Duration of Infectious Virus Shedding in Patients with Severe Coronavirus Disease 2019 Who Required Mechanical Ventilation

2021 ◽  
Author(s):  
Toshihito Nomura ◽  
Hiroki Kitagawa ◽  
Keitaro Omori ◽  
Norifumi Shigemoto ◽  
Masaki Kakimoto ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Infectious Virus ◽  
Virus Shedding

scholarly journals Duration of Infectious Virus Shedding in Patients With Severe Coronavirus Disease 2019 Who Required Mechanical Ventilation

2021 ◽  
Author(s):  
Toshihito Nomura ◽  
Hiroki Kitagawa ◽  
Keitaro Omori ◽  
Norifumi Shigemoto ◽  
Masaki Kakimoto ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Symptom Onset ◽  
Infectious Virus ◽  
Quantitative Polymerase Chain Reaction ◽  
University Hospital ◽  
Nasopharyngeal Swab ◽  
Test Results ◽  
Virus Shedding ◽  
Viral Culture ◽  
Respiratory Management

Abstract Approximately 5% of patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 develop severe COVID-19. Severe COVID-19 requires respiratory management with mechanical ventilation and an extended period of treatment. Prolonged infectious virus shedding is a concern in severe COVID-19 cases, but few reports have examined the duration of infectious virus shedding. Therefore, we investigated the duration of infectious virus shedding in patients transferred to Hiroshima University Hospital with severe COVID-19 requiring mechanical ventilation. Nasopharyngeal swab specimens were collected and analyzed using both viral culture and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) tests between December 2020 and February 2021. Of the 23 patients tested, the proportions of those with positive test results at first specimen collection on RT-qPCR and viral culture tests were 95·7% and 30·4%, respectively. All six patients with positive viral culture test results who were followed-up tested negative 24 days after symptom onset but remained positive on RT-qPCR. The longest negative conversion time was observed in a dialysis patient on immunosuppressive drugs. This study indicated that patients with severe COVID-19 remain culture positive for ≥ 10 days after symptom onset. Additionally, immunosuppressed patients with severe COVID-19 could consider isolation for ≥ 20 days.

scholarly journals Duration of infectious virus shedding in patients with severe coronavirus disease 2019 who required mechanical ventilation

2021 ◽  
Author(s):  
Toshihito Nomura ◽  
Hiroki Kitagawa ◽  
Keitaro Omori ◽  
Norifumi Shigemoto ◽  
Masaki Kakimoto ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Infectious Virus ◽  
Virus Shedding

scholarly journals Infectious Norovirus Is Chronically Shed by Immunocompromised Pediatric Hosts

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 619
Author(s):  
Amy Davis ◽  
Valerie Cortez ◽  
Marco Grodzki ◽  
Ronald Dallas ◽  
Jose Ferrolino ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Chronic Infections ◽  
Vitro Assay ◽  
Virus Shedding ◽  
Temporal Aspects ◽  
Male Patients ◽  
Immunocompromised Hosts ◽  
First Time

Noroviruses are a leading cause of gastroenteritis worldwide. Although infections in healthy individuals are self-resolving, immunocompromised individuals are at risk for chronic disease and severe complications. Chronic norovirus infections in immunocompromised hosts are often characterized by long-term virus shedding, but it is unclear whether this shed virus remains infectious. We investigated the prevalence, genetic heterogeneity, and temporal aspects of norovirus infections in 1140 patients treated during a 6-year period at a pediatric research hospital. Additionally, we identified 20 patients with chronic infections lasting 37 to >418 days. Using a new human norovirus in vitro assay, we confirmed the continuous shedding of infectious virus for the first time. Shedding lasted longer in male patients and those with diarrheal symptoms. Prolonged shedding of infectious norovirus in immunocompromised hosts can potentially increase the likelihood of transmission, highlighting the importance of isolation precautions to prevent nosocomial infections.

