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School Children Unlikely to Play a Significant Role in COVID-19 Spread

AHA Publisher — Mon, 03 Aug 2020 07:00:29 +0000

Sally Robertson, B.Sc. via News-Medical Net – A study conducted by researchers in Finland suggests that children who are exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in schools are unlikely to transmit the virus further and play any significant role in the spread of coronavirus disease 2019 (COVID-19). The team’s study of exposure incidents in two different schools in Helsinki found that exposure to a 12-year-old index case did not lead to further SARS-CoV-2 transmission. In contrast, exposure to an index case, which was a staff member, did lead to further transmission. Following exposure to the adult case, the incidence of COVID-19 among children was still low, as was transmission to their household contacts. “It is likely that transmission from children to adults is limited,” writes Timothee Dub (Finnish Institute for Health and Welfare) and colleagues. The researchers say they hope the findings will help inform the prioritization of mitigation measures and reassure parents of school-aged children who are worried about the new school year starting in Autumn. A pre-print version of the paper is available on the server medRxiv*, while the article undergoes peer review. Children Were Initially Assumed to Play a Significant Role in Transmission Since the COVID-19 outbreak began in Wuhan, China, late last year, the role children play in the transmission of SARS-CoV-2 has been unclear. As the outbreak developed into a pandemic, some studies showed that children appeared to be at low risk of severe disease or death. Still, it was assumed that children might play a significant role in the transmission, and in many countries governments ordered school closures as a control measure. Schools closed in Finland on March 18th, but, at the time, very few school-related cases of COVID-19 had been reported, and the potential risk of transmission in schools was unknown. Schools were reopened again on May 14th. Early reports on school exposure where the index case was a child generated conflicting results. In France, for example, one study found that of 54 school contacts, no further transmission occurred, while another study reported a 9% attack rate, where almost half of the children were asymptomatic. Calculating Attack Rates and Identifying Transmission Chains Now, Dub and the team have conducted two retrospective cohort studies of school exposure incidents in Helsinki to assess transmission among pupils, staff, and any household contacts. “We recruited close school contacts and families of school cases, calculated attack rates (AR) on school level and families, and identified transmission chains,” writes the team. A case was defined as a person exposed at school who was positive for SARS-CoV-2 based on either reverse transcriptase-polymerase chain reaction testing or microneutralization testing. The first exposure incident (school A) involved a 12-year old index case who had been diagnosed with COVID-19, following the onset of symptoms in late February while the pupil was still attending school. Dub and colleagues identified 121 close school and sports contacts, all of whom were instructed to stay at home for 14 days. The second exposure incident (school B) involved a middle-aged staff member diagnosed with COVID-19 who had attended school for two days while experiencing symptoms, before then deciding to self-isolate. Contact tracing identified 63 exposed pupils and staff members, all of whom were told to stay at home for 14 days. Transmission Did Not Occur in School A But Did in School B In the case of school A, among 89 (74%) of the 121 close contacts who participated in the study, no further transmission was identified. In the case of school B, among 51 (81%) of 63 close contacts participating in the study, the attack rate was 16%; eight individuals were found to have COVID-19, including one member of staff. Among close household contacts of pupils who became cases, the attack rate was 31% (5 of 16), although the researchers say other plausible sources of infection were reported. “Here, we found that an adult index case could lead to further transmission among children,” say the researchers. “Age might have a role in susceptibility to SARS-CoV-2 infection in children.” However, the incidence of COVID-19 infections among children following school-related exposure was limited, as was secondary transmission among their households, says the team. The Researchers Hope the Findings Will Reassure Parents, But Say Further Research Is Needed “We hope our findings will help prioritize mitigation measures as well as reduce worry among parents of school-aged children as most EU countries are preparing for the start of a new school year in autumn,” writes the team. The researchers say further studies on COVID-19 transmission in the school setting are needed to improve recommendations for mitigation measures such as quarantine and school closures. “Starting from August 2020, the Finnish Institute for Health and Welfare will be coordinating multisite transmission studies in the five university hospital cities to understand further the role of children in SARS-CoV2 transmission chains and the role of immunity and other factors in this process,” said Dub and colleagues. To read the original article click here.

