Epidemics最新文献

{"title":"A pair formation model with recovery: Application to mpox","authors":"Matthew I. Betti ,&nbsp;Lauren Farrell ,&nbsp;Jane Heffernan","doi":"10.1016/j.epidem.2023.100693","DOIUrl":"10.1016/j.epidem.2023.100693","url":null,"abstract":"<div><p>The current global outbreaks of mpox is a unique infectious disease in the way it seems to be transmitting: it has been observed to be highly concentrated in communities of men who have sex with men (MSM) through pair formation, and also provides long lasting immunity. This framework of mostly close, prolonged contact spreading a disease that admits immunity after infection is unlike similar infections which either offer little to no immunity post-infection or are lifelong infections. This creates the need for a new model framework that incorporates pair formation structure with recovery. While seemingly a straight forward model, we show how new dynamics arise from the combination of pair formation and recovery that are not present in a standard model with recovery and also not present in a pair formation model without recovery. We see that the combination of these two properties allows for waves of infection that are not seen in a standard SIR model. These dynamics suggest that outbreaks of mpox around the world may require special attention from public health. We also derive a reproduction number for this model and estimate the reproduction number of human mpox to be <span><math><mrow><mo>≈</mo><mn>2</mn><mo>.</mo><mn>3</mn></mrow></math></span> using global and Canadian data. The expression derived for <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> can help estimate key parameters for diseases transmission and public health interventions and compare to equivalent models without pair formation.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100693"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10530220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lives saved by public health restrictions over the Victorian COVID-19 Delta variant epidemic wave, Aug-Nov 2021","authors":"D. Delport ,&nbsp;R. Sacks-Davis ,&nbsp;R.G. Abeysuriya ,&nbsp;M. Hellard ,&nbsp;N. Scott","doi":"10.1016/j.epidem.2023.100702","DOIUrl":"10.1016/j.epidem.2023.100702","url":null,"abstract":"<div><h3>Background</h3><p>Prior to mid-2021, Australia’s approach to COVID-19 was to eliminate community transmission. However, between August-November 2021, the state of Victoria, Australia, experienced an outbreak of the Delta variant that continued to grow despite extensive lockdowns and public health measures in place. While these public health restrictions were ultimately unable to stop community transmission, they likely had a major impact reducing transmission and adverse health outcomes relative to voluntary risk-mitigation only (e.g., in response to rising cases and deaths, some people may avoid crowded settings, hospitality, retail, social occasions, or indoor settings). This study aims to estimate the impact of the August-November 2021 enforced public health restrictions in Victoria, compared to voluntary risk-mitigation only.</p></div><div><h3>Methods</h3><p>An agent-based model was calibrated to Victorian epidemiological, health and behavioural data from 1 August to 30 November 2021, as well as policies that were implemented over that period. Two counter-factual scenarios were run for the same period with (a) no restrictions in place; or (b) voluntary risk-mitigation only, based on behaviour measured over the December-January Omicron BA.1 epidemic wave when restrictions were not in place.</p></div><div><h3>Results</h3><p>Over August-November 2021, the baseline model scenario resulted in 97,000 (91,000−102,000) diagnoses, 9100 (8500−9700) hospital admissions, and 480 (430−530) deaths. Without any restrictions in place, there were 3,228,000 (3,200,000−3,253,000) diagnoses, 375,100 (370,200−380,900) hospital admissions, and 16,700 (16,000−17,500) deaths. With voluntary risk-mitigation equal to those observed during the Omicron BA.1 epidemic wave, there were 1,507,000 (1,469,000−1,549,000) diagnoses, 130,300 (124,500−136,000) hospital admissions, and 5500 (5000−6100) deaths.</p></div><div><h3>Conclusion</h3><p>Public health restrictions implemented in Victoria over August-November 2021 are likely to have averted more than 120,000 hospitalizations and 5000 deaths relative to voluntary risk-mitigation only. During a COVID-19 epidemic wave voluntary behaviour change can reduce transmission substantially, but not to the same extent as enforced restrictions.