Number Of Social Contacts Research Articles

Face recognition's practical relevance: Social bonds, not social butterflies

Research on individual differences in face recognition has provided important foundational insights: their broad range, cognitive specificity, strong heritability, and resilience to change. Elusive, however, has been the key issue of practical relevance: do these individual differences correlate with aspects of life that go beyond the recognition of faces, per se? Though often assumed, especially in social realms, such correlates remain largely theoretical, without empirical support. Here, we investigate an array of potential social correlates of face recognition. We establish social relationship quality as a reproducible correlate. This link generalises across face recognition tasks and across independent samples. In contrast, we detect no robust association with the sheer quantity of social connections, whether measured directly via number of social contacts or indirectly via extraversion-related personality indices. These findings document the existence of a key social correlate of face recognition and provide some of the first evidence to support its practical relevance. At the same time, they challenge the naive assumption that face recognition relates equally to all social outcomes. In contrast, they suggest a focused link of face recognition to the quality, not quantity, of one's social connections.

Social contacts in Switzerland during the COVID-19 pandemic: Insights from the CoMix study

To mitigate the spread of SARS-CoV-2, the Swiss government enacted restrictions on social contacts from 2020 to 2022. In addition, individuals changed their social contact behavior to limit the risk of COVID-19. In this study, we aimed to investigate the changes in social contact patterns of the Swiss population. As part of the CoMix study, we conducted a survey consisting of 24 survey waves from January 2021 to May 2022. We collected data on social contacts and constructed contact matrices for the age groups 0–4, 5–14, 15–29, 30–64, and 65 years and older. We estimated the change in contact numbers during the COVID-19 pandemic to a synthetic pre-pandemic contact matrix. We also investigated the association of the largest eigenvalue of the social contact and transmission matrices with the stringency of pandemic measures, the effective reproduction number (Re), and vaccination uptake. During the pandemic period, 7084 responders reported an average number of 4.5 contacts (95% confidence interval, CI: 4.5–4.6) per day overall, which varied by age and survey wave. Children aged 5–14 years had the highest number of contacts with 8.5 (95% CI: 8.1–8.9) contacts on average per day and participants that were 65 years and older reported the fewest (3.4, 95% CI: 3.2–3.5) per day. Compared with the pre-pandemic baseline, we found that the 15–29 and 30–64 year olds had the largest reduction in contacts. We did not find statistically significant associations between the largest eigenvalue of the social contact and transmission matrices and the stringency of measures, Re, or vaccination uptake. The number of social contacts in Switzerland fell during the COVID-19 pandemic and remained below pre-pandemic levels after contact restrictions were lifted. The collected social contact data will be critical in informing modeling studies on the transmission of respiratory infections in Switzerland and to guide pandemic preparedness efforts.

Social and psychological characteristics of personal alienation of older people during the war

In times of war, the elderly are a vulnerable category of the population that experiences not only material losses but also significant psychological and social challenges. Observing and studying the social and psychological characteristics of personal alienation of this group of people is an urgent task, as it can determine the quality of their lives and contribute to the development of effective support programmes. The article presents a study of the socio-psychological factors of personal alienation of the elderly. The authors analyse and consider the main approaches to understanding the concept of alienation. The article describes the author's model of the emergence of personal alienation in the elderly, which demonstrates the mechanism and process of the emergence and development of personal alienation in the elderly, and also considers the peculiarities of experiencing personal alienation by the elderly during the war. The model of personal alienation includes: a change in social status, an increase in the amount of unoccupied time, a decrease in the number of social contacts and a decrease in social activity, which in turn lead to the experience of non-compliance with social norms and standards, which causes a limitation of own resources and leads to personal alienation. The article also presents and discusses the author's structural model of personal alienation of the elderly. The proposed structural model identifies the socio-psychological and psychological factors that characterise the personal alienation of the elderly. The socio-psychological factors include: refusal to participate in the affairs of society, reduced social responsibility and social distancing. The psychological factors of personal alienation include: isolation, maladaptability, consistency in achieving goals, life goals, interest in life, conscious loneliness, emotional rejection of the present, negative assessment of the past, and anxiety. Personal alienation leads to a loss of subjectivity, which, due to the reduction of social contacts and social exclusion, further intensifies the experience of personal alienation by older people.

