Il link selezionato consente di accedere a siti web di terzi, che si pongono al di fuori del controllo da parte di Fondazione Internazionale Menarini . Pertanto, Fondazione Internazionale Menarini non potrà essere in alcun modo ritenuta responsabile né del contenuto di detti siti web (ivi inclusi, in via esemplificativa ma non esaustiva, i link contenuti al loro interno) né di eventuali acquisti o altre operazioni effettuate per il tramite di tali siti web. L'accesso e l'uso di siti web di terzi è a rischio dell'utente ed è soggetto alle condizioni di utilizzo di tali siti, che si consiglia di leggere con attenzione.
Read More »
Susanna Esposito, Nicola Cotugno, Nicola Principi
Although several studies have tried to evaluate the real efficacy of school closure for pandemic control over time, no definitive answer to this question has been given. Moreover, it has not been clarified whether children or teenagers could be considered a problem for SARS-CoV-2 diffusion or, on the contrary, whether parents and school workers play a greater role. The aims of this review are to discuss about children’s safety at school and the better strategies currently able to reduce the risk of SARS-CoV-2 infection at school.
Compared to adults, very few cases of COVID-19 were diagnosed in children, who generally suffered from an asymptomatic infection or a mild disease. Moreover, school closure is systematically associated with the development of problems involving students, teachers and parents, particularly among populations with poor resources. Although several researches have tried to evaluate the real efficacy of school closure for pandemic control over time, no definitive answer to this question has been given. Available findings seem to confirm that to ensure adequate learning and to avoid social and economic problems, schools must remain open, provided that the adults who follow children at home and at school absolutely comply with recommendations for prevention measures and that school facilities can be optimized in order to significantly reduce the spread of infection. In this regard, the universal use of face masks in addition to hand hygiene and safe distancing in schools, at least starting from the age of 6 years, seems extremely useful. Moreover, since the beginning of the COVID-19 outbreak the use of telemedicine to manage suspected SARS-CoV-2-infected individuals in the community has appeared to be an easy and effective measure to solve many paediatric problems and could represent a further support to schools .
We think that schools must remain open, despite COVID-19 pandemic. However, several problems strictly related to school frequency and reduction of infectious risk must be solved before school attendance can be considered completely safe. A single more in-depth guideline agreed between countries with the same school problems could be very useful in eliminating doubts and fostering the compliance of students, teachers and non-teaching school staff reducing errors and misinterpretations.
Michael A. Johansson, Talia M. Quandelacy, Sarah Kada, Pragati Venkata Prasad, Molly Steele, John T. Brooks, Rachel B. Slayton, Matthew Biggerstaff, Jay C. Butler
Importance Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiology of coronavirus disease 2019 (COVID-19), is readily transmitted person to person. Optimal control of COVID-19 depends on directing resources and health messaging to mitigation efforts that are most likely to prevent transmission, but the relative importance of such measures has been disputed.
Objective To assess the proportion of SARS-CoV-2 transmissions in the community that likely occur from persons without symptoms.
Design, Setting, and Participants This decision analytical model assessed the relative amount of transmission from presymptomatic, never symptomatic, and symptomatic individuals across a range of scenarios in which the proportion of transmission from people who never develop symptoms (ie, remain asymptomatic) and the infectious period were varied according to published best estimates. For all estimates, data from a meta-analysis was used to set the incubation period at a median of 5 days. The infectious period duration was maintained at 10 days, and peak infectiousness was varied between 3 and 7 days (−2 and +2 days relative to the median incubation period). The overall proportion of SARS-CoV-2 was varied between 0% and 70% to assess a wide range of possible proportions.
Main Outcomes and Measures Level of transmission of SARS-CoV-2 from presymptomatic, never symptomatic, and symptomatic individuals.
Results The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms.
Conclusions and Relevance In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.
Fengjuan Chen, Bosheng Li, Peter Hao, Yang Song, Wenbo Xu, Nankun Liu, Chunliang Lei, Changwen Ke
Paolo Bosetti, Cécile Tran Kiem, Yazdan Yazdanpanah, Arnaud Fontanet, Bruno Lina, Vittoria Colizza, Simon Cauchemez
We used a mathematical model to evaluate the impact of mass testing in the control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Under optimistic assumptions, one round of mass testing may reduce daily infections by up to 20–30%. Consequently, very frequent testing would be required to control a quickly growing epidemic if other control measures were to be relaxed. Mass testing is most relevant when epidemic growth remains limited through a combination of interventions.
Kathy Leung, Marcus HH Shum, Gabriel M Leung, Tommy TY Lam, Joseph T Wu
Two new SARS-CoV-2 lineages with the N501Y mutation in the receptor-binding domain of the spike protein spread rapidly in the United Kingdom. We estimated that the earlier 501Y lineage without amino acid deletion Δ69/Δ70, circulating mainly between early September and mid-November, was 10% (6–13%) more transmissible than the 501N lineage, and the 501Y lineage with amino acid deletion Δ69/Δ70, circulating since late September, was 75% (70–80%) more transmissible than the 501N lineage
Tomoya Sagawa, Takahiro Tsujikawa, Akiko Honda, Natsuko Miyasaka, Michitaka Tanaka, Takashi Kida, Koichi Hasegawa, Tomoaki Okuda, Yutaka Kawahito, Hirohisa Takano
ISTAT (ISTITUTO NAZIONALE DI STATISTICA)
ISTAT (ISTITUTO NAZIONALE DI STATISTICA)
THE NEW ENGLAND JOURNAL OF MEDICINE
L.R. Baden, H.M. El Sahly, B. Essink, K. Kotloff, S. Frey, R. Novak, D. Diemert, S.A. Spector, N. Rouphael, C.B. Creech, J. McGettigan, S. Khetan, N. Segall, J. Solis, A. Brosz, C. Fierro, H. Schwartz, K. Neuzil, L. Corey, P. Gilbert, H. Janes, D. Follmann, M. Marovich, J. Mascola, L. Polakowski, J. Ledgerwood, B.S. Graham, H. Bennett, R. Pajon, C. Knightly, B. Leav, W. Deng, H. Zhou, S. Han, M. Ivarsson, J. Miller, T. Zaks
Vaccines are needed to prevent coronavirus disease 2019 (Covid-19) and to protect
persons who are at high risk for complications. The mRNA-1273 vaccine is a lipid
nanoparticle–encapsulated mRNA-based vaccine that encodes the prefusion stabi-
lized full-length spike protein of the severe acute respiratory syndrome corona-
virus 2 (SARS-CoV-2), the virus that causes Covid-19.