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New Method Developed to Assess the Effectiveness of Facemasks in Obstructing Droplets

AHA Publisher — Wed, 01 Jul 2020 07:00:46 +0000

Florida Atlantic University via News-Medical Net – Currently, there are no specific guidelines on the most effective materials and designs for facemasks to minimize the spread of droplets from coughs or sneezes to mitigate the transmission of COVID-19. While there have been prior studies on how medical-grade masks perform, data on cloth-based coverings used by the vast majority of the general public are sparse. Research from Florida Atlantic University’s College of Engineering and Computer Science, just published in the journal Physics of Fluids, demonstrates through visualization of emulated coughs and sneezes, a method to assess the effectiveness of facemasks in obstructing droplets. The rationale behind the recommendation for using masks or other face coverings is to reduce the risk of cross-infection via the transmission of respiratory droplets from infected to healthy individuals. Researchers employed flow visualization in a laboratory setting using a laser light sheet and a mixture of distilled water and glycerin to generate the synthetic fog that made up the content of a cough-jet. They visualized droplets expelled from a mannequin’s mouth while simulating coughing and sneezing. They tested masks that are readily available to the general public, which do not draw away from the supply of medical-grade masks and respirators for healthcare workers. They tested a single-layer bandana-style covering, a homemade mask that was stitched using two-layers of cotton quilting fabric consisting of 70 threads per inch, and a non-sterile cone-style mask that is available in most pharmacies. By placing these various masks on the mannequin, they were able to map out the paths of droplets and demonstrate how differently they perform. Results showed that loosely folded facemasks and bandana-style coverings provide minimal stopping-capability for the smallest aerosolized respiratory droplets. Well-fitted homemade masks with multiple layers of quilting fabric, and off-the-shelf cone style masks, proved to be the most effective in reducing droplet dispersal. These masks were able to curtail the speed and range of the respiratory jets significantly, albeit with some leakage through the mask material and from small gaps along the edges. Importantly, uncovered emulated coughs were able to travel noticeably farther than the currently recommended 6-foot distancing guideline. Without a mask, droplets traveled more than 8 feet; with a bandana, they traveled 3 feet, 7 inches; with a folded cotton handkerchief, they traveled 1 foot, 3 inches; with the stitched quilted cotton mask, they traveled 2.5 inches; and with the cone-style mask, droplets traveled about 8 inches. “In addition to providing an initial indication of the effectiveness of protective equipment, the visuals used in our study can help convey to the general public the rationale behind social-distancing guidelines and recommendations for using facemasks,” said Siddhartha Verma, Ph.D., lead author and an assistant professor who co-authored the paper with Manhar Dhanak, Ph.D., department chair, professor, and director of SeaTech; and John Frakenfeld, technical paraprofessional, all within FAU’s Department of Ocean and Mechanical Engineering. “Promoting widespread awareness of effective preventive measures is crucial at this time as we are observing significant spikes in cases of COVID-19 infections in many states, especially Florida.” When the mannequin was not fitted with a mask, they projected droplets much farther than the 6-foot distancing guidelines currently recommended by the United States Centers for Disease Control and Prevention. The researchers observed droplets traveling up to 12 feet within approximately 50 seconds. Moreover, the tracer droplets remained suspended midair for up to three minutes in the quiescent environment. These observations, in combination with other recent studies, suggest that current social-distancing guidelines may need to be updated to account for aerosol-based transmission of pathogens. “We found that although the unobstructed turbulent jets were observed to travel up to 12 feet, a large majority of the ejected droplets fell to the ground by this point,” said Dhanak. “Importantly, both the number and concentration of the droplets will decrease with increasing distance, which is the fundamental rationale behind social-distancing.” The pathogen responsible for COVID-19 is found primarily in respiratory droplets that are expelled by infected individuals during coughing, sneezing, or even talking and breathing. Apart from COVID-19, respiratory droplets also are the primary means of transmission for various other viral and bacterial illnesses, such as the common cold, influenza, tuberculosis, SARS (Severe Acute Respiratory Syndrome), and MERS (Middle East Respiratory Syndrome), to name a few. These pathogens are enveloped within respiratory droplets, which may land on healthy individuals and result in direct transmission, or on inanimate objects, which can lead to infection when a healthy individual comes in contact with them. “Our researchers have demonstrated how masks are able to significantly curtail the speed and range of the respiratory droplets and jets. Moreover, they have uncovered how emulated coughs can travel noticeably farther than the currently recommended six-foot distancing guideline,” Stella Batalama, Ph.D., Dean, Florida Atlantic University College of Engineering and Computer Science “Their research outlines the procedure for setting up simple visualization experiments using easily available materials, which may help healthcare professionals, medical researchers, and manufacturers in assessing the effectiveness of face masks and other personal protective equipment qualitatively.” To read the original article click here.