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100702"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10265399/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10547706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epidemiological characteristics and transmissibility of HPV infection: A long-term retrospective study in Hokkien Golden Triangle, China, 2013–2021","authors":"Jingwen Xu ,&nbsp;Guzainuer Abudurusuli ,&nbsp;Jia Rui ,&nbsp;Zhuoyang Li ,&nbsp;Zeyu Zhao ,&nbsp;Yilan Xia ,&nbsp;Xiaohao Guo ,&nbsp;Buasiyamu Abudunaibi ,&nbsp;Benhua Zhao ,&nbsp;Qiwei Guo ,&nbsp;Jing-An Cui ,&nbsp;Yulin Zhou ,&nbsp;Tianmu Chen","doi":"10.1016/j.epidem.2023.100707","DOIUrl":"10.1016/j.epidem.2023.100707","url":null,"abstract":"<div><h3>Objective</h3><p>Multiple human papillomavirus (HPV)-associated diseases have put a significant disease burden on the world. Therefore, we conducted a study to explore the epidemiological characteristics of HPV and the transmissibility of its genotypes.</p></div><div><h3>Methods</h3><p>HPV testing data was collected from Hospital. A transmission dynamics model of HPV was constructed to simulate and compare the transmissibility of different HPV genotypes, which was quantitatively described by the basic reproduction number (<em>R</em>₀).</p></div><div><h3>Results</h3><p>The collected HPV subjects were mainly from Xiamen City, Zhangzhou City and Quanzhou City, together, they are known as the Hokkien golden triangle. There were variations in the distribution of HPV infections by age groups. Among all HPV genotypes, 13 of them had <em>R</em>₀ &gt; 1, with 10 of them being high-risk types. The top five were HPV56, 18, 58, 52 and 53, among which, HPV56, 18, 58 and 42 were of high risk, whereas HPV53 was not, and the <em>R</em>₀ values for the five were 3.35 (CI: 0.00–9.99), 3.20 (CI: 0.00–6.46), 3.19 (CI: 1.27–6.94), 3.19 (CI: 1.01–8.42) and 2.99 (CI: 0.00–9.39), respectively. In addition, HPV52 had <em>R</em>₀ &gt; 1 for about 51 months, which had the longest duration.</p></div><div><h3>Conclusion</h3><p>Most high-risk HPV types in the Hokkien golden triangle could transmit among the population. Therefore, there is a need of further optimization for developing HPV vaccines and better detection methods in the region.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100707"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10233942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SARS-CoV-2 transmission patterns in educational settings during the Alpha wave in Reggio-Emilia, Italy","authors":"Carla Molina Grané ,&nbsp;Pamela Mancuso ,&nbsp;Massimo Vicentini ,&nbsp;Francesco Venturelli ,&nbsp;Olivera Djuric ,&nbsp;Mattia Manica ,&nbsp;Giorgio Guzzetta ,&nbsp;Valentina Marziano ,&nbsp;Agnese Zardini ,&nbsp;Valeria d’Andrea ,&nbsp;Filippo Trentini ,&nbsp;Eufemia Bisaccia ,&nbsp;Elisabetta Larosa ,&nbsp;Silvia Cilloni ,&nbsp;Maria Teresa Cassinadri ,&nbsp;Patrizio Pezzotti ,&nbsp;Marco Ajelli ,&nbsp;Paolo Giorgi Rossi ,&nbsp;Stefano Merler ,&nbsp;Piero Poletti","doi":"10.1016/j.epidem.2023.100712","DOIUrl":"10.1016/j.epidem.2023.100712","url":null,"abstract":"<div><p>Different monitoring and control policies have been implemented in schools to minimize the spread of SARS-CoV-2. Transmission in schools has been hard to quantify due to the large proportion of asymptomatic carriers in young individuals. We applied a Bayesian approach to reconstruct the transmission chains between 284 SARS-CoV-2 infections ascertained during 87 school outbreak investigations conducted between March and April 2021 in Italy. Under the policy of reactive quarantines, we found that 42.5% (95%CrI: 29.5–54.3%) of infections among school attendees were caused by school contacts. The mean number of secondary cases infected at school by a positive individual during in-person education was estimated to be 0.33 (95%CrI: 0.23–0.43), with marked heterogeneity across individuals. Specifically, we estimated that only 26.0% (95%CrI: 17.6–34.1%) of students and school personnel who tested positive during in-person education caused at least one secondary infection at school. Positive individuals who attended school for at least 6 days before being isolated or quarantined infected on average 0.49 (95%CrI: 0.14–0.83) secondary cases. Our findings provide quantitative insights on the contribution of school transmission to the spread of SARS-CoV-2 in young individuals. Identifying positive cases within 5 days after exposure to their infector could reduce onward transmission at school by at least 30%.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100712"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10234494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A model for malaria treatment evaluation in the presence of multiple species","authors":"C.R. Walker ,&nbsp;R.I. Hickson ,&nbsp;E. Chang ,&nbsp;P. Ngor ,&nbsp;S. Sovannaroth ,&nbsp;J.A. Simpson ,&nbsp;D.J. Price ,&nbsp;J.M. McCaw ,&nbsp;R.N. Price ,&nbsp;J.A. Flegg ,&nbsp;A. Devine","doi":"10.1016/j.epidem.2023.100687","DOIUrl":"10.1016/j.epidem.2023.100687","url":null,"abstract":"<div><p>Plasmodium <em>falciparum</em> and <em>P. vivax</em> are the two most common causes of malaria. While the majority of deaths and severe morbidity are due to <em>P. falciparum</em>, <em>P. vivax</em> poses a greater challenge to eliminating malaria outside of Africa due to its ability to form latent liver stage parasites (hypnozoites), which can cause relapsing episodes within an individual patient. In areas where <em>P. falciparum</em> and <em>P. vivax</em> are co-endemic, individuals can carry parasites of both species simultaneously. These mixed infections complicate dynamics in several ways: treatment of mixed infections will simultaneously affect both species, <em>P. falciparum</em> can mask the detection of <em>P. vivax</em>, and it has been hypothesised that clearing <em>P. falciparum</em> may trigger a relapse of dormant <em>P. vivax</em>. When mixed infections are treated for only blood-stage parasites, patients are at risk of relapse infections due to <em>P. vivax</em> hypnozoites.