required ICU admission with no associated mortality. The predominant virus variant was the alpha (B.1.1.7), however a significant association between lineage B.1.526 and amino acid change S: E484K with positives after vaccination was noted when genomes were compared to a large control cohort from a matched time frame. A significant reduction of the recovery of infectious virus on cell culture as well as delayed time to the first appearance of cytopathic effect was accompanied by an increase in local IgG levels in respiratory samples of vaccinated individuals but upper respiratory tract IgG levels were not different between symptomatic or asymptomatic infections. Conclusions Vaccination reduces the recovery of infectious virus in breakthrough infections accompanied by an increase in upper respiratory tract local immune responses.

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Longitudinal Analysis of Inflammatory Response to SARS-CoV-2 in the Upper Respiratory Tract Reveals an Association with Viral Load, Independent of Symptoms

Journal of Clinical Immunology ◽

10.1007/s10875-021-01134-z ◽

2021 ◽

Author(s):

Diem-Lan Vu ◽

Paola Martinez-Murillo ◽

Fiona Pigny ◽

Maria Vono ◽

Benjamin Meyer ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Upper Respiratory Tract ◽

University Hospitals ◽

Viral Loads ◽

Gm Csf ◽

Cytokine Levels ◽

Control Virus ◽

Upper Respiratory ◽

Local Recruitment

Abstract Background SARS-CoV-2 infection leads to high viral loads in the upper respiratory tract that may be determinant in virus dissemination. The extent of intranasal antiviral response in relation to symptoms is unknown. Understanding how local innate responses control virus is key in the development of therapeutic approaches. Methods SARS-CoV-2-infected patients were enrolled in an observational study conducted at the Geneva University Hospitals, Switzerland, investigating virological and immunological characteristics. Nasal wash and serum specimens from a subset of patients were collected to measure viral load, IgA specific for the S1 domain of the spike protein, and a cytokine panel at different time points after infection; cytokine levels were analyzed in relation to symptoms. Results Samples from 13 SARS-CoV-2-infected patients and six controls were analyzed. We found an increase in CXCL10 and IL-6, whose levels remained elevated for up to 3 weeks after symptom onset. SARS-CoV-2 infection also induced CCL2 and GM-CSF, suggesting local recruitment and activation of myeloid cells. Local cytokine levels correlated with viral load but not with serum cytokine levels, nor with specific symptoms, including anosmia. Some patients had S1-specific IgA in the nasal cavity while almost none had IgG. Conclusion The nasal epithelium is an active site of cytokine response against SARS-CoV-2 that can last more than 2 weeks; in this mild COVID-19 cohort, anosmia was not associated with increases in any locally produced cytokines.

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Intranasal Vaccination with a Lentiviral Vector Strongly Protects against SARS-CoV-2 in Mouse and Golden Hamster Preclinical Models

10.1101/2020.07.21.214049 ◽

2020 ◽

Cited By ~ 1

Author(s):

Min-Wen Ku ◽

Maryline Bourgine ◽

Pierre Authié ◽

Jodie Lopez ◽

Kirill Nemirov ◽

...

Keyword(s):

Immune Response ◽

Respiratory Tract ◽

Neutralizing Antibodies ◽

Vaccine Candidate ◽

Lentiviral Vector ◽

Upper Respiratory Tract ◽

Partial Protection ◽

Viral Loads ◽

Powerful Approach ◽

Upper Respiratory

SummaryTo develop a vaccine candidate against COVID-19, we generated a Lentiviral Vector (LV), eliciting neutralizing antibodies against the Spike glycoprotein of SARS-CoV-2. Systemic vaccination by this vector in mice, in which the expression of the SARS-CoV-2 receptor hACE2 has been induced by transduction of respiratory tract cells by an adenoviral vector, conferred only partial protection, despite an intense serum neutralizing activity. However, targeting the immune response to the respiratory tract through an intranasal boost with this LV resulted in > 3 log10 decrease in the lung viral loads and avoided local inflammation. Moreover, both integrative and non-integrative LV platforms displayed a strong vaccine efficacy and inhibited lung deleterious injury in golden hamsters, which are naturally permissive to SARS-CoV-2 replication and restitute the human COVID-19 physiopathology. Our results provide evidence of marked prophylactic effects of the LV-based vaccination against SARS-CoV-2 and designate the intranasal immunization as a powerful approach against COVID-19.HighlightsA lentiviral vector encoding for Spike predicts a promising COVID-19 vaccineTargeting the immune response to the upper respiratory tract is key to protectionIntranasal vaccination induces protective mucosal immunity against SARS-CoV-2Lung anti-Spike IgA responses correlate with protection and reduced inflammation

