scholarly journals Within and between classroom transmission patterns of seasonal influenza among primary school students in Matsumoto city, Japan

2021 ◽  
Author(s):  
Akira Endo ◽  
Mitsuo Uchida ◽  
Naoki Hayashi ◽  
Yang Liu ◽  
Katherine E Atkins ◽  
...  
Keyword(s):  
Large Scale ◽  
Seasonal Influenza ◽  
Reproduction Number ◽  
Respiratory Infections ◽  
Social Contact ◽  
Initial Growth ◽  
School Students ◽  
Relative Contribution ◽  
Contact Patterns ◽  
Number Of Classes

Schools play a central role in the transmission of many respiratory infections. Heterogeneous social contact patterns associated with the social structures of schools (i.e. classes/grades) are likely to influence the within-school transmission dynamics, but data-driven evidence on fine-scale transmission patterns between students has been limited. Using a mathematical model, we analysed a large-scale dataset of seasonal influenza outbreaks in Matsumoto city, Japan to infer social interactions within and between classes/grades from observed transmission patterns. While the relative contribution of within-class and within-grade transmissions to the reproduction number varied with the number of classes per grade, tThe overall within-school reproduction number, which determines the initial growth of cases and the risk of sustained transmission, was only minimally associated with class sizes and the number of classes per grade. This finding suggests that interventions that change the size and number of classes, e.g. splitting classes and staggered attendance, may have limited effect on the control of school outbreaks. We also found that vaccination and mask-wearing of students were associated with reduced susceptibility (vaccination and mask-wearing) and infectiousness (mask-wearing) and hand washing with increased susceptibility. Our results show how analysis of fine-grained transmission patterns between students can improve understanding of within-school disease dynamics and provide insights into the relative impact of different approaches to outbreak control.

scholarly journals Within and between classroom transmission patterns of seasonal influenza among primary school students in Matsumoto city, Japan

2021 ◽  
Vol 118 (46) ◽  
pp. e2112605118
Author(s):  
Akira Endo ◽  
Mitsuo Uchida ◽  
Naoki Hayashi ◽  
Yang Liu ◽  
Katherine E. Atkins ◽  
...  
Keyword(s):  
Large Scale ◽  
Seasonal Influenza ◽  
Reproduction Number ◽  
Respiratory Infections ◽  
Social Contact ◽  
Initial Growth ◽  
School Students ◽  
Relative Contribution ◽  
Contact Patterns ◽  
Number Of Classes

Schools play a central role in the transmission of many respiratory infections. Heterogeneous social contact patterns associated with the social structures of schools (i.e., classes/grades) are likely to influence the within-school transmission dynamics, but data-driven evidence on fine-scale transmission patterns between students has been limited. Using a mathematical model, we analyzed a large-scale dataset of seasonal influenza outbreaks in Matsumoto city, Japan, to infer social interactions within and between classes/grades from observed transmission patterns. While the relative contribution of within-class and within-grade transmissions to the reproduction number varied with the number of classes per grade, the overall within-school reproduction number, which determines the initial growth of cases and the risk of sustained transmission, was only minimally associated with class sizes and the number of classes per grade. This finding suggests that interventions that change the size and number of classes, e.g., splitting classes and staggered attendance, may have a limited effect on the control of school outbreaks. We also found that vaccination and mask-wearing of students were associated with reduced susceptibility (vaccination and mask-wearing) and infectiousness (mask-wearing), and hand washing was associated with increased susceptibility. Our results show how analysis of fine-grained transmission patterns between students can improve understanding of within-school disease dynamics and provide insights into the relative impact of different approaches to outbreak control.

scholarly journals Investigating the relationship between interventions, contact patterns, and SARS-CoV-2 transmissibility

2021 ◽  
Author(s):  
Filippo Trentini ◽  
Adriana Manna ◽  
Nicoletta Balbo ◽  
Valentina Marziano ◽  
Giorgio Guzzetta ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Reproduction Number ◽  
Social Contact ◽  
Negative Binomial Regression ◽  
Transmission Potential ◽  
Relative Contribution ◽  
Contact Patterns ◽  
Italian Regions ◽  
Mixing Patterns ◽  
The Government