</p><p>We present a stochastic mathematical model that captures interactions between <em>P. falciparum</em> and <em>P. vivax</em>, and incorporates both standard schizonticidal treatment (which targets blood-stage parasites) and radical cure treatment (which additionally targets liver-stage parasites). We apply this model via a hypothetical simulation study to assess the implications of different treatment coverages of radical cure for mixed and <em>P. vivax</em> infections and a “unified radical cure” treatment strategy where <em>P. falciparum</em>, <em>P. vivax</em>, and mixed infections all receive radical cure after screening glucose-6-phosphate dehydrogenase (G6PD) normal. In addition, we investigated the impact of mass drug administration (MDA) of blood-stage treatment. We find that a unified radical cure strategy leads to a substantially lower incidence of malaria cases and deaths overall. MDA with schizonticidal treatment was found to decrease <em>P. falciparum</em> with little effect on <em>P. vivax</em>. We perform a univariate sensitivity analysis to highlight important model parameters.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100687"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/f9/43/EMS181722.PMC7614843.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10530221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the impact of different PrEP targeting strategies combined with a clinic-based HIV-1 nucleic acid testing intervention in Kenya","authors":"Deven T. Hamilton ,&nbsp;Clara Agutu ,&nbsp;Martin Sirengo ,&nbsp;Wairimu Chege ,&nbsp;Steven M. Goodreau ,&nbsp;Adam Elder ,&nbsp;Eduard J. Sanders ,&nbsp;Susan M. Graham","doi":"10.1016/j.epidem.2023.100696","DOIUrl":"10.1016/j.epidem.2023.100696","url":null,"abstract":"<div><h3>Background</h3><p>Up to 69% of adults who acquire HIV in Kenya seek care for acute retroviral symptoms, providing an important opportunity for early diagnosis and HIV care engagement. The Tambua Mapema Plus (TMP) trial tested a combined HIV-1 nucleic acid testing, linkage, treatment, and partner notification intervention for adults with symptoms of acute HIV infection presenting to health facilities in coastal Kenya. We estimated the potential impact on the Kenyan HIV epidemic of providing PrEP to individuals testing negative in TMP, if scaled up.</p></div><div><h3>Methods</h3><p>We developed an agent-based simulation of HIV-1 transmission using TMP data and current Kenyan statistics. PrEP interventions were layered onto a model of TMP as standard of care, to estimate additional potential population-level impact of enrolling HIV-negative individuals identified through TMP on PrEP over 10 years. Four scenarios were modeled: PrEP for uninfected individuals in disclosed serodiscordant couples; PrEP for individuals with concurrent partnerships; PrEP for all uninfected individuals identified through TMP; and PrEP integrated into the enhanced partner services component of TMP.</p></div><div><h3>Findings</h3><p>Providing PrEP to both individuals with concurrent partnerships and uninfected partners identified through enhanced partner services reduced new HIV infections and was efficient based on numbers needed to treat (NNT). The mean percent of infections averted was 2.79 (95%SI:−10.83, 15.24) and 4.62 (95%SI:−9.5, 16.82) when PrEP uptake was 50% and 100%, respectively, and median NNT was 22.54 (95%SI:not defined, 6.45) and 27.55 (95%SI:not defined, 11.0), respectively. Providing PrEP for all uninfected individuals identified through TMP averted up to 12.68% (95%SI:0.17, 25.19) of new infections but was not efficient based on the NNT: 200.24 (95%SI:523.81, 123.23).</p></div><div><h3>Conclusions</h3><p>Providing PrEP to individuals testing negative for HIV-1 nucleic acid after presenting to a health facility with symptoms compatible with acute HIV adds value to the TMP intervention, provided PrEP is targeted effectively and efficiently.</p></div><div><h3>Funding</h3><p>National Institutes of Health, Sub-Saharan African Network for TB/HIV Research Excellence.