This phase 3 randomized, observer-blinded, placebo-controlled trial was conducted
at 99 centers across the United States. Persons at high risk for SARS-CoV-2 infec-
tion or its complications were randomly assigned in a 1:1 ratio to receive two intra-
muscular injections of mRNA-1273 (100 μg) or placebo 28 days apart. The pri-
mary end point was prevention of Covid-19 illness with onset at least 14 days after
the second injection in participants who had not previously been infected with
The trial enrolled 30,420 volunteers who were randomly assigned in a 1:1 ratio to
receive either vaccine or placebo (15,210 participants in each group). More than
96% of participants received both injections, and 2.2% had evidence (serologic,
virologic, or both) of SARS-CoV-2 infection at baseline. Symptomatic Covid-19 ill-
ness was confirmed in 185 participants in the placebo group (56.5 per 1000 person-
years; 95% confidence interval [CI], 48.7 to 65.3) and in 11 participants in the mRNA-
1273 group (3.3 per 1000 person-years; 95% CI, 1.7 to 6.0); vaccine efficacy was
94.1% (95% CI, 89.3 to 96.8%; P<0.001). Efficacy was similar across key secondary
analyses, including assessment 14 days after the first dose, analyses that included
participants who had evidence of SARS-CoV-2 infection at baseline, and analyses
in participants 65 years of age or older. Severe Covid-19 occurred in 30 partici-
pants, with one fatality; all 30 were in the placebo group. Moderate, transient re-
actogenicity after vaccination occurred more frequently in the mRNA-1273 group.
Serious adverse events were rare, and the incidence was similar in the two groups.
The mRNA-1273 vaccine showed 94.1% efficacy at preventing Covid-19 illness,
including severe disease. Aside from transient local and systemic reactions, no
safety concerns were identified. (Funded by the Biomedical Advanced Research
and Development Authority and the National Institute of Allergy and Infectious
Diseases; COVE ClinicalTrials.gov number, NCT04470427.
Belinda Hengel, Louise Causer, Susan Matthews, Kirsty Smith, Kelly Andrewartha, Steven Badman, Brooke Spaeth, Annie Tangey, Phillip Cunningham, Emily Phillips, James Ward, Caroline Watts, Jonathan King, Tanya Applegate, Mark Shephard, Rebecca Guy
Michael G Baker, Nick Wilson, Tony Blakely
Yea-Hung Chen, M. Maria Glymour, Ralph Catalano, Alicia Fernandez, Tung Nguyen, Margot Kushel, Kirsten Bibbins-Domingo
Angela L. Rasmussen
HARVARD T.H. CHAN
Jan M. Brauner, Sören Mindermann, Mrinank Sharma, David Johnston, John Salvatier, Tomáš Gavenčiak, Anna B. Stephenson, Gavin Leech, George Altman, Vladimir Mikulik, Alexander John Norman, Joshua Teperowski Monrad, Tamay Besiroglu, Hong Ge, Meghan A. Hartwick, Yee Whye Teh, Leonid Chindelevitch, Yarin Gal, Jan Kulveit
Governments are attempting to control the COVID-19 pandemic with nonpharmaceutical interventions (NPIs). However, the effectiveness of different NPIs at reducing transmission is poorly understood. We gathered chronological data on the implementation of NPIs for several European, and other, countries between January and the end of May 2020. We estimate the effectiveness of NPIs, ranging from limiting gathering sizes, business closures, and closure of educational institutions to stay-at-home orders. To do so, we used a Bayesian hierarchical model that links NPI implementation dates to national case and death counts and supported the results with extensive empirical validation. Closing all educational institutions, limiting gatherings to 10 people or less, and closing face-to-face businesses each reduced transmission considerably. The additional effect of stay-at-home orders was comparatively small.
Valentina Marziano, Giorgio Guzzetta, Bruna Maria Rondinone, Fabio Boccuni, Flavia Riccardo, Antonino Bella, Piero Poletti, Filippo Trentini, Patrizio Pezzotti, Silvio Brusaferro, Giovanni Rezza, Sergio Iavicoli, Marco Ajelli, Stefano Merler
After the national lockdown imposed on March 11, 2020, the Italian government has gradually resumed the suspended economic and social activities since May 4, while maintaining the closure of schools until September 14. We use a model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission to estimate the health impact of different exit strategies. The strategy adopted in Italy kept the reproduction number Rt at values close to one until the end of September, with marginal regional differences. Based on the estimated postlockdown transmissibility, reopening of workplaces in selected industrial activities might have had a minor impact on the transmissibility. Reopening educational levels in May up to secondary schools might have influenced SARS-CoV-2 transmissibility only marginally; however, including high schools might have resulted in a marked increase of the disease burden. Earlier reopening would have resulted in disproportionately higher hospitalization incidence. Given community contacts in September, we project a large second wave associated with school reopening in the fall.