Background After a rapid upsurge of COVID-19 cases in Italy during the fall of 2020, the government introduced a three-tiered restriction system aimed at increasing physical distancing. The Ministry of Health, after periodic epidemiological risk assessments, assigned a tier to each of the 21 Italian regions and autonomous provinces (AP). It is still unclear to what extent these different measures altered mixing patterns and how quickly the population adapted their social interactions to continuous changes in restrictions. Methods and findings We conducted a survey between July 2020 and March 2021 to monitor changes in social contact patterns among individuals in the metropolitan city of Milan, Italy, which was hardly hit by the second wave of COVID-19 pandemic. The number of contacts during periods characterized by different levels of restrictions was analyzed through negative binomial regression models and age-specific contact matrices were estimated under the different tiers. Relying on the empirically estimated mixing patterns, we quantified relative changes in SARS-CoV-2 transmission potential associated with the different tiers. As tighter restrictions were implemented during the fall of 2020, a progressive reduction in the mean number of contacts recorded by study participants was observed: from 16.4% under mild restrictions (yellow tier), to 45.6% under strong restrictions (red tier). Higher restrictions levels were also found to increase the relative contribution of contacts occurring within the household. The SARS-CoV-2 reproduction number was estimated to decrease by 18.7% (95%CI: 4.6-30.8), 33.4% (95%CI: 22.7-43.2), and 50.2% (95%CI: 40.9-57.7) under the yellow, orange, and red tiers, respectively. Conclusions Our results give an important quantification of the expected contribution of different restriction levels in shaping social contacts and decreasing the transmission potential of SARS-CoV-2. These estimates can find an operational use in anticipating the effect that the implementation of these tiered restriction can have on SARS-CoV-2 reproduction number under an evolving epidemiological situation.

scholarly journals Within and between classroom transmission patterns of seasonal influenza and implications for pandemic management strategies at schools

2021 ◽  
Author(s):  
Akira Endo ◽  
Mitsuo Uchida ◽  
Yang Liu ◽  
Katherine Atkins ◽  
Adam Kucharski ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Large Scale ◽  
Seasonal Influenza ◽  
Management Strategies ◽  
Social Contact ◽  
Screening Tests ◽  
Initial Growth ◽  
Precautionary Measures ◽  
Reduced Class Sizes ◽  
The Impact

Abstract Schools can play a central role in driving infectious disease transmission. Strategies for safe operation of schools during pandemics therefore need to carefully consider both the efficiency of measures for infection control and the impact on children through lost face-to face schooling time. Heterogeneous social contact patterns associated with the social structures of schools (i.e. classes/grades) are likely to influence the within-school transmission dynamics; however, empirical evidence on the fine-scale transmission patterns between students has been limited. Using a mathematical model, we analysed a large-scale dataset of seasonal influenza outbreaks in Matsumoto city, Japan to infer social interactions within and between classes/grades from observed transmission patterns. The overall within-school reproduction number, which determines the initial growth of cases and the risk of sustained transmission, was only minimally associated with class sizes and the number of classes per grade. We then used these patterns in a model parameterised separately to COVID-19 and pandemic influenza, and simulated school outbreaks under multiple strategies for minimising the risk of within-school transmission. Simulations suggested that with such transmission patterns, interventions changing class structures (e.g. reduced class sizes) may not be effective in reducing the risk of major school outbreaks upon introduction of a case and that other precautionary measures (e.g. screening and isolation) need to be employed. Class-level closures in response to detection of a case were suggested to be effective in reducing the size of an outbreak when regular screening tests for students are not available.

scholarly journals Study design and protocol for investigating social network patterns in rural and urban schools and households in a coastal setting in Kenya using wearable proximity sensors

2019 ◽  
Vol 4 ◽  
pp. 84 ◽  
Author(s):  
Moses Chapa Kiti ◽  
Alessia Melegaro ◽  
Ciro Cattuto ◽  
David James Nokes
Keyword(s):  
Urban Areas ◽  
Respiratory Infections ◽  
Social Contact ◽  
Simulation Models ◽  
Face To Face ◽  
Rural And Urban Areas ◽  
Contact Patterns ◽  
Rural And Urban ◽  
Syncytial Virus ◽  
The Impact

