Social contact patterns and implications for infectious disease transmission – a systematic review and meta-analysis of contact surveys

Abstract

Background: Transmission of respiratory pathogens such as SARS-CoV-2 depends on patterns of contact and mixing across populations. Understanding this is crucial to predict pathogen spread and the effectiveness of control efforts. Most analyses of contact patterns to date have focussed on high-income settings. Methods: Here, we conduct a systematic review and individual-participant meta-analysis of surveys carried out in low- and middle-income countries and compare patterns of contact in these settings to surveys previously carried out in high-income countries. Using individual-level data from 28,503 participants and 413,069 contacts across 27 surveys we explored how contact characteristics (number, location, duration and whether physical) vary across income settings.Results: Contact rates declined with age in high- and upper-middle-income settings, but not in low-income settings, where adults aged 65+ made similar numbers of contacts as younger individuals and mixed with all age-groups. Across all settings, increasing household size was a key determinant of contact frequency and characteristics, with low-income settings characterised by the largest, most intergenerational households. A higher proportion of contacts were made at home in low-income settings, and work/school contacts were more frequent in high-income strata. We also observed contrasting effects of gender across income-strata on the frequency, duration and type of contacts individuals made. Conclusions: These differences in contact patterns between settings have material consequences for both spread of respiratory pathogens, as well as the effectiveness of different non-pharmaceutical interventions. Funding: This work is primarily being funded by joint Centre funding from the UK Medical Research Council and DFID (MR/R015600/1).

Predictors of SARS-CoV-2 Infection in University Students: A Case-Control Study

“…Indeed, university students who live away from their family often live with classmates or work colleagues. In this context, it is known that the household composition and the degree of intimacy has a considerable influence effect on the risk of contagion [ 50 , 51 ], and the number of close contacts may be lower in accommodation shared with associates, regardless of the number of roommates, compared to those that normally occur between family members. Furthermore, in our sample, only a small proportion of students resided in university accommodations, which have been suggested as places at high risk of outbreaks [ 15 ].…”

Novel estimates reveal subnational heterogeneities in disease-relevant contact patterns in the United States

“…While surveys or diary studies have now been used to produce national-level estimates of agespecific contact patterns in many countries around the world [6,[9][10][11][23][24][25], the majority of countries still lack nationally representative contact surveys. One stream of research has developed an approach for extrapolating synthetic national-level contact matrices in countries where no contact data are available at all [12,13].…”

“…First, the levels of interpersonal contact differ significantly across states. For example, in July 2020, members of the [18][19][20][21][22][23][24][25] age group in South Dakota had on average 11.6 total contacts in the past 24 hours, while members of the [18][19][20][21][22][23][24][25] age group in Washington had only 6.4 total contacts in the past 24 hours. Second, estimated statelevel contact patterns have high levels of assortative mixing by age for all states and across the course of the pandemic: at each month, the leading diagonal stripes visible in both state's estimated contact matrix in Fig 2 show highest relative rates of contact between members of the same age group at all or nearly all ages.…”

Substantial impact of mobility restrictions on reducing COVID-19 incidence in Italy in 2020

“…It was ranked second in the world in a recent review and meta-analysis of social contact patterns and related implications for communicable diseases. 8 For this reason, the feasibility of a tight lockdown was questioned. Furthermore, its efficacy was considered dubious by some scientists and public health authorities.…”