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Development of New System for Combatting COVID-19 That Can Be Used for Other Viruses

AHA Publisher — Wed, 08 Apr 2020 07:00:01 +0000

University of Texas Medical Branch at Galveston via EurekAlert – A multidisciplinary team at The University of Texas Medical Branch at Galveston working to combat the COVID-19 virus has a system that will unlock researchers’ ability to more quickly develop and evaluate developing vaccines, diagnose infected patients and explore whether or how the virus has evolved. GALVESTON, Texas – The scientists, led by Pei-Yong Shi, developed the system by engineering a reverse genetic system for SARS coronavirus 2, or SARS-CoV-2, that is causing the current COVID-19 pandemic. The study is currently available in Cell Host & Microbe. A Reverse genetic system is one of the most useful tools for studying and combatting viruses. The system allows researchers to make the virus in the lab and manipulate it in a petri dish. Using this system, the UTMB team has engineered a version of the SARS-CoV-2 virus that is labeled with neon green. When the labeled virus infects a cell, the infected cell turns green. “The labeled virus could be used to rapidly determine whether a patient has already been infected by the new coronavirus or evaluate how well developing vaccines are inducing antibodies that block infection of the virus. The level of antibodies induced by a vaccine is the most important parameter in predicting how well a vaccine works,” said Shi, I.H. Kempner professor of Human Genetics at UTMB. “The neon green labeled virus system allows us to test patients’ samples in 12 hours in a high-throughput manner that tests many samples at once. In contrast, the conventional method can only test a few specimens at a time with a long turnaround time of a week.” “This technology can significantly reduce how long it takes to evaluate developing vaccines and ultimately bring them to the market,” said Xuping Xie, the UTMB Research Scientist who designed and developed the genetic system. “UTMB will be very happy to make this technology widely available to both academia and industry researchers working to quickly develop countermeasures.” “The genetic system allows us to study the evolution of the new coronavirus. This will help us to understand how the virus jumped from its original host bat species to humans. It remains to be determined if an intermediate host is required for the host switch from the original bats to humans for the new coronavirus,” said Vineet Menachery, Assistant Professor at UTMB, who co-senior-authored the study. “The system has provided a critical tool for the research community.” “This is another example of team science at UTMB,” said Dr. Ben Raimer, President ad Interim of UTMB. “The collective effort from teams with complementary expertise worked together to deliver this exciting study. We will expand the team science to areas of clinical care and patient diagnosis by deploying the technology for serological testing.” Shi said, “This will not be the last emerging virus that plagues humanity. In the past two decades, we’ve seen other coronaviruses like SARS and MERS, as well as other viruses like Zika, Ebola and others. It’s critically important to have a system that can be used for any new future or re-emerging viruses so that we can very quickly respond to the pathogens and protect peoples’ health.” To read the original article click here.

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