Elisabetta Larosa, Olivera Djuric, Mariateresa Cassinadri, Silvia Cilloni, Eufemia Bisaccia, Massimo Vicentini, Francesco Venturelli, Paolo Giorgi Rossi, Patrizio Pezzotti, Emanuela Bedeschi
We report epidemiological investigations of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 41 classes of 36 schools in Reggio Emilia province, northern Italy, from their reopening on 1 September to 15 October 2020. The overall secondary case attack rate was 3.2%, reaching 6.6% in middle and high schools. More timely isolation and testing of classmates could be effective in reducing virus transmission in this setting.
Jacob E. Lemieux, Katherine J. Siddle, Bennett M. Shaw, Christine Loreth, Stephen F. Schaffner, Adrianne Gladden-Young, Gordon Adams, Timelia Fink, Christopher H. Tomkins-Tinch, Lydia A. Krasilnikova, Katherine C. DeRuff, Melissa Rudy, Matthew R. Bauer, Kim A. Lagerborg, Erica Normandin, Sinéad B. Chapman, Steven K. Reilly, Melis N. Anahtar, Aaron E. Lin, Amber Carter, Cameron Myhrvold, Molly E. Kemball, Sushma Chaluvadi, Caroline Cusick, Katelyn Flowers, Anna Neumann, Felecia Cerrato, Maha Farhat, Damien Slater, Jason B. Harris, John A. Branda, David Hooper, Jessie M. Gaeta, Travis P. Baggett, James O’Connell, Andreas Gnirke, Tami D. Lieberman, Anthony Philippakis, Meagan Burns, Catherine M. Brown, Jeremy Luban, Edward T. Ryan, Sarah E. Turbett, Regina C. LaRocque, William P. Hanage, Glen R. Gallagher, Lawrence C. Madoff, Sandra Smole, Virginia M. Pierce, Eric Rosenberg, Pardis C. Sabeti, Daniel J. Park, Bronwyn L. MacInnis
Analysis of 772 complete SARS-CoV-2 genomes from early in the Boston area epidemic revealed numerous introductions of the virus, a small number of which led to most cases. The data revealed two superspreading events. One, in a skilled nursing facility, led to rapid transmission and significant mortality in this vulnerable population but little broader spread, while other introductions into the facility had little effect. The second, at an international business conference, produced sustained community transmission and was exported, resulting in extensive regional, national, and international spread. The two events also differed significantly in the genetic variation they generated, suggesting varying transmission dynamics in superspreading events. Our results show how genomic epidemiology can help understand the link between individual clusters and wider community spread.
Benjamin J Cowling, Gabriel M Leung
Phillip W. Clapp, Emily E. Sickbert-Bennett, James M. Samet, Jon Berntsen, Kirby L. Zeman, Deverick J. Anderson, David J. Weber, William D. Bennett
Importance During the coronavirus disease 2019 (COVID-19) pandemic, the general public has been advised to wear masks or improvised face coverings to limit transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, there has been considerable confusion and disagreement regarding the degree to which masks protect the wearer from airborne particles.
Objectives To evaluate the fitted filtration efficiency (FFE) of various consumer-grade and improvised face masks, as well as several popular modifications of medical procedure masks that are intended to improve mask fit or comfort.
Design, Setting, and Participants For this study conducted in a research laboratory between June and August 2020, 7 consumer-grade masks and 5 medical procedure mask modifications were fitted on an adult male volunteer, and FFE measurements were collected during a series of repeated movements of the torso, head, and facial muscles as outlined by the US Occupational Safety and Health Administration Quantitative Fit Testing Protocol. The consumer-grade masks tested included (1) a 2-layer woven nylon mask with ear loops that was tested with an optional aluminum nose bridge and nonwoven filter insert in place, (2) a cotton bandana folded diagonally once (ie, “bandit” style) or in a (3) multilayer rectangle according to the instructions presented by the US Surgeon General, (4) a single-layer woven polyester/nylon mask with ties, (5) a nonwoven polypropylene mask with fixed ear loops, (6) a single-layer woven polyester gaiter/neck cover balaclava bandana, and (7) a 3-layer woven cotton mask with ear loops. Medical procedure mask modifications included (1) tying the mask’s ear loops and tucking in the side pleats, (2) fastening ear loops behind the head with 3-dimensional–printed ear guards, (3) fastening ear loops behind the head with a claw-type hair clip, (4) enhancing the mask/face seal with rubber bands over the mask, and (5) enhancing the mask/face seal with a band of nylon hosiery over the fitted mask.
Main Outcomes and Measures The primary study outcome was the measured FFE of common consumer-grade and improvised face masks, as well as several popular modifications of medical procedure masks.
Results The mean (SD) FFE of consumer grade masks tested on 1 adult male with no beard ranged from 79.0% (4.3%) to 26.5% (10.5%), with the 2-layer woven nylon mask having the highest FFE. Unmodified medical procedure masks with ear loops had a mean (SD) FFE of 38.5% (11.2%). All modifications evaluated in this study increased procedure mask FFE (range [SD], 60.3% [11.1%] to 80.2% [3.1%]), with a nylon hosiery sleeve placed over the procedure mask producing the greatest improvement.
Conclusions and Relevance While modifications to improve medical procedure mask fit can enhance the filtering capability and reduce inhalation of airborne particles, this study demonstrates that the FFEs of consumer-grade masks available to the public are, in many cases, nearly equivalent to or better than their non-N95 respirator medical mask counterparts.
