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 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 Quantifying social contact patterns in Minnesota during Stay-at-Home social distancing order

2021 ◽  
Author(s):  
Audrey M Dorelien ◽  
Narmada Venkateswaran ◽  
Jiuchen Deng ◽  
Kelly Searle ◽  
Eva Enns ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Social Contact ◽  
Negative Binomial Regression ◽  
Risk Groups ◽  
Social Distancing ◽  
Contact Patterns ◽  
Specific Contact ◽  
Contact Data ◽  
Age Structured ◽  
At Home

SARS-CoV-2 is primarily transmitted through person-to-person contacts. It is important to collect information on age-specific contact patterns because SARS-CoV-2 susceptibility, transmission, and morbidity vary by age. To reduce risk of infection, social distancing measures have been implemented. Social contact data, which identify who has contact with whom especially by age and place are needed to identify high-risk groups and serve to inform the design of non-pharmaceutical interventions. We estimated and used negative binomial regression to compare the number of daily contacts during the first wave (April-May 2020) of the Minnesota Social Contact Study, based on respondents age, gender, race/ethnicity, region, and other demographic characteristics. We used information on age and location of contacts to generate age-structured contact matrices. Finally, we compared the age-structured contact matrices during the stay-at-home order to pre-pandemic matrices. During the state-wide stay-home order, the mean daily number of contacts was 5.6. We found significant variation in contacts by age, gender, race, and region. Adults between 40 and 50 years had the highest number of contacts. Respondents in Black households had 2.1 more contacts than respondent in White households, while respondents in Asian or Pacific Islander households had approximately the same number of contacts as respondent in White households. Respondents in Hispanic households had approximately two fewer contacts compared to White households. Most contacts were with other individuals in the same age group. Compared to the pre-pandemic period, the biggest declines occurred in contacts between children, and contacts between those over 60 with those below 60.

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.

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.

Testing Saudi State Capacity: A Study to Investigate How the Government Responded to the covid-19 Pandemic

2021 ◽  
pp. 1-19
Author(s):  
Mamdouh A. Shouman ◽  
Abdulaziz S. Alkabaa
Keyword(s):  
Policy Implementation ◽  
Negative Binomial ◽  
State Capacity ◽  
Negative Binomial Regression ◽  
Arab Countries ◽  
Negative Binomial Regression Model ◽  
Independent Variables ◽  
Binomial Regression ◽  
Effective Policy ◽  
The Government

Abstract This study aimed at testing Saudi state capacity in its response to the covid-19 pandemic. The model investigated the significant impact of different curfew levels (a measure of state capacity) on covid-19 cases across five main cities. We used a Negative Binomial regression model to study the association between the covid-19 cases and other independent variables that include curfew levels. Our regression results have tested Saudi state capacity in four different curfew levels, revealing that the Saudi government exhibited its ability to implement one curfew level that decreased covid-19 cases. This curfew level (four) was the most effective policy implementation of all levels that assessed state capacity but required more resources and manpower. Hence, the Saudi state has the capacity to implement its desired policies, however, it needs an increased number of resources and manpower to do that. These findings render comparative implications to gcc monarchies and other Arab countries.

scholarly journals Measuring the effectiveness of COVID-19 containment policies in Italian regions: are we doing enough?

2021 ◽  
pp. 75-80
Author(s):  
Demetrio Panarello ◽  
Giorgio Tassinari
Keyword(s):  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Current Phase ◽  
Mobility Limitations ◽  
Italian Regions ◽  
Binomial Regression ◽  
Stringency Level ◽  
Restrictive Measures ◽  
Second Wave ◽  
Over Time

A successful fight against COVID-19 greatly depends on citizens’ adherence to the restrictive measures, which may not suffice alone. Making use of a containment index, data on sanctions, and Google’s movement trends across Italian regions, complemented by other sources, we investigate the extent to which compliance with the mobility limitations has affected the number of deaths over time in the period from the 24th of February 2020 to the 9th of November 2020, by using panel data for Italian regions, analysed through a negative binomial regression method. We also differentiated the study period, estimating two distinct models on two subsamples: until the 13th of September and since the 14th of September. In so doing, we show how the pandemic dynamics have changed between the first and the second wave of the emergency. Our results highlight that the importance of the restrictive measures and of citizens’ accord on their abidance has greatly increased since the end of the summer, also because the stringency level of the adopted measures has critically declined. Informing citizens about the effects and purposes of the restrictive measures is of paramount importance, especially in the current phase of the pandemic.

scholarly journals A Cross-Regional Analysis of the COVID-19 Spread during the 2020 Italian Vacation Period: Results from Three Computational Models Are Compared

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7319
Author(s):  
Luca Casini ◽  
Marco Roccetti
Keyword(s):  
Computational Models ◽  
Negative Binomial ◽  
Regional Analysis ◽  
Cognitive Model ◽  
Negative Binomial Regression ◽  
Virus Spread ◽  
Infected People ◽  
Italian Regions ◽  
Starting Point ◽  
Vacation Period

