scholarly journals Increased aerosol transmission for B.1.1.7 (alpha variant) over lineage A variant of SARS-CoV-2

2021 ◽  
Author(s):  
Julia Port ◽  
Kwe Claude Yinda ◽  
Victoria Avanzato ◽  
Jonathan Schulz ◽  
Myndi Holbrook ◽  
...  
Keyword(s):  
Transmission Efficiency ◽  
Mitigation Strategies ◽  
Transmission Route ◽  
Airborne Transmission ◽  
Experimental Proof ◽  
Infectious Dose ◽  
Successful Transmission ◽  
Transmission Potential ◽  
Novel Variants ◽  
Alpha Variant

Airborne transmission, a term combining both large droplet and aerosol transmission, is thought to be the main transmission route of SARS-CoV-2. Here we investigated the relative efficiency of aerosol transmission of two variants of SARS-CoV-2, B.1.1.7 (alpha) and lineage A, in the Syrian hamster. A novel transmission caging setup was designed and validated, which allowed the assessment of transmission efficiency at various distances. At 2 meters distance, only particles <5 micrometer traversed between cages. In this setup, aerosol transmission was confirmed in 8 out of 8 (N = 4 for each variant) sentinels after 24 hours of exposure as demonstrated by respiratory shedding and seroconversion. Successful transmission occurred even when exposure time was limited to one hour, highlighting the efficiency of this transmission route. Interestingly, the B.1.1.7 variant outcompeted the lineage A variant in an airborne transmission chain after mixed infection of donors. Combined, this data indicates that the infectious dose of B.1.1.7 required for successful transmission may be lower than that of lineage A virus. The experimental proof for true aerosol transmission and the increase in the aerosol transmission potential of B.1.1.7 underscore the continuous need for assessment of novel variants and the development or preemptive transmission mitigation strategies.

scholarly journals Increased aerosol transmission for B.1.1.7 (alpha variant) over lineage A variant of SARS-CoV-2

2021 ◽  
Author(s):  
Julia Port ◽  
Claude Kwe Yinda ◽  
Victoria Avanzato ◽  
Jonathan Schulz ◽  
Myndi Holbrook ◽  
...  
Keyword(s):  
Transmission Efficiency ◽  
Mitigation Strategies ◽  
Transmission Route ◽  
Airborne Transmission ◽  
Experimental Proof ◽  
Infectious Dose ◽  
Successful Transmission ◽  
Transmission Potential ◽  
Novel Variants ◽  
Alpha Variant

Abstract Airborne transmission, a term combining both large droplet and aerosol transmission, is thought to be the main transmission route of SARS-CoV-2. Here we investigated the relative efficiency of aerosol transmission of two variants of SARS-CoV-2, B.1.1.7 (alpha) and lineage A, in the Syrian hamster. A novel transmission caging setup was designed and validated, which allowed the assessment of transmission efficiency at various distances. At 2 meters distance, only particles <5 µm traversed between cages. In this setup, aerosol transmission was confirmed in 8 out of 8 (N = 4 for each variant) sentinels after 24 hours of exposure as demonstrated by respiratory shedding and seroconversion. Successful transmission occurred even when exposure time was limited to one hour, highlighting the efficiency of this transmission route. Interestingly, the B.1.1.7 variant outcompeted the lineage A variant in an airborne transmission chain after mixed infection of donors. Combined, this data indicates that the infectious dose of B.1.1.7 required for successful transmission may be lower than that of lineage A virus. The experimental proof for true aerosol transmission and the increase in the aerosol transmission potential of B.1.1.7 underscore the continuous need for assessment of novel variants and the development or preemptive transmission mitigation strategies.

scholarly journals High COVID-19 transmission potential associated with re-opening universities can be mitigated with layered interventions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ellen Brooks-Pollock ◽  
Hannah Christensen ◽  
Adam Trickey ◽  
Gibran Hemani ◽  
Emily Nixon ◽  
...  
Keyword(s):  
Prediction Interval ◽  
Mitigation Strategies ◽  
Control Measures ◽  
Transmission Model ◽  
Model Parameters ◽  
Infection Rates ◽  
First Year Students ◽  
Transmission Potential ◽  
Plausible Model ◽  
Effective Option

AbstractControlling COVID-19 transmission in universities poses challenges due to the complex social networks and potential for asymptomatic spread. We developed a stochastic transmission model based on realistic mixing patterns and evaluated alternative mitigation strategies. We predict, for plausible model parameters, that if asymptomatic cases are half as infectious as symptomatic cases, then 15% (98% Prediction Interval: 6–35%) of students could be infected during the first term without additional control measures. First year students are the main drivers of transmission with the highest infection rates, largely due to communal residences. In isolation, reducing face-to-face teaching is the most effective intervention considered, however layering multiple interventions could reduce infection rates by 75%. Fortnightly or more frequent mass testing is required to impact transmission and was not the most effective option considered. Our findings suggest that additional outbreak control measures should be considered for university settings.