Flavia Riccardo, Marco Ajelli, Xanthi D Andrianou, Antonino Bella, Martina Del Manso, Massimo Fabiani, Stefania Bellino, Stefano Boros, Alberto Mateo Urdiales, Valentina Marziano, Maria Cristina Rota, Antonietta Filia, Fortunato D’Ancona, Andrea Siddu, Ornella Punzo, Filippo Trentini, Giorgio Guzzetta, Piero Poletti, Paola Stefanelli, Maria Rita Castrucci, Alessandra Ciervo, Corrado Di Benedetto, Marco Tallon, Andrea Piccioli, Silvio Brusaferro, Giovanni Rezza, Stefano Merler, Patrizio Pezzotti
On 20 February 2020, a locally acquired coronavirus disease (COVID-19) case was detected in Lombardy, Italy. This was the first signal of ongoing transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the country. The number of cases in Italy increased rapidly and the country became the first in Europe to experience a SARS-CoV-2 outbreak.
Our aim was to describe the epidemiology and transmission dynamics of the first COVID-19 cases in Italy amid ongoing control measures.
We analysed all RT-PCR-confirmed COVID-19 cases reported to the national integrated surveillance system until 31 March 2020. We provide a descriptive epidemiological summary and estimate the basic and net reproductive numbers by region.
Of the 98,716 cases of COVID-19 analysed, 9,512 were healthcare workers. Of the 10,943 reported COVID-19-associated deaths (crude case fatality ratio: 11.1%) 49.5% occurred in cases older than 80 years. Male sex and age were independent risk factors for COVID-19 death. Estimates of R0 varied between 2.50 (95% confidence interval (CI): 2.18–2.83) in Tuscany and 3.00 (95% CI: 2.68–3.33) in Lazio. The net reproduction number Rt in northern regions started decreasing immediately after the first detection.
The COVID-19 outbreak in Italy showed a clustering onset similar to the one in Wuhan, China. R0 at 2.96 in Lombardy combined with delayed detection explains the high case load and rapid geographical spread. Overall, Rt in Italian regions showed early signs of decrease, with large diversity in incidence, supporting the importance of combined non-pharmacological control measures.
Koen B Pouwels*, Thomas House*, Emma Pritchard, Julie V Robotham, Paul J Birrell, Andrew Gelman, Karina-Doris Vihta, Nikola Bowers, Ian Boreham, Heledd Thomas, James Lewis, Iain Bell, John I Bell, John N Newton, Jeremy Farrar, Ian Diamond, Pete Benton, Ann Sarah Walker
CAMBRIDGE UNIVERSITY PRESS
C.F. Yung, E. Saffari, C. Liew
The epidemiological target of lockdowns is to drive down the effective reproduction number
(Rt) to less than 1. A key unknown is the duration that lockdowns need to be in place to
achieve this and which lockdown measures are effective. Daily number of laboratory
confirmed community COVID-19 cases were extracted from regular reports from the
Ministry of Health Singapore (3) from March 20, 2020 to May 4, 2020. We generated daily
Rt to estimate the time needed for these public health lockdown measures to control the
spread of SARS-CoV-2 as demonstrated by Rt <1. It took about 14 days of nationwide
lockdown for the Rt trend to change and start falling. The upper limit of the 95% confidence
interval for time to Rt < 1 was day 15 of lockdown. We have shown that it is possible to start
‘bending the Rt curve’ about 2 weeks after implementation of specific lockdown measures
with strict compliance.
Martin Reichert, Massimo Sartelli, Markus A. Weigand, Christoph Doppstadt, Matthias Hecker, Alexander Reinisch-Liese, Fabienne Bender, Ingolf Askevold, Winfried Padberg, Federico Coccolini, Fausto Catena, Andreas Hecker
The SARS-CoV-2 pandemic is a major challenge for health care services worldwide. It’s impact on oncologic therapies and elective surgery has been described recently, and the literature provides guidelines regarding appropriate elective patient treatment during the pandemic. However, the impact of SARS-CoV-2 pandemic on emergency surgery services has been poorly investigated up to now.
A 17-item web survey had been distributed to emergency surgeons in June 2020 around the world, investigating the impact of SARS-CoV-2 pandemic on patients and septic diseases both requiring emergency surgery and the time-to-intervention in emergency surgery routine, as well as experiences with surgery in COVID-19 patients.
Ninety-eight collaborators from 31 countries responded to the survey. The majority (65.3%) estimated the impact of the SARS-CoV-2 pandemic on emergency surgical patient care as being strong or very strong. Due to the pandemic, 87.8% reported a decrease in the total number of patients undergoing emergency surgery and approximately 25% estimated a delay of more than 2 h in the time-to-diagnosis and another 2 h in the time-to-intervention. Fifty percent make structural problems with in-hospital logistics (e.g. transport of patients, closed normal wards etc.) mainly responsible for delayed emergency surgery and the frequent need (56.1%) for a triage of emergency surgical patients. 56.1% of the collaborators observed more severe septic abdominal diseases during the pandemic, especially for perforated appendicitis and severe septic cholecystitis (41.8% and 40.2%, respectively). 62.2% had experiences with surgery in COVID-19-infected patients.
The results of The WSES COVID-19 emergency surgery survey are alarming. The combination of an estimated decrease in numbers of emergency surgical patients and an observed increase in more severe septic diseases may be a result of the fear of patients from infection with COVID-19 and a consecutive delayed hospital admission and diagnosis. A critical delay in time-to-diagnosis and time-to-intervention may be a result of changes in in-hospital logistics and operating room as well as intensive care capacities. Both reflect the potentially harmful impact of SARS-CoV-2 pandemic on emergency surgery services.
CDC (CENTERS FOR DISEASE CONTROL AND PREVENTION)
Antonella Amendola, Silvia Bianchi, Maria Gori, Daniela Colzani, Marta Canuti, Elisa Borghi, Mario C. Raviglione, Gian Vincenzo Zuccotti, Elisabetta Tanzi
We identified severe acute respiratory syndrome coronavirus 2 RNA in an oropharyngeal swab specimen collected from a child with suspected measles in early December 2019, ≈3 months before the first identified coronavirus disease case in Italy. This finding expands our knowledge on timing and mapping of novel coronavirus transmission pathways.