Life Satisfaction of Immigrants and Length of Stay in the New Country

A large amount of research is dedicated to the measurement of immigration trends and integration processes, but comparative studies of the components of immigrants’ well-being are rare. This paper investigates the link between the length of stay and the subjective well-being (SWB) of immigrants. A step-by-step regression method is used to understand interactions between different individual- and macro-level factors in the life satisfaction of immigrants. The results of the European Social Survey (ESS) show that the effect of length of stay on SWB is mitigated by numerous individual- and country-level variables. After all background variables are considered, newly arrived immigrants and those who have been in the new country for more than 20 years had a similar life satisfaction to that of the local-born population. Immigrants with 10 to 20 years’ experience in the country seem to have lower life satisfaction than the local-born population. The SWB of different immigrant groups is shaped by cultural background, economic coping, number of social contacts, perception of discrimination, and democracy. These factors influence the life satisfaction of migrants with different lengths of stay differently. The most vulnerable immigrant groups in Europe are those from Africa region.

Socio-demographic characteristics associated with COVID-19 vaccination uptake in Switzerland: longitudinal analysis of the CoMix study

BackgroundVaccination is an effective strategy to reduce morbidity and mortality from coronavirus disease 2019 (COVID-19). However, the uptake of COVID-19 vaccination has varied across and within countries. Switzerland has had lower levels of COVID-19 vaccination uptake in the general population than many other high-income countries. Understanding the socio-demographic factors associated with vaccination uptake can help to inform future vaccination strategies to increase uptake.MethodsWe conducted a longitudinal online survey in the Swiss population, consisting of six survey waves from June to September 2021. Participants provided information on socio-demographic characteristics, history of testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), social contacts, willingness to be vaccinated, and vaccination status. We used a multivariable Poisson regression model to estimate the adjusted rate ratio (aRR) and 95% confidence intervals (CI) of COVID-19 vaccine uptake.ResultsWe recorded 6,758 observations from 1,884 adults. For the regression analysis, we included 3,513 observations from 1,883 participants. By September 2021, 600 (75%) of 806 study participants had received at least one vaccine dose. Participants who were older, male, and students, had a higher educational level, household income, and number of social contacts, and lived in a household with a medically vulnerable person were more likely to have received at least one vaccine dose. Female participants, those who lived in rural areas and smaller households, and people who perceived COVID-19 measures as being too strict were less likely to be vaccinated. We found no significant association between previous SARS-CoV-2 infections and vaccination uptake.ConclusionsOur results suggest that socio-demographic factors as well as individual behaviours and attitudes played an important role in COVID-19 vaccination uptake in Switzerland. Therefore, appropriate communication with the public is needed to ensure that public health interventions are accepted and implemented by the population. Tailored COVID-19 vaccination strategies in Switzerland that aim to improve uptake should target specific subgroups such as women, people from rural areas or people with lower socio-demographic status.

Sustainable Next-Generation Network Design using Social Aware and Delay Tolerant Approach

With the ever-growing popularity of smartphones, new services are emerging where the local and positioning aspects become more important. Additionally, new routing algorithms are being developed based on various networking technology such as Delay Tolerance Networks (DTN), Deviceto- Device communication, Opportunistic Network, etc. DTN is categorized as stable and unstable, a continuous path between the source and the destination node. Here, communication is done by carrying the message through the intermediate relay node on the store and carry forward paradigm. In this work, a Sustainable Energy Delay Tolerance Approach (SEDA) considers nodes mobility patterns for energy-efficient data transmission. This routing model is based on the appropriate usage of node information along with node mobility and its contacts for data dissemination. Next step is applying some techniques to predict the most likely position for next encounter. We will design and implement a social relation-aware routing relation-awareness the social relation as a part of the routing matrix. We assume that most of the movement of nodes are included in various numbers of social contacts; therefore, there is a higher probability of message delivery to the destination. Simulation results show that the proposed routing protocol improves the delivery ratio by reducing network size and distance, which also impacts energy saving.