scholarly journals Age-related susceptibility of ferrets to SARS-CoV-2 infection

2021 ◽  
Author(s):  
Mathias Martins ◽  
Maureen H.V. Fernandes ◽  
Lok R Joshi ◽  
Diego Diel
Keyword(s):  
Respiratory Tract ◽  
Viral Entry ◽  
Infectious Virus ◽  
Health Conditions ◽  
Upper Respiratory Tract ◽  
Infectious Dose ◽  
Virus Shedding ◽  
Age Related ◽  
Upper Respiratory ◽  
Effect Of Age

Susceptibility to SARS-CoV-2 and the outcome of COVID-19 have been linked to underlying health conditions and the age of affected individuals. Here we assessed the effect of age on SARS-CoV-2 infection using a ferret model. For this, young (6-month-old) and aged (18-to-39-month-old) ferrets were inoculated intranasally with various doses of SARS-CoV-2. By using infectious virus shedding in respiratory secretions and seroconversion, we estimated that the infectious dose of SARS-CoV-2 in aged animals is ~32 plaque forming units (PFU) per animal while in young animals it was estimated to be ~100 PFU. We showed that viral replication in the upper respiratory tract and shedding in respiratory secretions is enhanced in aged ferrets when compared to young animals. Similar to observations in humans, this was associated with higher expressions levels of two key viral entry factors - ACE2 and TMPRSS2 - in the upper respiratory tract of aged ferrets.

scholarly journals Daily sampling of early SARS-CoV-2 infection reveals substantial heterogeneity in infectiousness

2021 ◽  
Author(s):  
Ruian Ke ◽  
Pamela P Martinez ◽  
Rebecca L Smith ◽  
Laura L Gibson ◽  
Agha Mirza ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Acute Infection ◽  
Sampling Site ◽  
Virus Shedding ◽  
Individual Level ◽  
Viral Loads ◽  
Infection Dynamics ◽  
Daily Sampling ◽  
Clearance Kinetics ◽  
Longitudinal Sampling

The dynamics of SARS-CoV-2 replication and shedding in humans remain poorly understood. We captured the dynamics of infectious virus and viral RNA shedding during acute infection through daily longitudinal sampling of 60 individuals for up to 14 days. By fitting mechanistic models, we directly estimate viral reproduction and clearance rates, and overall infectiousness for each individual. Significant person-to-person variation in infectious virus shedding suggests that individual-level heterogeneity in viral dynamics contributes to superspreading. Viral genome load often peaked days earlier in saliva than in nasal swabs, indicating strong compartmentalization and suggesting that saliva may serve as a superior sampling site for early detection of infection. Viral loads and clearance kinetics of B.1.1.7 and non-B.1.1.7 viruses were indistinguishable, however B.1.1.7 exhibited a significantly slower pre-peak growth rate in saliva. These results provide a high-resolution portrait of SARS-CoV-2 infection dynamics and implicate individual-level heterogeneity in infectiousness in superspreading.

scholarly journals Virological characteristics of SARS-CoV-2 vaccine breakthrough infections in health care workers

2021 ◽  
Author(s):  
Marc Conrad Shamier ◽  
Alma Tostmann ◽  
Susanne Bogers ◽  
Janet De Wilde ◽  
Jeroen IJpelaar ◽  
...  
Keyword(s):  
Health Care ◽  
Health Care Workers ◽  
Healthcare Workers ◽  
Infectious Virus ◽  
Virus Detection ◽  
Lower Probability ◽  
Rt Pcr ◽  
Virus Shedding ◽  
Care Workers ◽  
Virus Culture