Timothy W Russell, Joseph T Wu, Sam Clifford, W John Edmunds, Adam J Kucharski, Mark Jit
Simiao Chen, Qiushi Chen, Juntao Yang, Lin Lin, Linye Li, Lirui Jiao, Pascal Geldsetzer, Chen Wang, Annelies Wilder-Smith, Till Bärnighausen
In many countries, patients with mild coronavirus disease 2019 (COVID-19) are told to self-isolate at home, but imperfect compliance and shared living space with uninfected people limit the effectiveness of home-based isolation. We aim to examine the impact of facility-based isolation compared to self-isolation at home on the continuing epidemic in the United States.
We developed a compartment model to simulate the dynamic transmission of COVID-19 and calibrated it to key epidemic measures in the United States from March to September. We simulated facility-based isolation strategies with various capacities and starting times under different diagnosis rates. The primary model outcomes included the reduction of new infections and deaths over two months from October onwards. We further explored different effects of facility-based isolation under different epidemic burdens by major US Census Regions, and performed sensitivity analyses by varying key model assumptions and parameters.
We projected that facility-based isolation with moderate capacity of 5 beds per 10 000 total population could avert 4.17 (95% Credible Interval 1.65–7.11) million new infections and 16 000 (8000-23 000) deaths in two months compared with home-based isolation, equivalent to relative reductions of 57% (44–61%) in new infections and 37% (27–40%) in deaths. Facility-based isolation with high capacity of 10 beds per 10 000 population would achieve greater reduction of 76% (62–84%) in new infections and 52% (37–64%) in deaths when supported by the expanded testing with a 20% daily diagnosis rate. Delays in implementation would substantially reduce the impact of facility-based isolation. The effective capacity and the impact of facility-based isolation varied by epidemic stage across regions.
Timely facility-based isolation for mild COVID-19 cases could substantially reduce the number of new infections and effectively curb the continuing epidemic compared to home-based isolation. The local epidemic burden should determine the effective scale of facility-based isolation strategies.
Ruiyuan Zhang, Huiying Liang, Jinling Tang
Tommaso Celeste Bulfone, Mohsen Malekinejad, George W Rutherford, Nooshin Razani
While risk of outdoor transmission of respiratory viral infections is hypothesized to be low, there is limited data of SARS-CoV-2 transmission in outdoor compared to indoor settings.
We conducted a systematic review of peer-reviewed papers indexed in PubMed, EMBASE and Web of Science and pre-prints in Europe PMC through August 12 th, 2020 that described cases of human transmission of SARS-CoV-2. Reports of other respiratory virus transmission were included for reference.
Five identified studies found that a low proportion of reported global SARS-CoV-2 infections have occurred outdoors (<10%) and the odds of indoor transmission was very high compared to outdoors (18.7 times; 95% CI 6.0, 57.9). Five studies described influenza transmission outdoors and two described adenovirus transmission outdoors. There was high heterogeneity in study quality and individual definitions of outdoor settings which limited our ability to draw conclusions about outdoor transmission risks. In general, factors such as duration and frequency of personal contact, lack of personal protective equipment and occasional indoor gathering during a largely outdoor experience were associated with outdoor reports of infection.
Existing evidence supports the wide-held belief that the the risk of SARS-CoV-2 transmission is lower outdoors but there are significant gaps in our understanding of specific pathways.
JOURNAL OF THE PEDIATRIC INFECTIOUS DISEASES SOCIETY
Chaya Pitman-Hunt, Jacqueline Leja, Zahra M Jiwani, Dominique Rondot, Jocelyn Ang, Nirupama Kannikeswaran
This is a single center US retrospective study of infection patterns among household sick contacts of children with confirmed Severe Acute Respiratory Syndrome – Coronavirus 2 (SARS-CoV-2) infection in an urban setting. A household sick contact (HHSC) was identified in fewer than half (42%) of patients and no child-to-adult transmission was identified.
Kristina L. Bajema, Ryan E. Wiegand, Kendra Cuffe, Sadhna V. Patel, Ronaldo Iachan, Travis Lim, Adam Lee, Davia Moyse, Fiona P. Havers, Lee Harding, Alicia M. Fry, Aron J. Hall, Kelly Martin, Marjorie Biel, Yangyang Deng, William A. Meyer III, Mohit Mathur, Tonja Kyle, Adi V. Gundlapalli, Natalie J. Thornburg, Lyle R. Petersen, Chris Edens
Importance Case-based surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection likely underestimates the true prevalence of infections. Large-scale seroprevalence surveys can better estimate infection across many geographic regions.
Objective To estimate the prevalence of persons with SARS-CoV-2 antibodies using residual sera from commercial laboratories across the US and assess changes over time.
Design, Setting, and Participants This repeated, cross-sectional study conducted across all 50 states, the District of Columbia, and Puerto Rico used a convenience sample of residual serum specimens provided by persons of all ages that were originally submitted for routine screening or clinical management from 2 private clinical commercial laboratories. Samples were obtained during 4 collection periods: July 27 to August 13, August 10 to August 27, August 24 to September 10, and September 7 to September 24, 2020.
Exposures Infection with SARS-CoV-2.
Main Outcomes and Measures The proportion of persons previously infected with SARS-CoV-2 as measured by the presence of antibodies to SARS-CoV-2 by 1 of 3 chemiluminescent immunoassays. Iterative poststratification was used to adjust seroprevalence estimates to the demographic profile and urbanicity of each jurisdiction. Seroprevalence was estimated by jurisdiction, sex, age group (0-17, 18-49, 50-64, and ≥65 years), and metropolitan/nonmetropolitan status.