Background: Social contact patterns shape the transmission of respiratory infections spread via close interactions. There is a paucity of observational data from schools and households, particularly in developing countries. Portable wireless sensors can record unbiased proximity events between individuals facing each other, shedding light on pathways of infection transmission. Design and methods: The aim is to characterize face-to-face contact patterns that may shape the transmission of respiratory infections in schools and households in Kilifi, Kenya. Two schools, one each from a rural and urban area, will be purposively selected. From each school, 350 students will be randomly selected proportional to class size and gender to participate. Nine index students from each school will be randomly selected and followed-up to their households. All index household residents will be recruited into the study. A further 3-5 neighbouring households will also be recruited to give a maximum of 350 participants per household setting. The sample size per site is limited by the number of sensors available for data collection. Each participant will wear a wireless proximity sensor lying on their chest area for 7 consecutive days. Data on proximal dyadic interactions will be collected automatically by the sensors only for participants who are face-to-face. Key characteristics of interest include the distribution of degree and the frequency and duration of contacts and their variation in rural and urban areas. These will be stratified by age, gender, role, and day of the week. Expected results: Resultant data will inform on social contact patterns in rural and urban areas of a previously unstudied population. Ensuing data will be used to parameterize mathematical simulation models of transmission of a range of respiratory viruses, including respiratory syncytial virus, and used to explore the impact of intervention measures such as vaccination and social distancing.

scholarly journals Prospective Diary Survey of Preschool Children's Social Contact Patterns: A Pilot Study

2020 ◽  
Vol 26 (4) ◽  
pp. 393-401
Author(s):  
Hyang Soon Oh ◽  
Mikyung Ryu
Keyword(s):  
Pilot Study ◽  
Regression Model ◽  
Large Scale ◽  
Social Contact ◽  
Multiple Regression Model ◽  
Childcare Centers ◽  
Social Contacts ◽  
Significant Relationships ◽  
Contact Patterns ◽  
Day Of The Week

Purpose: This pilot study aimed to describe children's social contact patterns and to analyze factors related to their social contacts.Methods: The participants were 30 children aged ≥13 months to <7 years, whose teachers at childcare centers and parents at home were asked to maintain diaries of their social contacts prospectively for 24 hours. Data were collected from November 30, 2018, to January 7, 2019.Results: The 30 participating children were in contact with 363 persons in a 24-hours period (mean, 12.1±9.1). The number of contacts showed significant relationships with day of the week (p<.001), number of family members/cohabitants (p=.015), area of residence (p=.003), and type of housing (p=.002). A multiple regression model showed significantly higher numbers of contacts on weekdays (B=10.64, p=.010). Physical versus non-physical types of contact showed significant differences in terms of duration, location, and frequency (p<.001). The duration of contacts showed significant relationships with their location and frequency (p<.001), while the frequency of contacts was significantly related to their location (p<.001).Conclusion: This is the first survey describing the characteristics of Korean preschool children's social contacts. Further large-scale social contact studies of children should be conducted.

scholarly journals Close contact infection dynamics over time: insights from a second large-scale social contact survey in Flanders, Belgium, in 2010-2011

2020 ◽  
Author(s):  
Thang Van Hoang ◽  
Pietro Coletti ◽  
Yimer Wasihun Kiffe ◽  
Kim Van Kerckhove ◽  
Sarah Vercruysse ◽  
...  
Keyword(s):  
Large Scale ◽  
Close Contact ◽  
Social Contact ◽  
Contact Rates ◽  
Contact Patterns ◽  
Time Period ◽  
Social Mixing ◽  
Mixing Patterns ◽  
Contact Survey ◽  
The Impact

AbstractBackgroundIn 2010-2011, we conducted a social contact survey in Flanders, Belgium, aimed at improving and extending the design of the first social contact survey conducted in Belgium in 2006. This second social contact survey aimed to enable, for the first time, the estimation of social mixing patterns for an age range of 0 to 99 years and the investigation of whether contact rates remain stable over this 5-year time period.MethodsDifferent data mining techniques are used to explore the data, and the age-specific number of social contacts and the age-specific contact rates are modelled using a GAMLSS model. We compare different matrices using assortativeness measures. The relative change in the basic reproduction number (R0) and the ratio of relative incidences with 95% bootstrap confidence intervals (BCI) are employed to investigate and quantify the impact on epidemic spread due to differences in gender, day of the week, holiday vs. regular periods and changes in mixing patterns over the 5-year time gap between the 2006 and 2010-2011 surveys. Finally, we compare the fit of the contact matrices in 2006 and 2010-2011 to Varicella serological data.ResultsAll estimated contact patterns featured strong homophily in age and gender, especially for small children and adolescents. A 30% (95% BCI [17%; 37%] ) and 29% (95% BCI [14%; 40%] ) reduction in R0 was observed for weekend versus weekdays and for holiday versus regular periods, respectively. Significantly more interactions between people aged 60+ years and their grandchildren were observed on holiday and weekend days than on regular weekdays. Comparing contact patterns using different methods did not show any substantial differences over the 5-year time period under study.ConclusionsThe second social contact survey in Flanders, Belgium, endorses the findings of its 2006 predecessor and adds important information on the social mixing patterns of people older than 60 years of age. Based on this analysis, the mixing patterns of people older than 60 years exhibit considerable heterogeneity, and overall, the comparison of the two surveys shows that social contact rates can be assumed stable in Flanders over a time span of 5 years.