Sustainable nutritional behavior change (SNBC) model: How personal nutritional decisions bring about sustainable change in nutritional behavior

BackgroundThe aim of this qualitative study was to identify a practice level model that could explain a sustained change in nutritional behavior. MethodsThe study used three data inputs from four interviewees, one merged input from a married couple, as narrative interviews. The interviews were analyzed using grounded theory. ResultsCoexistence of a certain suffering and a triggering episode lead to the decision to change nutritional life-style by all interviewed. Maintenance of the self-determined newly learned nutritional behavior was supported by subject-related intrinsic motivation, the ability to reflect, and a low expectation of success from the behavioral change. Environment-related factors were identified as support from life-partner and peers. Subjects reported that the sustained nutritional behavior change impacted their holistic health through subject-perceived improved life quality, increase in the number of social contacts, and a change in personal attitudes and perception. The analysis remains limited, and at best hypothesis generating, in that only three data inputs from four interviewees were used. ConclusionIn this hypothesis-generating narrative interview study of four study subjects, volition, personal decision making, and long-term motivation (though not external determination) seemed to sustain a change in newly learned nutritional behavior.

Eviction from paradise: Lived experience, psycho-social and health effects of allotment garden loss

This mixed-methods paper examines the experience and effects of the loss of an allotment garden among gardeners in Zurich, Switzerland. The paper explores the subjective experience of garden loss using qualitative material gathered in field conversations with gardeners from an allotment area which was soon to be cleared for construction. In parallel, gardeners from the same area were surveyed before (2018) and after (2019) the clearance, thus constructing a natural experiment to measure effects on gardeners’ social networks, social support and general and mental health.The analysis of the qualitative material shows the (imminent) loss of the garden was a distressing experience for most participants, a result which is strongly supported by the descriptive analysis of several survey questions. Analysis of the quantitative data with ANCOVA models gives support to a negative effect of garden loss on the number of social contacts and on emotional well-being, but not on other factors.The experience of garden loss shows strong parallels to that of loss of a home, but also differs from it in relevant ways. Improved designs of similar natural experiments could lead to more reliable results. These would, however, require researchers to observe planning processes from a very early stage.

Образовательно-развивающая активность старшеклассников в условиях ограничений в связи с пандемией COVID-19

Most studies analyse educational process specifics during the spread of Covid-19 using higher education as an example. There is insufficient amount of research devoted to the study of students’ activity at different levels of school education. The purpose of the study is to identify the differences in terms of manifestation and determination of high school students’ educational and developmental activity in normal life and under social isolation. Hypothesis: educational and developmental activity of high school students increases under the conditions of forced isolation. This activity is expressed in an intensified interest in self-development. It is compensatory in nature due to a reduced number of social contacts and opportunities for the implementation of other forms of social activity. The study was carried out on a sample of high school students (N = 169) aged from 16 to 18 years. Techniques: the author's questionnaire aimed at identifying the degree of manifestation of educational and developmental activity; “Assessment of mental activation, interest, emotional tone, tension and comfort” (L. A. Kurganskiy, T. A. Nemchin); “Quality of Life Index” (R. S. Eliot, in the adaptation of N. E. Vodopyanova). The study found that educational and developmental activity of high school students under conditions of self-isolation is higher than in normal life. In general, their education and self-development activity is conditioned by their personal psycho-emotional states. If students are less active during distance learning, their activity is more determined by their mental states. If educational and developmental activity of high school students is high, they are focused on personal achievements, satisfied with their health, communication and support from others, and less prone to negative emotions. The results of the study can be used in psychological and pedagogical work with high school students, who are forced to be under conditions of social isolation in order to increase their educational and developmental activity.