Results Of 177 919 serum samples tested, 103 771 (58.3%) were from women, 26 716 (15.0%) from persons 17 years or younger, 47 513 (26.7%) from persons 65 years or older, and 26 290 (14.8%) from individuals living in nonmetropolitan areas. Jurisdiction-level seroprevalence over 4 collection periods ranged from less than 1% to 23%. In 42 of 49 jurisdictions with sufficient samples to estimate seroprevalence across all periods, fewer than 10% of people had detectable SARS-CoV-2 antibodies. Seroprevalence estimates varied between sexes, across age groups, and between metropolitan/nonmetropolitan areas. Changes from period 1 to 4 were less than 7 percentage points in all jurisdictions and varied across sites.
Conclusions and Relevance This cross-sectional study found that as of September 2020, most persons in the US did not have serologic evidence of previous SARS-CoV-2 infection, although prevalence varied widely by jurisdiction. Biweekly nationwide testing of commercial clinical laboratory sera can play an important role in helping track the spread of SARS-CoV-2 in the US.
JKMS (THE KOREAN ACADEMY OF MEDICAL SCIENCES)
Keun-Sang Kwon, Jung-Im Park, Young Joon Park, Don-Myung Jung, Ki-Wahn Ryu, Ju-Hyung Lee
The transmission mode of severe acute respiratory syndrome coronavirus 2 is primarily known as droplet transmission. However, a recent argument has emerged about the possibility of airborne transmission. On June 17, there was a coronavirus disease 2019 (COVID-19) outbreak in Korea associated with long distance droplet transmission.
The epidemiological investigation was implemented based on personal interviews and data collection on closed-circuit television images, and cell phone location data. The epidemic investigation support system developed by the Korea Disease Control and Prevention Agency was used for contact tracing. At the restaurant considered the site of exposure, air flow direction and velocity, distances between cases, and movement of visitors were investigated.
A total of 3 cases were identified in this outbreak, and maximum air flow velocity of 1.2 m/s was measured between the infector and infectee in a restaurant equipped with ceiling-type air conditioners. The index case was infected at a 6.5 m away from the infector and 5 minutes exposure without any direct or indirect contact.
Droplet transmission can occur at a distance greater than 2 m if there is direct air flow from an infected person. Therefore, updated guidelines involving prevention, contact tracing, and quarantine for COVID-19 are required for control of this highly contagious disease.
Shiyi Cao, Yong Gan, Chao Wang, Max Bachmann, Shanbo Wei, Jie Gong, Yuchai Huang, Tiantian Wang, Liqing Li, Kai Lu, Heng Jiang, Yanhong Gong, Hongbin Xu, Xin Shen, Qingfeng Tian, Chuanzhu Lv, Fujian Song, Xiaoxv Yin, Zuxun Lu
Stringent COVID-19 control measures were imposed in Wuhan between January 23 and April 8, 2020. Estimates of the prevalence of infection following the release of restrictions could inform post-lockdown pandemic management. Here, we describe a city-wide SARS-CoV-2 nucleic acid screening programme between May 14 and June 1, 2020 in Wuhan. All city residents aged six years or older were eligible and 9,899,828 (92.9%) participated. No new symptomatic cases and 300 asymptomatic cases (detection rate 0.303/10,000, 95% CI 0.270–0.339/10,000) were identified. There were no positive tests amongst 1,174 close contacts of asymptomatic cases. 107 of 34,424 previously recovered COVID-19 patients tested positive again (re-positive rate 0.31%, 95% CI 0.423–0.574%). The prevalence of SARS-CoV-2 infection in Wuhan was therefore very low five to eight weeks after the end of lockdown.
Valeria Cento,Claudia Alteri,Marco Merli,Federica Di Ruscio,Livia Tartaglione,Roberto Rossotti,Giovanna Travi,Marta Vecchi,Alessandro Raimondi,Alice Nava,Luna Colagrossi,Roberto Fumagalli,Nicola Ughi,Oscar Massimiliano Epis,Diana Fanti,Andrea Beretta,Filippo Galbiati,Francesco Scaglione,Chiara Vismara,Massimo Puoti,Daniela Campisi,Carlo Federico Perno
Through a hospital-based SARS-CoV-2 molecular and serological screening, we evaluated the effectiveness of two months of lockdown and two of surveillance, in Milan, Lombardy, the first to be overwhelmed by COVID-19 pandemics during March-April 2020.
All subjects presenting at the major hospital of Milan from May-11 to July-5, 2020, underwent a serological screening by chemiluminescent assays. Those admitted were further tested by RT-PCR.
The cumulative anti-N IgG seroprevalence in the 2753 subjects analyzed was of 5.1% (95%CI = 4.3%-6.0%), with a peak of 8.4% (6.1%-11.4%) 60–63 days since the peak of diagnoses (March-20). 31/106 (29.2%) anti-N reactive subjects had anti-S1/S2 titers >80 AU/mL. Being tested from May-18 to June-5, or residing in the provinces with higher SARS-CoV-2 circulation, were positively and independently associated with anti-N IgG reactivity (OR [95%CI]: 2.179[1.455–3.264] and 3.127[1.18–8.29], respectively). In the 18 RT-PCR positive, symptomatic subjects, anti-N seroprevalence was 33.3% (95% CI: 14.8%-56.3%).
SARS-CoV-2 seroprevalence in Milan is low, and in a downward trend after only 60–63 days since the peak of diagnoses. Italian confinement measures were effective, but the risk of contagion remains concrete. In hospital-settings, the performance of molecular and serological screenings upon admission remains highly advisable.