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Association between upper respiratory tract viral load, comorbidities, disease severity and outcome of patients with SARS-CoV-2 infection

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa804 ◽

2021 ◽

Author(s):

Helena C Maltezou ◽

Vasilios Raftopoulos ◽

Rengina Vorou ◽

Kalliopi Papadima ◽

Kassiani Mellou ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Disease Severity ◽

High Viral Load ◽

P Value ◽

Upper Respiratory Tract ◽

Limited Information ◽

Symptomatic Disease ◽

Viral Loads ◽

Upper Respiratory

Abstract Background There is limited information on the association between upper respiratory tract (URT) viral loads, host factors, and disease severity in SARS-CoV-2 infected patients. Methods We studied 1,122 patients (mean age: 46 years) diagnosed by PCR. URT viral load, measured by PCR cycle threshold, was categorized as high, moderate or low. Results There were 336 (29.9%) patients with comorbidities; 309 patients (27.5%) had high, 316 (28.2%) moderate, and 497 (44.3%) low viral load. In univariate analyses, compared to patients with moderate or low viral load, patients with high viral load were older, had more often comorbidities, developed symptomatic disease, were intubated and died; in addition, patients with high viral load had longer stay in intensive care unit and longer intubation compared to patients with low viral load (p-values <0.05 for all). Patients with chronic cardiovascular disease, hypertension, chronic pulmonary disease, immunosuppression, obesity and chronic neurological disease had more often high viral load (p-value<0.05 for all). Multivariate analysis found that a high viral load was associated with COVID-19. The level of viral load was not associated with any other outcome. Conclusions URT viral load could be used to identify patients at higher risk for morbidity or severe outcome.

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Post-slaughter changes in rabbit carcasses in Poland between 2010 and 2018

Medycyna Weterynaryjna ◽

10.21521/mw.6294 ◽

2019 ◽

Vol 75 (10) ◽

pp. 6294-2019

Author(s):

ŁUKASZ DROZD ◽

WALDEMAR PASZKIEWICZ ◽

RENATA PYZ-ŁUKASIK ◽

MONIKA ZIOMEK ◽

KRZYSZTOF SZKUCIK

Keyword(s):

Infectious Diseases ◽

Respiratory Tract ◽

Fold Increase ◽

Parasitic Diseases ◽

Upper Respiratory Tract ◽

Pathological Changes ◽

Respiratory Tract Disease ◽

Internal Organs ◽

Upper Respiratory ◽

Tract Disease

The aim of the study was to analyze the results of sanitary and veterinary examinations of rabbits carried out by the Veterinary Inspectorate in slaughterhouses in Poland in 2010-2018. In this period, 8,980,660 rabbits were examined. Lesions and quality deviations were found in 42,779 carcasses, i.e. 0.48% of all carcasses examined. The most frequent causes of the rejection of the carcasses and internal organs of the rabbits examined were sepsis and pyaemia (36,369 cases), followed by excessive emaciation (1,686 cases), upper respiratory tract disease (1,655 cases), other causes not specified by name (1,438 cases), and coccidiosis (1,318 cases). Abnormal exsanguination (303), parasitic diseases other than coccidiosis (67), infectious diseases (14), and leukemia (2) were much less often the cause of rejection. During the period analyzed, there was a decrease in the number of cases of coccidiosis (except in 2017) and other parasitic diseases, but there was a several-fold increase in the occurrence of sepsis and pyaemia (in the years 2015-2018). Compared with the results of veterinary and sanitary examinations of rabbits in 2000-2010, there was an increase in the number of rabbits slaughtered and a reduction in the percentage of carcasses with pathological changes and carcasses deemed unfit for consumption. In the years 2010-2018, there was also an increase in the number of cases of sepsis and pyaemia and a significant decrease in the percentage of parasitic diseases (mainly coccidiosis).

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