The Social Life of Infants in the Context of Infectious Disease Transmission; Social Contacts and Mixing Patterns of the Very Young

Abstract

Insight into how humans interact helps further understanding of the transmission of infectious diseases. For diseases such as pertussis, infants are at particular risk for severe outcomes. To understand the contact pattern of infants, especially those too young to be vaccinated, we sent contact diaries to a representative sample of 1000 mothers in the United Kingdom. We received 115 responses with a total of 758 recorded contacts. The average number of daily contacts for an infant was 6.68 overall and 5.7 for those aged ≤10 weeks. Of the latter, 2.1 (37%) contacts were with non-household members and were >15 minutes duration, suggesting that a cocooning programme may miss a substantial proportion of exposures leading to disease transmission. The least contact was between adolescents and infants. Thus the impact of adolescent (pertussis) vaccination on infants would likely be limited, unless it reduces transmission to other age groups whose contact with infants is greater.

Cost-effectiveness and programmatic benefits of maternal vaccination against pertussis in England

“…8 Other countries have used alternative strategies to control the transmission of pertussis such as a booster dose in adolescence. However the direct contact between adolescents and young infants is low, 21 hence the impact of this programme relies on the vaccine having an impact on disease transmission and the importance of adolescents in driving the infection among people who do have contact with infants. Pertussis incidence in infants under 1 year of age has continued to rise despite the introduction of the adolescent booster in the US, though coverage has not been high.…”

SOCRATES: An online tool leveraging a social contact data sharing initiative to assess mitigation strategies for COVID-19

“…For example, in studies from China [18] and the UK [21] groups of contacts instead of unique records were recorded and only infants were recruited, respectively. Note that other social contact surveys are available on Zenodo, though we have not yet included those surveys because they have a different set up.…”

Pertussis

“…Even an entire family vaccination may miss potential exposures as 37% of contacts of English infants aged ,10 weeks were non-household individuals lasting .15 minutes. 9…”