Jingwen Li, Xinyi Wang, Chunli Zhu, Zhicheng Lin, Nian Xiong
Angeliki Melidou, Dmitriy Pereyaslov, Olav Hungnes, Katarina Prosenc, Erik Alm, Cornelia Adlhoch, James Fielding, Miriam Sneiderman, Oksana Martinuka, Lucia Pastore Celentano, Richard Pebody
The COVID-19 pandemic negatively impacted the 2019/20 WHO European Region influenza surveillance. Compared with previous 4-year averages, antigenic and genetic characterisations decreased by 17% (3,140 vs 2,601) and 24% (4,474 vs 3,403). Of subtyped influenza A viruses, 56% (26,477/47,357) were A(H1)pdm09, 44% (20,880/47,357) A(H3). Of characterised B viruses, 98% (4,585/4,679) were B/Victoria. Considerable numbers of viruses antigenically differed from northern hemisphere vaccine components. In 2020/21, maintaining influenza virological surveillance, while supporting SARS-CoV-2 surveillance is crucial.
Cathal Roarty, Claire Tonry, Lisa McFetridge, Hannah Mitchell, Chris Watson, Thomas Waterfield
ROYAL SOCIETY OPEN SCIENCE
Steven J. Phipps, R. Quentin Grafton, Tom Kompas
Differences in COVID-19 testing and tracing across countries, as well as changes in testing within each country over time, make it difficult to estimate the true (population) infection rate based on the confirmed number of cases obtained through RNA viral testing. We applied a backcasting approach to estimate a distribution for the true (population) cumulative number of infections (infected and recovered) for 15 developed countries. Our sample comprised countries with similar levels of medical care and with populations that have similar age distributions. Monte Carlo methods were used to robustly sample parameter uncertainty. We found a strong and statistically significant negative relationship between the proportion of the population who test positive and the implied true detection rate. Despite an overall improvement in detection rates as the pandemic has progressed, our estimates showed that, as at 31 August 2020, the true number of people to have been infected across our sample of 15 countries was 6.2 (95% CI: 4.3–10.9) times greater than the reported number of cases. In individual countries, the true number of cases exceeded the reported figure by factors that range from 2.6 (95% CI: 1.8–4.5) for South Korea to 17.5 (95% CI: 12.2–30.7) for Italy.
Davide Ferrari, Jovana Milic, Roberto Tonelli, Francesco Ghinelli, Marianna Meschiari, Sara Volpi, Matteo Faltoni, Giacomo Franceschi, Vittorio Iadisernia, Dina Yaacoub, Giacomo Ciusa, Erica Bacca, Carlotta Rogati, Marco Tutone, Giulia Burastero, Alessandro Raimondi, Marianna Menozzi, Erica Franceschini, Gianluca Cuomo, Luca Corradi, Gabriella Orlando, Antonella Santoro, Margherita Digaetano, Cinzia Puzzolante, Federica Carli, Vanni Borghi, Andrea Bedini, Riccardo Fantini, Luca Tabbì, Ivana Castaniere, Stefano Busani, Enrico Clini, Massimo Girardis, Mario Sarti, Andrea Cossarizza, Cristina Mussini, Federica Mandreoli, Paolo Missier , Giovanni Guaraldi
Giovanni Apolone, Emanuele Montomoli, Alessandro Manenti, Mattia Boeri, Federica Sabia, Inesa Hyseni, Livia Mazzini, Donata Martinuzzi, Laura Cantone, Gianluca Milanese, Stefano Sestini, Paola Suatoni, Alfonso Marchianò, Valentina Bollati, Gabriella Sozzi, Ugo Pastorino
There are no robust data on the real onset of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and spread in the prepandemic period worldwide. We investigated the presence of SARS-CoV-2 receptor-binding domain (RBD)–specific antibodies in blood samples of 959 asymptomatic individuals enrolled in a prospective lung cancer screening trial between September 2019 and March 2020 to track the date of onset, frequency, and temporal and geographic variations across the Italian regions. SARS-CoV-2 RBD-specific antibodies were detected in 111 of 959 (11.6%) individuals, starting from September 2019 (14%), with a cluster of positive cases (>30%) in the second week of February 2020 and the highest number (53.2%) in Lombardy. This study shows an unexpected very early circulation of SARS-CoV-2 among asymptomatic individuals in Italy several months before the first patient was identified, and clarifies the onset and spread of the coronavirus disease 2019 (COVID-19) pandemic. Finding SARS-CoV-2 antibodies in asymptomatic people before the COVID-19 outbreak in Italy may reshape the history of pandemic.
A.G. Letizia, I. Ramos, A. Obla, C. Goforth, D.L. Weir, Y. Ge, M.M. Bamman, J. Dutta, E. Ellis, L. Estrella, M.-C. George, A.S. Gonzalez-Reiche, W.D. Graham, A. van de Guchte, R. Gutierrez, F. Jones, A. Kalomoiri, R. Lizewski, S. Lizewski, J. Marayag, N. Marjanovic, E.V. Millar, V.D. Nair, G. Nudelman, E. Nunez, B.L. Pike, C. Porter, J. Regeimbal, S. Rirak, E. Santa Ana, R.S.G. Sealfon, R. Sebra, M.P. Simons, A. Soares-Schanoski, V. Sugiharto, M. Termini, S. Vangeti, C. Williams, O.G. Troyanskaya, H. van Bakel, S.C. Sealfon
The efficacy of public health measures to control the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has not been well studied in young adults.