Time trends in social contacts before and during the COVID-19 pandemic: the CONNECT study

BackgroundSince the beginning of the COVID-19 pandemic, many countries, including Canada, have adopted unprecedented physical distancing measures such as closure of schools and non-essential businesses, and restrictions on gatherings and household visits. We described time trends in social contacts for the pre-pandemic and pandemic periods in Quebec, Canada.MethodsCONNECT is a population-based study of social contacts conducted shortly before (2018/2019) and during the COVID-19 pandemic (April 2020 – February 2021), using the same methodology for both periods. We recruited participants by random digit dialing and collected data by self-administered web-based questionnaires. Questionnaires documented socio-demographic characteristics and social contacts for two assigned days. A contact was defined as a two-way conversation at a distance ≤ 2 m or as a physical contact, irrespective of masking. We used weighted generalized linear models with a Poisson distribution and robust variance (taking possible overdispersion into account) to compare the mean number of social contacts over time and by socio-demographic characteristics.ResultsA total of 1291 and 5516 Quebecers completed the study before and during the pandemic, respectively. Contacts significantly decreased from a mean of 8 contacts/day prior to the pandemic to 3 contacts/day during the spring 2020 lockdown. Contacts remained lower than the pre-COVID period thereafter (lowest = 3 contacts/day during the Christmas 2020/2021 holidays, highest = 5 in September 2020). Contacts at work, during leisure activities/in other locations, and at home with visitors showed the greatest decreases since the beginning of the pandemic. All sociodemographic subgroups showed significant decreases of contacts since the beginning of the pandemic. The mixing matrices illustrated the impact of public health measures (e.g. school closure, gathering restrictions) with fewer contacts between children/teenagers and fewer contacts outside of the three main diagonals of contacts between same-age partners/siblings and between children and their parents.ConclusionPhysical distancing measures in Quebec significantly decreased social contacts, which most likely mitigated the spread of COVID-19.

Time trends in social contacts of individuals according to comorbidity and vaccination status, before and during the COVID-19 pandemic

BackgroundAs we are confronted with more transmissible/severe variants with immune escape and the waning of vaccine efficacy, it is particularly relevant to understand how the social contacts of individuals at greater risk of COVID-19 complications evolved over time. We described time trends in social contacts of individuals according to comorbidity and vaccination status before and during the first three waves of the COVID-19 pandemic in Quebec, Canada.MethodsWe used data from CONNECT, a repeated cross-sectional population-based survey of social contacts conducted before (2018/2019) and during the pandemic (April 2020 to July 2021). We recruited non-institutionalized adults from Quebec, Canada, by random digit dialling. We used a self-administered web-based questionnaire to measure the number of social contacts of participants (two-way conversation at a distance ≤2 m or a physical contact, irrespective of masking). We compared the mean number of contacts/day according to the comorbidity status of participants (pre-existing medical conditions with symptoms/medication in the past 12 months) and 1-dose vaccination status during the third wave. All analyses were performed using weighted generalized linear models with a Poisson distribution and robust variance.ResultsA total of 1441 and 5185 participants with and without comorbidities, respectively, were included in the analyses. Contacts significantly decreased from a mean of 6.1 (95%CI 4.9–7.3) before the pandemic to 3.2 (95%CI 2.5–3.9) during the first wave among individuals with comorbidities and from 8.1 (95%CI 7.3–9.0) to 2.7 (95%CI 2.2–3.2) among individuals without comorbidities. Individuals with comorbidities maintained fewer contacts than those without comorbidities in the second wave, with a significant difference before the Christmas 2020/2021 holidays (2.9 (95%CI 2.5–3.2) vs 3.9 (95%CI 3.5–4.3); P<0.001). During the third wave, contacts were similar for individuals with (4.1, 95%CI 3.4–4.7) and without comorbidities (4.5, 95%CI 4.1–4.9; P=0.27). This could be partly explained by individuals with comorbidities vaccinated with their first dose who increased their contacts to the level of those without comorbidities.ConclusionsIt will be important to closely monitor COVID-19-related outcomes and social contacts by comorbidity and vaccination status to inform targeted or population-based interventions (e.g., booster doses of the vaccine).