SARS-CoV-2 vaccines are highly effective at preventing COVID-19-related morbidity and mortality. As no vaccine is 100% effective, breakthrough infections are expected to occur. We analyzed the virological characteristics of 161 vaccine breakthrough infections in a population of 24,706 vaccinated healthcare workers (HCWs), using RT-PCR and virus culture. The delta variant (B.1.617.2) was identified in the majority of cases. Despite similar Ct-values, we demonstrate lower probability of infectious virus detection in respiratory samples of vaccinated HCWs with breakthrough infections compared to unvaccinated HCWs with primary SARS-CoV-2 infections. Nevertheless, infectious virus was found in 68.6% of breakthrough infections and Ct-values decreased throughout the first 3 days of illness. We conclude that rare vaccine breakthrough infections occur, but infectious virus shedding is reduced in these cases.

scholarly journals Vaccinia virus: shedding and horizontal transmission in a murine model

2008 ◽  
Vol 89 (12) ◽  
pp. 2986-2991 ◽  
Author(s):  
Jaqueline Maria Siqueira Ferreira ◽  
Jônatas Santos Abrahão ◽  
Betânia Paiva Drumond ◽  
Fernando Meireles Oliveira ◽  
Pedro Augusto Alves ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Infectious Virus ◽  
Natural Infection ◽  
Horizontal Transmission ◽  
Chorioallantoic Membrane ◽  
Virus Shedding ◽  
Natural Hosts ◽  
Relevant Role ◽  
Chicken Chorioallantoic Membrane

Vaccinia virus (VACV) has been associated with several bovine vaccinia outbreaks in Brazil, affecting cattle and humans. There are no available data about VACV environmental circulation or the role of wildlife in the emergence of an outbreak. Since VACV was isolated from rodents in Brazil, we investigated shedding and transmission of VACV strains in mice. The VACV excretion profile was assessed by PCR and chicken chorioallantoic membrane infection, revealing viral DNA and infectious virus in the faeces and urine of intranasally infected mice. Horizontal transmission was assessed by exposure of sentinel mice to wood shavings contaminated with excrement, to mimic a natural infection. Sentinel mice showed orthopoxvirus antibodies, and VACV DNA and infectious virus were detected in their faeces and intestines, even after six rounds of natural transmission. Together, these data suggest that murine excrement could play a relevant role in VACV spread and transmission, perhaps helping to explain how these viruses circulate between their natural hosts.

scholarly journals Repeat COVID-19 Molecular Testing: Correlation with Recovery of Infectious Virus, Molecular Assay Cycle Thresholds, and Analytical Sensitivity

2020 ◽  
Author(s):  
Victoria Gniazdowski ◽  
C. Paul Morris ◽  
Shirlee Wohl ◽  
Thomas Mehoke ◽  
Srividya Ramakrishnan ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Clinical Symptoms ◽  
False Negative ◽  
Digital Pcr ◽  
Viral Rna ◽  
Johns Hopkins Hospital ◽  
Molecular Testing ◽  
Analytical Sensitivity ◽  
Virus Genotype ◽  
Virus Shedding

Repeat molecular testing for SARS-CoV-2 may result in scenarios including multiple positive results, positive test results after negative tests, and repeated false negative results in symptomatic individuals. Consecutively collected specimens from a retrospective cohort of COVID-19 patients at the Johns Hopkins Hospital were assessed for RNA and infectious virus shedding. Whole genome sequencing confirmed the virus genotype in patients with prolonged viral RNA shedding and droplet digital PCR (ddPCR) was used to assess the rate of false negative standard of care PCR results. Recovery of infectious virus was associated with Ct values of 18.8 ± 3.4. Prolonged viral RNA shedding was associated with recovery of infectious virus in specimens collected up to 20 days after the first positive result in patients who were symptomatic at the time of specimen collection. The use of Ct values and clinical symptoms provides a more accurate assessment of the potential for infectious virus shedding.

scholarly journals Longitudinal analysis of SARS-CoV-2 vaccine breakthrough infections reveal limited infectious virus shedding and restricted tissue distribution