The Potential for Transmission of Coronaviruses via Sports Equipment; A Cricket Case Study

2021 ◽  
Author(s):  
Rory England ◽  
Nicholas Peirce ◽  
Joseph Torresi ◽  
Sean Mitchell ◽  
Andy Harland
Keyword(s):  
Viral Load ◽  
Mitigation Strategies ◽  
Infected Person ◽  
Review Of Literature ◽  
Airborne Transmission ◽  
Social Distancing ◽  
Transmission Pathways ◽  
Respiratory Droplets

AbstractA review of literature on the role of fomites in transmission of coronaviruses informed the development of a framework which was used to qualitatively analyse a cricket case study, where equipment is shared and passed around, and identify potential mitigation strategies. A range of pathways were identified that might in theory allow coronavirus transmission from an infected person to a non-infected person via communal or personal equipment fomites or both. Eighteen percent of potential fomite based interactions were found to be non-essential to play including all contact with another persons equipment. Six opportunities to interrupt the transmission pathway were identified, including the recommendation to screen participants for symptoms prior to play. Social distancing between participants and avoiding unnecessary surface contact provides two opportunities; firstly to avoid equipment exposure to infected respiratory droplets and secondly to avoid uninfected participants touching potential fomites. Hand sanitisation and equipment sanitisation provide two further opportunities by directly inactivating coronavirus. Preventing players from touching their mucosal membranes with their hands represents the sixth potential interruption. Whilst potential fomite transmission pathways were identified, evidence suggests that viral load will be substantially reduced during surface transfer. Mitigation strategies could further reduce potential fomites, suggesting that by comparison, direct airborne transmission presents the greater risk in cricket.

scholarly journals Airborne SARS-CoV-2 Is Rapidly Inactivated by Simulated Sunlight

2020 ◽  
Vol 222 (4) ◽  
pp. 564-571 ◽  
Author(s):  
Michael Schuit ◽  
Shanna Ratnesar-Shumate ◽  
Jason Yolitz ◽  
Gregory Williams ◽  
Wade Weaver ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Decay Rate ◽  
Environmental Conditions ◽  
Decay Rates ◽  
Mitigation Strategies ◽  
Late Winter ◽  
Transmission Route ◽  
Simulated Sunlight ◽  
Early Fall

Abstract Aerosols represent a potential transmission route of COVID-19. This study examined effect of simulated sunlight, relative humidity, and suspension matrix on stability of SARS-CoV-2 in aerosols. Simulated sunlight and matrix significantly affected decay rate of the virus. Relative humidity alone did not affect the decay rate; however, minor interactions between relative humidity and other factors were observed. Mean decay rates (± SD) in simulated saliva, under simulated sunlight levels representative of late winter/early fall and summer were 0.121 ± 0.017 min−1 (90% loss, 19 minutes) and 0.306 ± 0.097 min−1 (90% loss, 8 minutes), respectively. Mean decay rate without simulated sunlight across all relative humidity levels was 0.008 ± 0.011 min−1 (90% loss, 286 minutes). These results suggest that the potential for aerosol transmission of SARS-CoV-2 may be dependent on environmental conditions, particularly sunlight. These data may be useful to inform mitigation strategies to minimize the potential for aerosol transmission.

scholarly journals Aerosol Detection and Transmission of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV): What Is the Evidence, and What Are the Knowledge Gaps?