The influence of risk perceptions on close contact frequency during the SARS-CoV-2 pandemic

Human behaviour is known to be crucial in the propagation of infectious diseases through respiratory or close-contact routes like the current SARS-CoV-2 virus. Intervention measures implemented to curb the spread of the virus mainly aim at limiting the number of close contacts, until vaccine roll-out is complete. Our main objective was to assess the relationships between SARS-CoV-2 perceptions and social contact behaviour in Belgium. Understanding these relationships is crucial to maximize interventions’ effectiveness, e.g. by tailoring public health communication campaigns. In this study, we surveyed a representative sample of adults in Belgium in two longitudinal surveys (survey 1 in April 2020 to August 2020, and survey 2 in November 2020 to April 2021). Generalized linear mixed effects models were used to analyse the two surveys. Participants with low and neutral perceptions on perceived severity made a significantly higher number of social contacts as compared to participants with high levels of perceived severity after controlling for other variables. Our results highlight the key role of perceived severity on social contact behaviour during a pandemic. Nevertheless, additional research is required to investigate the impact of public health communication on severity of COVID-19 in terms of changes in social contact behaviour.

Do Words Matter? Detecting Social Isolation and Loneliness in Older Adults Using Natural Language Processing.

Introduction: Social isolation and loneliness (SI/L) are growing problems with serious health implications for older adults, especially in light of the COVID-19 pandemic. We examined transcripts from semi-structured interviews with 97 older adults (mean age 83 years) to identify linguistic features of SI/L.Methods: Natural Language Processing (NLP) methods were used to identify relevant interview segments (responses to specific questions), extract the type and number of social contacts and linguistic features such as sentiment, parts-of-speech, and syntactic complexity. We examined: (1) associations of NLP-derived assessments of social relationships and linguistic features with validated self-report assessments of social support and loneliness; and (2) important linguistic features for detecting individuals with higher level of SI/L by using machine learning (ML) models.Results: NLP-derived assessments of social relationships were associated with self-reported assessments of social support and loneliness, though these associations were stronger in women than in men. Usage of first-person plural pronouns was negatively associated with loneliness in women and positively associated with emotional support in men. ML analysis using leave-one-out methodology showed good performance (F1 = 0.73, AUC = 0.75, specificity = 0.76, and sensitivity = 0.69) of the binary classification models in detecting individuals with higher level of SI/L. Comparable performance were also observed when classifying social and emotional support measures. Using ML models, we identified several linguistic features (including use of first-person plural pronouns, sentiment, sentence complexity, and sentence similarity) that most strongly predicted scores on scales for loneliness and social support.Discussion: Linguistic data can provide unique insights into SI/L among older adults beyond scale-based assessments, though there are consistent gender differences. Future research studies that incorporate diverse linguistic features as well as other behavioral data-streams may be better able to capture the complexity of social functioning in older adults and identification of target subpopulations for future interventions. Given the novelty, use of NLP should include prospective consideration of bias, fairness, accountability, and related ethical and social implications.

The spreading of SARS-CoV-2: Interage contacts and networks degree distribution.

Notable cross-country differences exist in the diffusion of the Covid-19 and in its lethality. Contact patterns in populations, and in particular intergenerational contacts, have been argued to be responsible for the most vulnerable, the elderly, getting infected more often and thus driving up mortality in some context, like in the southern European one. This paper asks a simple question: is it between whom contacts occur that matters or is it simply how many contacts people have? Due to the high number of confounding factors, it is extremely difficult to empirically assess the impact of single network features separately. This is why we rely on a simulation exercise in which we counterfactually manipulate single aspects of countries' age distribution and network structures. We disentangle the contributions of the kind and of the number of contacts while holding constant the age structure. More precisely, we isolate the respective effects of inter-age contact patterns, degree distribution and clustering on the virus propagation across age groups. We use survey data on face-to-face contacts for Great Britain, Italy, and Germany, to reconstruct networks that mirror empirical contact patterns in these three countries. It turns out that the number of social contacts (degree distribution) largely accounts for the higher infection rates of the elderly in the Italian context, while differences in inter-age contacts patterns are only responsible for minor differences. This suggests that policies specifically targeting inter-age contacts would be little effective.