On 21 February 2020, a violent COVID-19 outbreak, which was initially concentrated in Lombardy before infecting some surrounding regions exploded in Italy. Shortly after, on 9 March, the Italian Government imposed severe restrictions on its citizens, including a ban on traveling to other parts of the country. No travel, no virus spread. Many regions, such as those in southern Italy, were spared. Then, in June 2020, under pressure for the economy to reopen, many lockdown measures were relaxed, including the ban on interregional travel. As a result, the virus traveled for hundreds of kilometers, from north to south, with the effect that areas without infections, receiving visitors from infected areas, became infected. This resulted in a sharp increase in the number of infected people; i.e., the daily count of new positive cases, when comparing measurements from the beginning of July to those from at the middle of September, rose significantly in almost all the Italian regions. Upon confirmation of the effect of Italian domestic tourism on the virus spread, three computational models of increasing complexity (linear, negative binomial regression, and cognitive) have been compared in this study, with the aim of identifying the one that better correlates the relationship between Italian tourist flows during the summer of 2020 and the resurgence of COVID-19 cases across the country. Results show that the cognitive model has more potential than the others, yet has relevant limitations. The models should be considered as a relevant starting point for the study of this phenomenon, even if there is still room to further develop them up to a point where they become able to capture all the various and complex spread patterns of this disease.

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.

Changing social contact patterns under tropical weather conditions relevant for the spread of infectious diseases

2014 ◽  
Vol 143 (2) ◽  
pp. 440-451 ◽  
Author(s):  
T.-C. CHAN ◽  
Y.-C. FU ◽  
J.-S. HWANG
Keyword(s):  
Infectious Diseases ◽  
Negative Binomial ◽  
Social Contact ◽  
Social Institutions ◽  
Weather Conditions ◽  
Weather Data ◽  
Tropical Regions ◽  
Model Free ◽  
Contact Patterns ◽  
The Tropics

SUMMARYWeather conditions and social contact patterns provide some clues to understanding year-round influenza epidemics in the tropics. Recent studies suggest that contact patterns may direct influenza transmission in the tropics as critically as the aerosol channel in temperate regions. To examine this argument, we analysed a representative nationwide survey dataset of contact diaries with comprehensive weather data in Taiwan. Methods we used included model-free estimated relative changes in reproduction number, R0; relative changes in the number of contacts; and model-based estimated relative changes in mean contacts using zero-inflated negative binomial regression models. Overall, social contact patterns clearly differ by demographics (such as age groups), personal idiosyncrasies (such as personality and happiness), and social institutions (such as the division of weekdays and weekend days). Further, weather conditions also turn out to be closely linked to contact patterns under various circumstances. Fleeting contacts, for example, tend to diminish when it rains hard on weekdays, while physical contacts also decrease during weekend days with heavy rain. Frequent social contacts on weekdays and under good weather conditions, including high temperature and low absolute humidity, all might facilitate the transmission of infectious diseases in tropical regions.

scholarly journals The Frequency and Context of Snacking among Children: An Objective Analysis Using Wearable Cameras

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 103
Author(s):  
Ryan Gage ◽  
Martin Girling-Butcher ◽  
Ester Joe ◽  
Moira Smith ◽  
Cliona Ni Mhurchu ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Environmental Changes ◽  
Eating Behaviour ◽  
Social Contact ◽  
Negative Binomial Regression ◽  
Binomial Regression ◽  
Wearable Cameras ◽  
Eating Occasions ◽  
Buying Behaviour ◽  
Main Meals

Snacking is a common eating behaviour, but there is little objective data about children’s snacking. We aimed to determine the frequency and context of children’s snacking (n = 158; mean age = 12.6 years) by ethnicity, gender, socioeconomic deprivation and body mass index (BMI) children. Participants wore wearable cameras that passively captured images of their surroundings every seven seconds. Images (n = 739,162) were coded for snacking episodes, defined as eating occasions in between main meals. Contextual factors analysed included: snacking location, food source, timing, social contact and screen use. Rates of total, discretionary (not recommended for consumption) and healthful (recommended for consumption) snacking were calculated using negative binomial regression. On average, children consumed 8.2 (95%CI 7.4, 9.1) snacks per day, of which 5.2 (95%CI 4.6, 5.9) were discretionary foods/beverages. Children consumed more discretionary snacks than healthful snacks in each setting and at all times, including 15.0× more discretionary snacks in public spaces and 2.4× more discretionary snacks in schools. Most snacks (68.9%) were sourced from home. Girls consumed more total, discretionary and healthful snacks than boys, and Māori and Pacific consumed fewer healthful snacks than New Zealand (NZ) Europeans. Results show that children snack frequently, and that most snacking involves discretionary food items. Our findings suggest targeting home buying behaviour and environmental changes to support healthy snacking choices.

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