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100696"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10529734/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10176578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The aquaculture disease network model (AquaNet-Mod): A simulation model to evaluate disease spread and controls for the salmonid industry in England and Wales","authors":"James Guilder,&nbsp;David Ryder,&nbsp;Nick G.H. Taylor,&nbsp;Sarah R. Alewijnse,&nbsp;Rebecca S. Millard,&nbsp;Mark A. Thrush,&nbsp;Edmund J. Peeler,&nbsp;Hannah J. Tidbury","doi":"10.1016/j.epidem.2023.100711","DOIUrl":"10.1016/j.epidem.2023.100711","url":null,"abstract":"<div><p>Infectious disease causes significant mortality in wild and farmed systems, threatening biodiversity, conservation and animal welfare, as well as food security. To mitigate impacts and inform policy, tools such as mathematical models and computer simulations are valuable for predicting the potential spread and impact of disease. This paper describes the development of the Aquaculture Disease Network Model, AquaNet-Mod, and demonstrates its application to evaluating disease epidemics and the efficacy of control, using a Viral Haemorrhagic Septicaemia (VHS) case study. AquaNet-Mod is a data-driven, stochastic, state-transition model. Disease spread can occur via four different mechanisms, i) live fish movement, ii) river based, iii) short distance mechanical and iv) distance independent mechanical. Sites transit between three disease states: susceptible, clinically infected and subclinically infected. Disease spread can be interrupted by the application of disease mitigation measures and controls such as contact tracing, culling, fallowing and surveillance. Results from a VHS case study highlight the potential for VHS to spread to 96% of sites over a 10 year time horizon if no disease controls are applied. Epidemiological impact is significantly reduced when live fish movement restrictions are placed on the most connected sites and further still, when disease controls, representative of current disease control policy in England and Wales, are applied. The importance of specific disease control measures, particularly contact tracing and disease detection rate, are also highlighted. The merit of this model for evaluation of disease spread and the efficacy of controls, in the context of policy, along with potential for further application and development of the model, for example to include economic parameters, is discussed.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100711"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10180737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association between pertussis vaccination coverage and other sociodemographic factors and pertussis incidence using surveillance data","authors":"Madhura S. Rane ,&nbsp;Jonathan Wakefield ,&nbsp;Pejman Rohani ,&nbsp;M. Elizabeth Halloran","doi":"10.1016/j.epidem.2023.100689","DOIUrl":"10.1016/j.epidem.2023.100689","url":null,"abstract":"<div><p>Routine vaccination with pertussis vaccines has been successful in driving down pertussis mortality and morbidity globally. Despite high vaccination coverage, countries such as Australia, USA, and UK have experienced increase in pertussis activity over the last few decades. This may be due to local pockets of low vaccination coverage that result in persistence of pertussis in the population and occasionally lead to large outbreaks. The objective of this study was to characterize the association between pertussis vaccination coverage and sociodemographic factors and pertussis incidence at the school district level in King County, Washington, USA. We used monthly pertussis incidence data for all ages reported to the Public Health Seattle and King County between January 1, 2010 and December 31, 2017 to obtain school district level pertussis incidence. We obtained immunization data from the Washington State Immunization Information System to estimate school-district level vaccination coverage as proportion of 19–35 month old children fully vaccinated with <span><math><mo>≥</mo></math></span>4 doses of the Diphtheria-Tetanus-acellular-Pertussis (DTaP) vaccine in a school district. We used two methods to quantify the effects of vaccination coverage on pertussis incidence: an ecological vaccine model and an endemic–epidemic model. Even though the effect of vaccination is modeled differently in the two approaches, both models can be used to estimate the association between vaccination coverage and pertussis incidence. Using the ecological vaccine model, we estimated the vaccine effectiveness of 4 doses of Diphtheria-Tetanus-acellular-Pertussis vaccine to be 83% (95% credible interval: 63%, 95%). In the endemic–epidemic model, under-vaccination was statistically significantly associated with epidemic risk of pertussis (adjusted Relative Risk, aRR: 2.76; 95% confidence interval: 1.44, 16.6). Household size and median income were statistically significantly associated with endemic pertussis risk. The endemic–epidemic model suffers from ecological bias, whereas the ecological vaccine model provides less biased and more interpretable estimates of epidemiological parameters, such as DTaP vaccine effectiveness, for each school district.