We investigated SARS-CoV-2 infections among U.S. Marine Corps recruits who underwent a 2-week quarantine at home followed by a second supervised 2-week quarantine at a closed college campus that involved mask wearing, social distancing, and daily temperature and symptom monitoring. Study volunteers were tested for SARS-CoV-2 by means of quantitative polymerase-chain-reaction (qPCR) assay of nares swab specimens obtained between the time of arrival and the second day of supervised quarantine and on days 7 and 14. Recruits who did not volunteer for the study underwent qPCR testing only on day 14, at the end of the quarantine period. We performed phylogenetic analysis of viral genomes obtained from infected study volunteers to identify clusters and to assess the epidemiologic features of infections.
A total of 1848 recruits volunteered to participate in the study; within 2 days after arrival on campus, 16 (0.9%) tested positive for SARS-CoV-2, 15 of whom were asymptomatic. An additional 35 participants (1.9%) tested positive on day 7 or on day 14. Five of the 51 participants (9.8%) who tested positive at any time had symptoms in the week before a positive qPCR test. Of the recruits who declined to participate in the study, 26 (1.7%) of the 1554 recruits with available qPCR results tested positive on day 14. No SARS-CoV-2 infections were identified through clinical qPCR testing performed as a result of daily symptom monitoring. Analysis of 36 SARS-CoV-2 genomes obtained from 32 participants revealed six transmission clusters among 18 participants. Epidemiologic analysis supported multiple local transmission events, including transmission between roommates and among recruits within the same platoon.
Among Marine Corps recruits, approximately 2% who had previously had negative results for SARS-CoV-2 at the beginning of supervised quarantine, and less than 2% of recruits with unknown previous status, tested positive by day 14. Most recruits who tested positive were asymptomatic, and no infections were detected through daily symptom monitoring. Transmission clusters occurred within platoons. (Funded by the Defense Health Agency and others.)
Nelson L. Michael
Matthew R. Kasper, Jesse R. Geibe, Christine L. Sears, Asha J. Riegodedios, Tina Luse, Annette M. Von Thun, Michael B. McGinnis, Niels Olson, Daniel Houskamp, Robert Fenequito, Timothy H. Burgess, Adam W. Armstrong, Gerald DeLong, Robert J. Hawkins, Bruce L. Gillingham
An outbreak of coronavirus disease 2019 (Covid-19) occurred on the U.S.S. Theodore Roosevelt, a nuclear-powered aircraft carrier with a crew of 4779 personnel.
We obtained clinical and demographic data for all crew members, including results of testing by real-time reverse-transcriptase polymerase chain reaction (rRT-PCR). All crew members were followed up for a minimum of 10 weeks, regardless of test results or the absence of symptoms.
The crew was predominantly young (mean age, 27 years) and was in general good health, meeting U.S. Navy standards for sea duty. Over the course of the outbreak, 1271 crew members (26.6% of the crew) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by rRT-PCR testing, and more than 1000 infections were identified within 5 weeks after the first laboratory-confirmed infection. An additional 60 crew members had suspected Covid-19 (i.e., illness that met Council of State and Territorial Epidemiologists clinical criteria for Covid-19 without a positive test result). Among the crew members with laboratory-confirmed infection, 76.9% (978 of 1271) had no symptoms at the time that they tested positive and 55.0% had symptoms develop at any time during the clinical course. Among the 1331 crew members with suspected or confirmed Covid-19, 23 (1.7%) were hospitalized, 4 (0.3%) received intensive care, and 1 died. Crew members who worked in confined spaces appeared more likely to become infected.
SARS-CoV-2 spread quickly among the crew of the U.S.S. Theodore Roosevelt. Transmission was facilitated by close-quarters conditions and by asymptomatic and presymptomatic infected crew members. Nearly half of those who tested positive for the virus never had symptoms.
Alexander F. Siegenfeld, Yaneer Bar-Yam
While the spread of communicable diseases such as coronavirus disease 2019 (COVID-19) is often analyzed assuming a well-mixed population, more realistic models distinguish between transmission within and between geographic regions. A disease can be eliminated if the region-to-region reproductive number—i.e., the average number of other regions to which a single infected region will transmit the disease—is reduced to less than one. Here we show that this region-to-region reproductive number is proportional to the travel rate between regions and exponential in the length of the time-delay before region-level control measures are imposed. If, on average, infected regions (including those that become re-infected in the future) impose social distancing measures shortly after experiencing community transmission, the number of infected regions, and thus the number of regions in which such measures are required, will exponentially decrease over time. Elimination will in this case be a stable fixed point even after the social distancing measures have been lifted from most of the regions.
GOVERNMENT OF CANADA
Emerging Sciences Group of the Public Health Agency of Canada
Jennifer L. Taylor-Cousar, Lisa Maier, Gregory P. Downey, Michael E. Wechsler
The clinical research we do to improve our understanding of disease and development of new
therapies has temporarily been paused or delayed as the global healthcare enterprise has
focused its attention on those impacted by COVID-19. While rates of SARS-CoV-2 infection are
decreasing in many areas, many locations continue to have a high prevalence of infection.
Nonetheless, research must continue and institutions are considering approaches to re-starting
non-COVID related clinical investigation. Those restarting respiratory research must navigate
the added planning challenges that take into account outcome measures that require aerosol
generating procedures. Such procedures potentially increase risk of transmission of SARS-CoV2 to research staff, utilize limited personal protective equipment, and require conduct in negative
pressure rooms. One must also be prepared to address the potential for COVID-19 resurgence.
With research subject and staff safety and maintenance of clinical trial data integrity as the
guiding principles, here we review key considerations and suggest a step-wise approach for
resuming respiratory clinical research.
Young Sup Shin, Jun Young Lee, Soojin Noh, Yoonna Kwak, Sangeun Jeon, Sunoh Kwon, Young-hee Jin, Min Seong Jang, Seungtaek Kim, Jong Hwan Song, Hyoung Rae Kim, Chul Min Park