scholarly journals Study design and protocol for investigating social network patterns in rural and urban schools and households in a coastal setting in Kenya using wearable proximity sensors

2019 ◽  
Vol 4 ◽  
pp. 84 ◽  
Author(s):  
Moses Chapa Kiti ◽  
Alessia Melegaro ◽  
Ciro Cattuto ◽  
David James Nokes
Keyword(s):  
Urban Areas ◽  
Respiratory Infections ◽  
Social Contact ◽  
Simulation Models ◽  
Face To Face ◽  
Rural And Urban Areas ◽  
Contact Patterns ◽  
Rural And Urban ◽  
Syncytial Virus ◽  
The Impact

Background: Social contact patterns shape the transmission of respiratory infections spread via close interactions. There is a paucity of observational data from schools and households, particularly in developing countries. Portable wireless sensors can record unbiased proximity events between individuals facing each other, shedding light on pathways of infection transmission. Design and methods: The aim is to characterize face-to-face contact patterns that may shape the transmission of respiratory infections in schools and households in Kilifi, Kenya. Two schools, one each from a rural and urban area, will be purposively selected. From each school, 350 students will be randomly selected proportional to class size and gender to participate. Nine index students from each school will be randomly selected and followed-up to their households. All index household residents will be recruited into the study. A further 3-5 neighbouring households will also be recruited to give a maximum of 350 participants per household setting. The sample size per site is limited by the number of sensors available for data collection. Each participant will wear a wireless proximity sensor lying on their chest area for 7 consecutive days. Data on proximal dyadic interactions will be collected automatically by the sensors only for participants who are face-to-face. Key characteristics of interest include the distribution of degree and the frequency and duration of contacts and their variation in rural and urban areas. These will be stratified by age, gender, role, and day of the week. Expected results: Resultant data will inform on social contact patterns in rural and urban areas of a previously unstudied population. Ensuing data will be used to parameterize mathematical simulation models of transmission of a range of respiratory viruses, including respiratory syncytial virus, and used to explore the impact of intervention measures such as vaccination and social distancing.

scholarly journals Rapid review of social contact patterns during the COVID-19 pandemic

2021 ◽  
Author(s):  
Carol Y. Liu ◽  
Juliette Berlin ◽  
Moses C. Kiti ◽  
Emanuele Del Fava ◽  
André Grow ◽  
...  
Keyword(s):  
Respiratory Infections ◽  
Substantial Reduction ◽  
Social Contact ◽  
Rapid Review ◽  
Human Contact ◽  
Contact Rates ◽  
Contact Patterns ◽  
Working Age ◽  
Key Driver ◽  
Meta Analyses

AbstractBackgroundPhysical distancing measures aim to reduce person-to-person contact, a key driver of transmission of respiratory infections such as SARS-CoV-2. In response to unprecedented restrictions on human contact during the COVID-19 pandemic, a number of studies measured social contact patterns under the implementation of physical distancing measures. This rapid review aims to synthesize empirical data on the changing social contact patterns during the COVID-19 pandemic.MethodWe conducted a systematic review using PubMed, Medline, Embase and Google Scholar following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We descriptively compared the distribution of contacts observed during the pandemic to pre-COVID data across countries to explore changes in contact patterns during physical distancing measures.ResultsWe identified 12 studies that reported social contact patterns during the COVID-19 pandemic. The majority of studies (11/12) collected data during the initial mitigation period in the spring of 2020 marked by government-declared lockdowns and the most stringent physical distancing measures. Some studies collected additional data after relaxation of initial mitigation. Most study settings reported a mean of between 2-5 contacts per person per day, a substantial reduction compared to pre-COVID rates which ranged from 7-26 contacts per day in similar settings. This reduction was particularly pronounced for contacts outside of the home. Consequently, levels of assortative mixing by age substantially declined. After relaxation of initial mitigation, mean contact rates subsequently increased but did not return to pre-COVID levels. Increases in contacts post-relaxation were driven by working-age adults.ConclusionInformation on changes in contact patterns during physical distancing measures can guide more realistic representations of contact patterns in mathematical models for SARS-CoV-2 transmission.

