scholarly journals The differential impact of physical distancing strategies on social contacts relevant for the spread of COVID-19: Evidence from a multi-country survey

2020 ◽  
Author(s):  
Emanuele Del Fava ◽  
Jorge Cimentada ◽  
Daniela Perrotta ◽  
André Grow ◽  
Francesco Rampazzo ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Age Groups ◽  
Social Contact ◽  
The United States ◽  
Social Contacts ◽  
Contact Patterns ◽  
The Uk ◽  
Facebook Advertising ◽  
Net Reproduction ◽  
The Impact

AbstractPhysical distancing measures are intended to mitigate the spread of COVID-19, even though their impact on social contacts and disease transmission remains unclear. Obtaining timely data on social contact patterns can help to assess the impact of such protective measures. We conducted an online opt-in survey based on targeted Facebook advertising campaigns across seven European countries (Belgium, France, Germany, Italy, Netherlands, Spain, United Kingdom (UK)) and the United States (US), achieving a sample of 53,708 questionnaires in the period March 13–April 13, 2020. Post-stratification weights were produced to correct for biases. Data on social contact numbers, as well as on protective behaviour and perceived level of threat were collected and used to the expected net reproduction number by week, Rt, with respect to pre-pandemic data. Compared to social contacts reported prior to COVID-19, in mid-April daily social contact numbers had decreased between 49% in Germany and 83% in Italy, ranging from below three contacts per day in France, Spain, and the UK up to four in Germany and the Netherlands. Such reductions were sufficient to bring Rt to one or even below in all countries, except Germany. Evidence from the US and the UK showed that the number of daily social contacts mainly decreased after governments issued the first physical distancing guidelines. Finally, although contact numbers decreased uniformly across age groups, older adults reported the lowest numbers of contacts, indicating higher levels of protection. We provided a comparable set of statistics on social contact patterns during the COVID-19 pandemic for eight high-income countries, disaggregated by week. As these estimates offer a more grounded alternative to the theoretical assumptions often used in epidemiological models, the scientific community could draw on this information for developing more realistic epidemic models of COVID-19.

scholarly journals Social contact patterns among employees in 3 U.S. companies during early phases of the COVID-19 pandemic, April to June 2020

2020 ◽  
Author(s):  
Moses C. Kiti ◽  
Obianuju G. Aguolu ◽  
Carol Y. Liu ◽  
Ana R. Mesa ◽  
Rachel Regina ◽  
...  
Keyword(s):  
Race And Ethnicity ◽  
Control Strategies ◽  
Age Groups ◽  
Social Contact ◽  
The United States ◽  
Median Number ◽  
Cross Sectional ◽  
Contact Patterns ◽  
The Uk ◽  
Spread Of Infection

2.AbstractImportanceDevising control strategies against diseases such as COVID-19 require understanding of contextual social mixing and contact patterns. There has been no standardized multi-site social contact study conducted in workplace settings in the United States that can be used to broadly inform pandemic preparedness policy in these settings.ObjectiveThe study aimed to characterize the patterns of social contacts and mixing across workplace environments, including on-site or when teleworking.DesignThis was a cross-sectional non-probability survey that used standardized social contact diaries to collect data. Employees were requested to record their physical and non-physical contacts in a diary over two consecutive days, documented at the end of each day. Employees from each company were enrolled through email and electronic diaries sent as individual links. Data were collected from April to June 2020.SettingTwo multinational consulting companies and one university administrative department, all located in Georgia, USA.ParticipantsEmployees opted into the study by accepting the invitation on a link sent via email.Main OutcomeThe outcome was median number of contacts per person per day. This was stratified by day of data collection, age, sex, race and ethnicity.ResultsOf 3,835 employees approached, 357 (9.3%) completed the first day of contact diary of which 304 completed both days of contact diary. There was a median of 2 contacts (IQR: 1-4, range: 0-21) per respondent on both day one and two. The majority (55%) of contacts involved conversation only, occurred at home (64%), and cumulatively lasted more than 4 hours (38%). Most contacts were repeated, and within same age groups, though participants aged 30-59 years reported substantial inter-generational mixing with children.ConclusionParticipating employees in 3 surveyed workplaces reported few contacts, similar to studies from the UK and China when shelter-in-place orders were in effect during the pandemic. Many contacts were repeated which may limit the spread of infection. Future rounds are planned to assess changes in contact patterns when employees resume work in the office after the lockdown due to COVID-19 pandemic.