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100689"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10584035/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10174584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of SARS-CoV-2 outbreaks in a primary school using epidemiological and genomic data","authors":"Cécile Kremer ,&nbsp;Andrea Torneri ,&nbsp;Pieter J.K. Libin ,&nbsp;Cécile Meex ,&nbsp;Marie-Pierre Hayette ,&nbsp;Sébastien Bontems ,&nbsp;Keith Durkin ,&nbsp;Maria Artesi ,&nbsp;Vincent Bours ,&nbsp;Philippe Lemey ,&nbsp;Gilles Darcis ,&nbsp;Niel Hens ,&nbsp;Christelle Meuris","doi":"10.1016/j.epidem.2023.100701","DOIUrl":"10.1016/j.epidem.2023.100701","url":null,"abstract":"<div><p>Mathematical modelling studies have shown that repetitive screening can be used to mitigate SARS-CoV-2 transmission in primary schools while keeping schools open. However, not much is known about how transmission progresses within schools and whether there is a risk of importation to households. During the academic year 2020–2021, a prospective surveillance study using repetitive screening was conducted in a primary school and associated households in Liège (Belgium). SARS-CoV-2 screening was performed via throat washing either once or twice a week. We used genomic and epidemiological data to reconstruct the observed school outbreaks using two different models. The outbreaker2 model combines information on the generation time and contact patterns with a model of sequence evolution. For comparison we also used SCOTTI, a phylogenetic model based on the structured coalescent. In addition, we performed a simulation study to investigate how the accuracy of estimated positivity rates in a school depends on the proportion of a school that is sampled in a repetitive screening strategy. We found no difference in SARS-CoV-2 positivity between children and adults and children were not more often asymptomatic compared to adults. Both models for outbreak reconstruction revealed that transmission occurred mainly within the school environment. Uncertainty in outbreak reconstruction was lowest when including genomic as well as epidemiological data. We found that observed weekly positivity rates are a good approximation to the true weekly positivity rate, especially in children, even when only 25% of the school population is sampled. These results indicate that, in addition to reducing infections as shown in modelling studies, repetitive screening in school settings can lead to a better understanding of the extent of transmission in schools during a pandemic and importation risk at the community level.</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100701"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10273772/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10177939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymptomatic but infectious – The silent driver of pathogen transmission. A pragmatic review","authors":"Nabila Shaikh ,&nbsp;Pooja Swali ,&nbsp;Rein M.G.J. Houben","doi":"10.1016/j.epidem.2023.100704","DOIUrl":"10.1016/j.epidem.2023.100704","url":null,"abstract":"<div><p>Throughout 2020, COVID-19 interventions prioritised symptomatic individuals despite growing evidence of pre-symptomatic and asymptomatic transmission. From the pandemic we have learned that global health is slow to quantify asymptomatic disease transmission and slow to implement relevant interventions. While asymptomatic infectious periods exist for nearly all pathogens, it is frequently ignored during case finding, and there are limited research efforts to understand its potential to drive small scale outbreaks, epidemics and pandemics. We conducted a pragmatic review on 15 key pathogens including SARS-CoV-2 and Ebola to demonstrate substantial variation in terminology around asymptomatic infectious individuals, and varying proportions of asymptomatic amongst prevalent infectious cases (0–99 %) and their contribution to transmission (0–96 %). While no pattern was discernible by pathogen type (virus, bacteria, parasite) or mode of transmission (direct, indirect or mixed), there are multiple lessons to learn from previous and current control programmes. As found during the COVID-19 pandemic, overlooking asymptomatic infectious individuals can impede disease control. Improving our understanding of how asymptomatic individuals can drive epidemics can strengthen our efforts to control current pathogens, and improve our preparedness for when the next new pathogen emerges..</p></div>","PeriodicalId":49206,"journal":{"name":"Epidemics","volume":"44 ","pages":"Article 100704"},"PeriodicalIF":3.8,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10260263/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10177970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}