scholarly journals Fine-scale family structure shapes influenza transmission risk in households: insights from a study of primary school students in Matsumoto city, 2014/15

2019 ◽  
Author(s):  
Akira Endo ◽  
Mitsuo Uchida ◽  
Adam J. Kucharski ◽  
Sebastian Funk
Keyword(s):  
Primary School ◽  
Family Structure ◽  
Seasonal Influenza ◽  
Household Composition ◽  
Transmission Risk ◽  
Secondary Effects ◽  
School Students ◽  
Household Transmission ◽  
Contact Patterns ◽  
Mother And Child

AbstractBackgroundHouseholds are important settings for the transmission of seasonal influenza. Previous studies found that the per-person risk of within-household transmission decreases with household size. However, more detailed heterogeneities driven by household composition and contact patterns have not been studied.MethodsWe employed a mathematical model which accounts for infections both from outside and within the household. The model was applied to citywide primary school surveillance data of seasonal influenza in 2014/15 season in Matsumoto city, Japan. We compared a range of models to estimate the structure of household transmission.ResultsFamilial relationship and household composition strongly influenced the transmission patterns of seasonal influenza in households. Children had substantially high risk of infection from outside the household (up to 20%) compared with adults (1-3%). Intense transmission was observed within-generation (between children/parents/grandparents) and also between mother and child, with transmission risks typically ranging around 5-20% depending on the pair and household composition.ConclusionsWe characterised heterogeneity in household transmission patterns of influenza. Children were identified as the largest source of secondary transmission, with family structure influencing infection risk. This suggests that vaccinating children would have stronger secondary effects on transmission than would be assumed without taking into account transmission patterns within the household.

scholarly journals Modelling the SARS-CoV-2 first epidemic wave in Greece: social contact patterns for impact assessment and an exit strategy from social distancing measures

2020 ◽  
Author(s):  
Vana Sypsa ◽  
Sotirios Roussos ◽  
Dimitrios Paraskevis ◽  
Theodore Lytras ◽  
S Sotirios Tsiodras ◽  
...  
Keyword(s):  
Impact Assessment ◽  
Attack Rate ◽  
Social Contact ◽  
Social Distancing ◽  
Relative Contribution ◽  
Contact Patterns ◽  
Social Mixing ◽  
Mixing Patterns ◽  
The Impact ◽  
Epidemic Wave

AbstractIn Greece, a nationwide lockdown to mitigate the transmission of SARS-CoV-2 was imposed on March 23, 2020. As by the end of April the first epidemic wave is waning, it is important to assess the infection attack rate and quantify the impact of physical distancing. We implemented a survey to assess social mixing patterns before the epidemic and during lockdown. We estimated R0 from surveillance data and assessed its decline as a result of physical distancing based on social contacts data. We applied a Susceptible-Exposed-Infectious-Recovered model to estimate the infection attack rate and the infection fatality ratio (IFR). As multiple social distancing measures were implemented simultaneously (schools/work/leisure), we assessed their overall impact as well as their relative contribution. R0 was estimated 2·38 (95%CI: 2·01,2·80). By April 26th, the infection attack rate was 0·12% (95%CrI: 0·06%,0·26%) and the IFR 1·12% (95%CrI: 0·55%,2·31%). During lockdown, daily contacts were reduced by 86·9% and the effective reproduction number reached 0·46 (95%CrI: 0·35,0·57). The reduction in R0 attributed to lockdown was 81·0% (95%CrI: 71·8%,86·0%) whereas the reduction attributed to each measure separately ranged between 10%-24%. We assessed scenarios with less disruptive social distancing measures as well as scenarios where measures are partially lifted after lockdown. This is the first impact assessment of the first wave of SARS-CoV-2 in a European country. It suggests that only multiple measures implemented simultaneously could reduce R0 below 1. Measuring social mixing patterns can be a tool for real-time monitoring of the epidemic potential.

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