Association between outdoor traffic air pollutants and spread of SARS-CoV-2 pandemic in Modena, Northern Italy

BACKGROUND AND AIM: Italy was the first European country severely affected by the SARS-CoV-2 pandemic, especially during the first wave in the North of the country. In particular, Modena is a city of Emilia-Romagna which is a region entirely included in the Po valley, one of European areas characterized by the heaviest air pollution levels due also to its orography. Previous studies yielded at a regional level suggested that higher air pollutant levels may increase both SARS-CoV-2 infection and mortality. METHODS: In this study, we further investigated the association between air pollutant exposure and spread of the SARS-CoV-2 using data collected from Modena municipality in the period February 2020-April 2021. We used traffic pollutant levels collected from an urban air quality monitoring station in the period January 2020-January 2021, including particulate matter (PM10), nitrogen oxides (NO2 and NOx), benzene, and black carbon (BC). We used a random-effects linear regression model within panel data analysis over the study period and we computed beta correlation coefficients (beta) with 95% confidence interval-CI between mean daily pollutant concentrations and SARS-CoV-2 daily positive cases diagnosed in Modena. RESULTS:We found a positive correlation between all traffic pollutants and SARS-CoV-2 cases, namely for PM10 beta was 1.23 (95%CI 1.00-1.46), lower for NOx (beta=0.66, 95%CI 0.56-0.75), and higher for NO2 (beta=1.95, 95%CI 1.59-2.31), benzene (beta=41.41, 95%CI 36.23-46.59), and BC (beta=5.95, 95%CI 1.19-10.72). CONCLUSIONS:Notwithstanding the limitations of use of aggregated data and potential the residual confounding, these findings seem to support the hypothesis that high levels of air pollution may favor the spread of SARS-CoV-2 infection, or alternatively that they reflect a higher mobility and number of social contacts that favor the spread of the infection. KEYWORDS: Air pollution, Traffic-related, Infectious diseases, Environmental epidemiology, Exposure assessment

The scaling of social interactions across animal species

Social animals self-organise to create groups to increase protection against predators and productivity. One-to-one interactions are the building blocks of these emergent social structures and may correspond to friendship, grooming, communication, among other social relations. These structures should be robust to failures and provide efficient communication to compensate the costs of forming and maintaining the social contacts but the specific purpose of each social interaction regulates the evolution of the respective social networks. We collate 611 animal social networks and show that the number of social contacts E scales with group size N as a super-linear power-law E=CN^beta for various species of animals, including humans, other mammals and non-mammals. We identify that the power-law exponent beta varies according to the social function of the interactions as beta = 1+a/4, with a approx {1,2,3,4}. By fitting a multi-layer model to our data, we observe that the cost to cross social groups also varies according to social function. Relatively low costs are observed for physical contact, grooming and group membership which lead to small groups with high and constant social clustering. Offline friendship has similar patterns while online friendship shows weak social structures. The intermediate case of spatial proximity (with beta =1.5 and clustering dependency on network size quantitatively similar to friendship) suggests that proximity interactions may be as relevant for the spread of infectious diseases as for social processes like friendship.

Modelling Voluntary General Population Vaccination Strategies during COVID-19 Outbreak: Influence of Disease Prevalence.