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 712 ◽  
Author(s):  
Andréia Gonçalves Arruda ◽  
Steve Tousignant ◽  
Juan Sanhueza ◽  
Carles Vilalta ◽  
Zvonimir Poljak ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Field Conditions ◽  
Respiratory Syndrome Virus ◽  
Transmission Route ◽  
Knowledge Gaps ◽  
Airborne Transmission ◽  
Infectious Individual ◽  
Transmission Data ◽  
Outbreak Investigations ◽  
Shed Light

In human and veterinary medicine, there have been multiple reports of pathogens being airborne under experimental and field conditions, highlighting the importance of this transmission route. These studies shed light on different aspects related to airborne transmission such as the capability of pathogens becoming airborne, the ability of pathogens to remain infectious while airborne, the role played by environmental conditions in pathogen dissemination, and pathogen strain as an interfering factor in airborne transmission. Data showing that airborne pathogens originating from an infectious individual or population can infect susceptible hosts are scarce, especially under field conditions. Furthermore, even though disease outbreak investigations have generated important information identifying potential ports of entry of pathogens into populations, these investigations do not necessarily yield clear answers on mechanisms by which pathogens have been introduced into populations. In swine, the aerosol transmission route gained popularity during the late 1990’s as suspicions of airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) were growing. Several studies were conducted within the last 15 years contributing to the understanding of this transmission route; however, questions still remain. This paper reviews the current knowledge and identifies knowledge gaps related to PRRSV airborne transmission.

Reentry Following COVID-19: Concerns for Singers

2021 ◽  
Author(s):  
David Meyer ◽  
John Nix ◽  
Lynn Helding ◽  
Allen Henderson ◽  
Tom Carroll ◽  
...  
Keyword(s):  
Risk Factors ◽  
Environmental Risk ◽  
Environmental Risk Factors ◽  
Vaccine Hesitancy ◽  
Transmission Route ◽  
Airborne Transmission ◽  
Number Of Factors ◽  
Privacy Laws ◽  
Teaching Learning ◽  
Psychological Risks

The effectiveness of the two-dose COVID-19 vaccines has made reentry to in-person teaching, learning, and performing possible, despite singers’ special vulnerabilities to SARS-CoV-2 due to the virus’ airborne transmission route and the high-aerosol generating nature of singing. A number of factors may complicate a return to pre-pandemic conditions. This article provides resources to help teachers, singers, and collaborative pianists safely and ethically navigate a return to in-person singing by considering the following: effectiveness of vaccination and mask use; an update on aerosol risk; environmental risk factors and mitigation; the intersection of the privacy laws FERPA and HIPAA and vaccine hesitancy, and the psychological risks of reentry following the pandemic.

scholarly journals Analysis of Salivary Glands and Saliva from Aedes albopictus and Aedes aegypti Infected with Chikungunya Viruses

Insects ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 39 ◽  
Author(s):  
Irma Sanchez-Vargas ◽  
Laura Harrington ◽  
William Black ◽  
Ken Olson
Keyword(s):  
Salivary Glands ◽  
Transmission Efficiency ◽  
Ocean Basin ◽  
Western Hemisphere ◽  
La Réunion ◽  
Transmission Potential ◽  
Increased Risk ◽  
The Caribbean ◽  
La Réunion Island ◽  
A226v Mutation

Chikungunya virus (CHIKV) is a medically important mosquito-borne virus transmitted to humans by infected Aedes (Stegomyia) species. In 2013–2014, Ae. aegypti transmitted CHIKV to humans in the Caribbean and in 2005–2006, Ae. albopictus transmitted CHIKV on La Réunion Island (Indian Ocean basin). CHIKV LR2006 OPY1 from the La Réunion epidemic was associated with a mutation (E1:A226V) in the viral E1 glycoprotein that enhanced CHIKV transmission by Ae. albopictus. CHIKV R99659 from the Caribbean outbreak did not have the E1:A226V mutation. Here, we analyzed the salivary glands and saliva of Ae. albopictus strains from New Jersey, Florida, Louisiana and La Réunion after infection with each virus to determine their transmission potential. We infected the Ae. albopictus strains with blood meals containing 3–7 × 107 PFU/mL of each virus and analyzed the mosquitoes nine days later to maximize infection of their salivary glands. All four Ae. albopictus strains were highly susceptible to LR2006 OPY1 and R99659 viruses and their CHIKV disseminated infection rates (DIR) were statistically similar (p = 0.3916). The transmission efficiency rate (TER) was significantly lower for R99659 virus compared to LR2006 OPY1 virus in all Ae. albopictus strains and Ae. aegypti (Poza Rica) (p = 0.012) suggesting a salivary gland exit barrier to R99659 virus not seen with LR2006 OPY1 infections. If introduced, LR2006 OPY1 virus poses an increased risk of transmission by both Aedes species in the western hemisphere.

scholarly journals Airborne dispersion of droplets during coughing: a physical model of viral transmission