2021 ◽  
Author(s):  
Ruian Ke ◽  
Pamela Martinez ◽  
Rebecca Lee Smith ◽  
Laura Gibson ◽  
Chad Achenbach ◽  
...  
Keyword(s):  
Tissue Distribution ◽  
Longitudinal Analysis ◽  
Infectious Virus ◽  
Symptom Duration ◽  
Viral Dynamics ◽  
Virus Shedding ◽  
Transmission Potential ◽  
Small Cohort ◽  
Longitudinal Sampling ◽  
Shed Light

The global effort to vaccinate people against SARS-CoV-2 in the midst of an ongoing pandemic has raised questions about the nature of vaccine breakthrough infections and the potential for vaccinated individuals to transmit the virus. These questions have become even more urgent as new variants of concern with enhanced transmissibility, such as Delta, continue to emerge. To shed light on how vaccine breakthrough infections compare with infections in immunologically naive individuals, we examined viral dynamics and infectious virus shedding through daily longitudinal sampling in a small cohort of adults infected with SARS-CoV-2 at varying stages of vaccination. The durations of both infectious virus shedding and symptoms were significantly reduced in vaccinated individuals compared with unvaccinated individuals. We also observed that breakthrough infections are associated with strong tissue compartmentalization and are only detectable in saliva in some cases. These data indicate that vaccination shortens the duration of time of high transmission potential, minimizes symptom duration, and may restrict tissue dissemination.

scholarly journals Infectious viral load in unvaccinated and vaccinated patients infected with SARS-CoV-2 WT, Delta and Omicron

2022 ◽  
Author(s):  
Olha Puhach ◽  
Kenneth Adea ◽  
Nicolas Hulo ◽  
Pascale Sattonnet-Roche ◽  
Camille Genecand ◽  
...  
Keyword(s):  
Viral Load ◽  
National Science Foundation ◽  
Infectious Virus ◽  
Virus Isolation ◽  
Transmission Risk ◽  
Swiss National Science Foundation ◽  
Virus Shedding ◽  
Cell Culture Isolation ◽  
Rna Genome ◽  
Lower Transmission

Abstract Background Viral load (VL) is one determinant of secondary transmission of SARS-CoV-2. Emergence of variants of concerns (VOC) Alpha and Delta was ascribed, at least partly, to higher VL. Furthermore, with parts of the population vaccinated, knowledge on VL in vaccine breakthrough infections is crucial. As RNA VL is only a weak proxy for infectiousness, studies on infectious virus presence by cell culture isolation are of importance. Methods We assessed nasopharyngeal swabs of COVID-19 patients for quantitative infectious viral titres (IVT) by focus-forming assay and compared to overall virus isolation success and RNA genome copies. We assessed infectious viral titres during the first 5 symptomatic days in a total of 384 patients: unvaccinated individuals infected with pre-VOC SARS-CoV-2 (n= 118) or Delta (n= 127) and vaccine breakthrough infections with Delta (n= 121) or Omicron (n=18). Findings Correlation between RNA copy number and IVT was low for all groups. No correlation between IVTs and age or sex was seen. We observed higher RNA genome copies in pre-VOC SARS-CoV-2 compared to Delta, but significantly higher IVTs in Delta infected individuals. In vaccinated vs. unvaccinated Delta infected individuals, RNA genome copies were comparable but vaccinated individuals have significantly lower IVTs, and cleared virus faster. Vaccinated individuals with Omicron infection had comparable IVTs to Delta breakthrough infections. Interpretation Quantitative IVTs can give detailed insights into virus shedding kinetics. Vaccination was associated with lower infectious titres and faster clearance for Delta, showing that vaccination would also lower transmission risk. Omicron vaccine breakthrough infections did not show elevated IVTs compared to Delta, suggesting that other mechanisms than increase VL contribute to the high infectiousness of Omicron. Funding This work was supported by the Swiss National Science Foundation 196644, 196383, NRP (National Research Program) 78 Covid-19 Grant 198412, the Fondation Ancrage Bienfaisance du Groupe Pictet and the Fondation Privée des Hôpitaux Universitaires de Genève.

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