scholarly journals Vaccinating Adolescents and Children Significantly Reduces COVID-19 Morbidity and Mortality across All Ages: A Popula-Tion-Based Modeling Study Using the UK as an Example

Vaccines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1180
Author(s):  
Tinevimbo Shiri ◽  
Marc Evans ◽  
Carla A. Talarico ◽  
Angharad R. Morgan ◽  
Maaz Mussad ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Age Groups ◽  
Population Level ◽  
Vital Role ◽  
Morbidity And Mortality ◽  
Transmission Model ◽  
Base Case ◽  
Global Public Health ◽  
The Uk ◽  
The Impact

Debate persists around the risk–benefit balance of vaccinating adolescents and children against COVID-19. Central to this debate is quantifying the contribution of adolescents and children to the transmission of SARS-CoV-2, and the potential impact of vaccinating these age groups. In this study, we present a novel SEIR mathematical disease transmission model that quantifies the impact of different vaccination strategies on population-level SARS-CoV-2 infections and clinical outcomes. The model employs both age- and time-dependent social mixing patterns to capture the impact of changes in restrictions. The model was used to assess the impact of vaccinating adolescents and children on the natural history of the COVID-19 pandemic across all age groups, using the UK as an example. The base case model demonstrates significant increases in COVID-19 disease burden in the UK following a relaxation of restrictions, if vaccines are limited to those ≥18 years and vulnerable adolescents (≥12 years). Including adolescents and children in the vaccination program could reduce overall COVID-related mortality by 57%, and reduce cases of long COVID by 75%. This study demonstrates that vaccinating adolescents and children has the potential to play a vital role in reducing SARS-CoV-2 infections, and subsequent COVID-19 morbidity and mortality, across all ages. Our results have major global public health implications and provide valuable information to inform a potential pandemic exit strategy.

scholarly journals Contact surveys reveal heterogeneities in age-group contributions to SARS-CoV-2 dynamics in the United States

2021 ◽  
Author(s):  
Taylor Chin ◽  
Dennis M. Feehan ◽  
Caroline O. Buckee ◽  
Ayesha S. Mahmud
Keyword(s):  
United States ◽  
Age Groups ◽  
The United States ◽  
Contact Rate ◽  
Age Group ◽  
Contact Rates ◽  
Contact Patterns ◽  
Age Structured ◽  
The Impact ◽  
Over Time

SARS-CoV-2 is spread primarily through person-to-person contacts. Quantifying population contact rates is important for understanding the impact of physical distancing policies and for modeling COVID-19, but contact patterns have changed substantially over time due to shifting policies and behaviors. There are surprisingly few empirical estimates of age-structured contact rates in the United States both before and throughout the COVID-19 pandemic that capture these changes. Here, we use data from six waves of the Berkeley Interpersonal Contact Survey (BICS), which collected detailed contact data between March 22, 2020 and February 15, 2021 across six metropolitan designated market areas (DMA) in the United States. Contact rates were low across all six DMAs at the start of the pandemic. We find steady increases in the mean and median number of contacts across these localities over time, as well as a greater proportion of respondents reporting a high number of contacts. We also find that young adults between ages 18 and 34 reported more contacts on average compared to other age groups. The 65 and older age group consistently reported low levels of contact throughout the study period. To understand the impact of these changing contact patterns, we simulate COVID-19 dynamics in each DMA using an age-structured mechanistic model. We compare results from models that use BICS contact rate estimates versus commonly used alternative contact rate sources. We find that simulations parameterized with BICS estimates give insight into time-varying changes in relative incidence by age group that are not captured in the absence of these frequently updated estimates. We also find that simulation results based on BICS estimates closely match observed data on the age distribution of cases, and changes in these distributions over time. Together these findings highlight the role of different age groups in driving and sustaining SARS-CoV-2 transmission in the U.S. We also show the utility of repeated contact surveys in revealing heterogeneities in the epidemiology of COVID-19 across localities in the United States.

scholarly journals Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3958 ◽  
Author(s):  
Thiripura Vino ◽  
Gurmeet R. Singh ◽  
Belinda Davison ◽  
Patricia T. Campbell ◽  
Michael J. Lydeamore ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Age Groups ◽  
Social Contact ◽  
Communicable Diseases ◽  
Household Structure ◽  
Indigenous Populations ◽  
Indigenous Australian ◽  
Different Populations ◽  
The Impact

Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non-Indigenous populations, but limited data are available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age, gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use these data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

scholarly journals Assessing Age-Specific Vaccination Strategies and Post-Vaccination Reopening Policies for COVID-19 Control Using SEIR Modeling Approach

2021 ◽  
Author(s):  
Xia Wang ◽  
Hulin Wu ◽  
Sanyi Tang
Keyword(s):  
Age Structure ◽  
Age Groups ◽  
Social Contact ◽  
The Elderly ◽  
Vaccination Rate ◽  
Social Contacts ◽  
Post Vaccination ◽  
Vaccination Strategies ◽  
Contact Patterns ◽  
Effect Of Age

AbstractBackgroundAs the availability of COVID-19 vaccines, it is badly needed to develop vaccination guidelines to prioritize the vaccination delivery in order to effectively stop COVID-19 epidemic and minimize the loss.MethodsWe evaluated the effect of age-specific vaccination strategies on the number of infections and deaths using an SEIR model, considering the age structure and social contact patterns for different age groups for each of different countries.ResultsIn general, the vaccination priority should be given to those younger people who are active in social contacts to minimize the number of infections; while the vaccination priority should be given to the elderly to minimize the number of deaths. But this principle may not always apply when the interaction of age structure and age-specific social contact patterns is complicated. Partially reopening schools, workplaces or households, the vaccination priority may need to be adjusted accordingly.ConclusionsPrematurely reopening social contacts could initiate a new outbreak or even a new pandemic out of control if the vaccination rate and the detection rate are not high enough. Our result suggests that it requires at least nine months of vaccination before fully reopening social contacts in order to avoid a new pandemic.

scholarly journals Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases

2017 ◽  
Author(s):  
Thiripura Vino ◽  
Gurmeet R Singh ◽  
Belinda Davison ◽  
Patricia T Campbell ◽  
Michael Lydeamore ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Age Groups ◽  
Social Contact ◽  
Communicable Diseases ◽  
Household Structure ◽  
Indigenous Populations ◽  
Indigenous Australian ◽  
Different Populations ◽  
The Impact

Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non Indigenous populations, but limited data is available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age,gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use this data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

scholarly journals Differential impact of physical distancing strategies on social contacts relevant for the spread of SARS-CoV-2: evidence from a cross-national online survey, March–April 2020

BMJ Open ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. e050651
Author(s):  
Emanuele Del Fava ◽  
Jorge Cimentada ◽  
Daniela Perrotta ◽  
André Grow ◽  
Francesco Rampazzo ◽  
...  
Keyword(s):  
Online Survey ◽  
Age Groups ◽  
Social Contact ◽  
Face Mask ◽  
Infection Transmission ◽  
Contact Patterns ◽  
The Face ◽  
Gradual Introduction ◽  
The Usa ◽  
Net Reproduction

ObjectivesWe investigate changes in social contact patterns following the gradual introduction of non-pharmaceutical interventions and their implications for infection transmission in the early phase of the pandemic.Design, setting and participantsWe conducted an online survey based on targeted Facebook advertising campaigns across eight countries (Belgium, France, Germany, Italy, the Netherlands, Spain, UK and USA), achieving a sample of 51 233 questionnaires in the period 13 March–12 April 2020. Poststratification weights based on census information were produced to correct for selection bias.Outcome measuresParticipants provided data on social contact numbers, adoption of protective behaviours and perceived level of threat. These data were combined to derive a weekly index of infection transmission, the net reproduction number Rt .ResultsEvidence from the USA and UK showed that the number of daily contacts mainly decreased after governments issued the first physical distancing guidelines. In mid-April, daily social contact numbers had decreased between 61% in Germany and 87% in Italy with respect to pre-COVID-19 levels, mostly due to a contraction in contacts outside the home. Such reductions, which were uniform across age groups, were compatible with an Rt equal or smaller than one in all countries, except Germany. This indicates lower levels of infection transmission, especially in a period of gradual increase in the adoption rate of the face mask outside the home.ConclusionsWe provided a comparable set of statistics on social contact patterns during the COVID-19 pandemic for eight high-income countries, disaggregated by week and other demographic factors, which could be leveraged by the scientific community for developing more realistic epidemic models of COVID-19.