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongying Li ◽  
Fong Yew Leong ◽  
George Xu ◽  
Chang Wei Kang ◽  
Keng Hui Lim ◽  
...  
Keyword(s):  
Social Protection ◽  
Flow Simulation ◽  
Droplet Evaporation ◽  
Transmission Risk ◽  
Focused Attention ◽  
Droplet Dispersion ◽  
Airborne Transmission ◽  
Transmission Potential ◽  
Droplet Sizes ◽  
Low Humidity

AbstractThe Covid-19 pandemic has focused attention on airborne transmission of viruses. Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Although this model defines most airborne droplets as 8–16 µm in diameter, we infer that larger droplets of 32–40 µm in diameter may potentially be more infectious due to higher viral content. Use of face masks is therefore recommended for both personal and social protection. We found social distancing effective at reducing transmission potential across all droplet sizes. However, the presence of a human body 1 m away modifies the aerodynamics so that downstream droplet dispersion is enhanced, which has implications on safe distancing in queues. At 1 m distance, we found that an average of 0.55 viral copies is inhaled for a cough at median loading, scalable up to 340 copies at peak loading. Droplet evaporation results in significant reduction in droplet counts, but airborne transmission remains possible even under low humidity conditions.

scholarly journals From Alpha to Zeta: Identifying variants and subtypes of SARS-CoV-2 via clustering

2021 ◽  
Author(s):  
Andrew Melnyk ◽  
Fatemeh Mohebbi ◽  
Sergey Knyazev ◽  
Bikram Sahoo ◽  
Roya Hosseini ◽  
...  
Keyword(s):  
Large Datasets ◽  
Genomic Diversity ◽  
Gap Filling ◽  
Novel Variants ◽  
Very Large Datasets ◽  
Clustering Approach ◽  
Alpha Variant ◽  
The Uk ◽  
First Time ◽  
Over Time

The availability of millions of SARS-CoV-2 sequences in public databases such as GISAID and EMBL-EBI (UK) allows a detailed study of the evolution, genomic diversity and dynamics of a virus like never before. Here we identify novel variants and subtypes of SARS-CoV-2 by clustering sequences in adapting methods originally designed for haplotyping intra-host viral populations. We asses our results using clustering entropy --- the first time it has been used in this context. Our clustering approach reaches lower entropies compared to other methods, and we are able to boost this even further through gap filling and Monte Carlo based entropy minimization. Moreover, our method clearly identifies the well-known Alpha variant in the UK and GISAID datasets, but is also able to detect the much less represented (<1% of the sequences) Beta (South Africa), Epsilon (California), Gamma and Zeta (Brazil) variants in the GISAID dataset. Finally, we show that each variant identified has high selective fitness, based on the growth rate of its cluster over time. This demonstrates that our clustering approach is a viable alternative for detecting even rare subtypes in very large datasets.

scholarly journals The Facility Infection Risk Estimator™: A web application tool for comparing indoor risk mitigation strategies by estimating airborne transmission risk

2021 ◽  
pp. 1420326X2110395
Author(s):  
Marcel Harmon ◽  
Josephine Lau
Keyword(s):  
Web Application ◽  
Risk Mitigation ◽  
Infection Risk ◽  
Mitigation Strategies ◽  
Transmission Risk ◽  
Physical Parameters ◽  
Airborne Transmission ◽  
Risk Mitigation Strategies ◽  
Risk Estimator ◽  
Number Of Individuals

The COVID-19 pandemic created needs for (a) estimating the existing airborne risk of infection from SARS-CoV-2 in existing facilities and new designs and (b) estimating and comparing the impacts of engineering and behavioural strategies for contextually reducing that risk. This paper presents the development of a web application to meet these needs, the Facility Infection Risk Estimator™, and its underlying Wells–Riley based model. The model specifically estimates (a) the removal efficiencies of various settling, ventilation, filtration and virus inactivation strategies and (b) the associated probability of infection, given the room physical parameters and number of individuals infected present with either influenza or SARS-CoV-2. A review of the underlying calculations and associated literature is provided, along with the model's validation against two documented spreading events. The error between modelled and actual number of additional people infected, normalized by the number of uninfected people present, ranged from roughly –18.4% to +9.7%. The more certain one can be regarding the input parameters (such as for new designs or existing buildings with adequate field verification), the smaller these normalized errors will be, likely less than ±15%, making it useful for comparing the impacts of different risk mitigation strategies focused on airborne transmission.

Sign in / Sign up

Export Citation Format

Share Document