A novel statistical model based on a two-layer, contact and information, graph is suggested in order to study the influence of disease prevalence on voluntary general population vaccination during the COVID-19 outbreak. Details about the structure and number of susceptible, infectious, and recovered/vaccinated individuals from the contact layer are simultaneously transferred to the information layer. The ever-growing wealth of information that is becoming available about the COVID virus was modelled at each individual level by a simplified proxy predictor of the amount of disease spread. Each informed individual, a node in a heterogeneous graph, makes a decision about vaccination “motivated” by their benefit. The obtained results showed that disease information type, global or local, has a significant impact on an individual vaccination decision. A number of different scenarios were investigated. The scenarios showed that in the case of the stronger impact of globally broadcasted disease information, individuals tend to vaccinate in larger numbers at the same time when the infection has already spread within the population. If individuals make vaccination decisions based on locally available information, the vaccination rate is uniformly spread during infection outbreak duration. Prioritising elderly population vaccination leads to an increased number of infected cases and a higher reduction in mortality. The developed model accuracy allows the precise targeting of vaccination order depending on the individuals’ number of social contacts. Precisely targeted vaccination, combined with pre-existing immunity, and public health measures can limit the infection to isolated hotspots inside the population, as well as significantly delay and lower the infection peak.

Effect of social distancing on super-spreading diseases: why pandemics modelling is more challenging than molecular simulation

This paper aims to present some features of the non-Poissonian statistics of the spread of a disease like COVID19 to a community of chemical-physicists, who are more used to particle-based models. We highlight some of the reasons why creating a ‘transferable’ model for an epidemic is harder than creating a transferable model for molecular simulations. We describe a simple model to illustrate the large effect of decreasing the number of social contacts on the suppression of outbreaks of an infectious disease. Although we do not aim to model the COVID19 pandemic, we choose model parameter values that are not unrealistic for COVID19. We hope to provide some intuitive insight in the role of social distancing. As our calculations are almost analytical, they allow us to understand some of the key factors influencing the spread of a disease. We argue that social distancing is particularly powerful for diseases that have a fat tail in the number of infected persons per primary case. Our results illustrate that a ‘bad’ feature of the COVID19 pandemic, namely that super-spreading events are important for its spread, could make it particularly sensitive to truncating the number of social contacts.

Limits of lockdown: characterising essential contacts during strict physical distancing

Background: Coronavirus disease 2019 (COVID-19) has exposed health inequalities within countries and globally. The fundamental determining factor behind an individual’s risk of infection is the number of social contacts they make. In many countries, physical distancing measures have been implemented to control transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), reducing social contacts to a minimum. We characterise social contacts to understand the drivers and inequalities behind differential risks for aiding in planning SARS-CoV-2 mitigation programmes. Methods: We utilised an existing longitudinal birth cohort (n=6807) to explore social contact patterns and behaviours when strict physical distancing measures were in place during the UK’s first lockdown in March-May 2020. We used an online questionnaire to capture information on participant contact patterns, health, SARS-CoV-2 exposure, behaviours and impacts resulting from COVID-19. We quantified daily contacts and examined the association between covariates and numbers of daily total contacts using a negative binomial regression model. Results: A daily average of 3.7 [standard deviation = 10.6] total contacts outside the household were reported. Essential workers, specifically those in healthcare, had 4.5 times as many contacts as non-essential workers [incident rate ratio = 4.42 (95% CI: 3.88–5.04)], whilst essential workers in other sectors, mainly teaching and the police force had three times as many contacts [IRR = 2.84 (2.58–3.13)]. The number of individuals in a household, which largely reflects number of children, increases essential social contacts by 40%. Self-isolation effectively reduces numbers of contacts outside of the home, but not entirely. Conclusions: Contextualising contact patterns has highlighted the health inequalities exposed by COVID-19, as well as potential sources of infection risk and transmission. Together, these findings will aid the interpretation of epidemiological data and impact the design of effective control strategies for SARS-CoV-2, such as vaccination, testing and contact tracing.

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

BackgroundIn 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 generalized additive models for location, scale and shape (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 sex, 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 sex, 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.