scholarly journals Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases

2017 ◽  
Author(s):  
Thiripura Vino ◽  
Gurmeet R Singh ◽  
Belinda Davison ◽  
Patricia T Campbell ◽  
Michael Lydeamore ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Age Groups ◽  
Social Contact ◽  
Communicable Diseases ◽  
Household Structure ◽  
Indigenous Populations ◽  
Indigenous Australian ◽  
Different Populations ◽  
The Impact

Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non Indigenous populations, but limited data is available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age,gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use this data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

scholarly journals CoMix: Changes in social contacts as measured by the contact survey during the 1 COVID-19 pandemic in England between March 2020 and March 2021

2021 ◽  
Author(s):  
Amy Gimma ◽  
James D Munday ◽  
Kerry LM Wong ◽  
Pietro Coletti ◽  
Kevin van Zandvoort ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Virus Transmission ◽  
School Age Children ◽  
Data Set ◽  
Social Contacts ◽  
Contact Patterns ◽  
The Mean ◽  
The Government ◽  
The Uk ◽  
The Impact

Background: During the COVID-19 pandemic, the UK government imposed public health policies in England to reduce social contacts in hopes of curbing virus transmission. We measured contact patterns weekly from March 2020 to March 2021 to estimate the impact of these policies, covering three national lockdowns interspersed by periods of lower restrictions. Methods: Data were collected using online surveys of representative samples of the UK population by age and gender. We calculated the mean daily contacts reported using a (clustered) bootstrap and fitted a censored negative binomial model to estimate age-stratified contact matrices and estimate proportional changes to the basic reproduction number under controlled conditions using the change in contacts as a scaling factor. Results: The survey recorded 101,350 observations from 19,914 participants who reported 466,710 contacts over 53 weeks. Contact patterns changed over time and by participants' age, personal risk factors, and perception of risk. The mean of reported contacts among adults have reduced compared to previous surveys with adults aged 18 to 59 reporting a mean of 2.39 (95% CI 2.20 - 2.60) contacts to 4.93 (95% CI 4.65 - 5.19) contacts, and the mean contacts for school-age children was 3.07 (95% CI 2.89 - 3.27) to 15.11 (95% CI 13.87 - 16.41). The use of face coverings outside the home has remained high since the government mandated use in some settings in July 2020. Conclusions: The CoMix survey provides a unique longitudinal data set for a full year since the first lockdown for use in statistical analyses and mathematical modelling of COVID-19 and other diseases. Recorded contacts reduced dramatically compared to pre-pandemic levels, with changes correlated to government interventions throughout the pandemic. Despite easing of restrictions in the summer of 2020, mean reported contacts only returned to about half of that observed pre-pandemic.

scholarly journals Characteristics of human encounters and social mixing patterns relevant to infectious diseases spread by close contact: A survey in southwest Uganda

2017 ◽  
Author(s):  
O le Polain de Waroux ◽  
S Cohuet ◽  
D Ndazima ◽  
A J Kucharski ◽  
A Juan-Giner ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Control Strategies ◽  
Social Contact ◽  
The Elderly ◽  
Human Interactions ◽  
Contact Patterns ◽  
Social Mixing ◽  
Contact Survey ◽  
The Impact

ABSTRACTQuantification of human interactions relevant to infectious disease transmission through social contact is central to predict disease dynamics, yet data from low-resource settings remain scarce. We undertook a social contact survey in rural Uganda, whereby participants were asked to recall details about the frequency, type, and socio-demographic characteristics of any conversational encounter that lasted for ≥5 minutes (henceforth defined as ‘contacts’) during the previous day. An estimate of the number of ‘casual contacts’ (i.e. <5 minutes) was also obtained. A total of 568 individuals were included. On average participants reported having routine contact with 7.2 individuals (range 1-25). Children aged 5-14 years had the highest frequency of contacts and the elderly (≥65 years) the fewest (P<0.001). A strong age-assortative pattern was seen, particularly outside the household and increasingly so for contacts occurring further away from home. Adults aged 25-64 years tended to travel more and further than others, and males travelled more frequently than females. Our study provides detailed information on contact patterns and their spatial characteristics in an African setting. It therefore fills an important knowledge gap that will help more accurately predict transmission dynamics and the impact of control strategies in such areas.

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