SCONE: Studying CONtacts of Elderly

Respiratory infections such as flu, corona and invasive pneumococcal disease cause the highest disease burden in the Netherlands, mainly among the elderly. Many vaccination programs are aimed at this group. However, the effect of these interventions can only be properly estimated with sufficient knowledge about transmission to and between the elderly. Objective By means of a diary study, we hope to gain a better insight into how contact patterns change with (advanced) age, gender, vulnerability and day of the week. Approach/method In this study, more than 700 people aged 70 and older kept a diary for a week. In it they mentioned who they had been in contact with: how old, what gender, how and where? About half did this in April 2021 when strict corona measures were still in place, and the other half in October 2021 when much more was possible again. Results The number of contacts outside the home of people aged 70 and older went from 17 per week in April 2021 to 24 per week in October 2021. This is an average, there are of course many differences between people. The results of this diary study provide a better (quantitative) insight into how contact patterns change with (advanced) age, gender, frailty and weekday, and into how effective intervention strategies aimed at the elderly can be. Because the two rounds took place in periods with many and few COVID-19 measures, it was possible to investigate what effect the measures had on the contacts of the elderly, and how these differed between vulnerable and non-vulnerable elderly people. We found that especially the oldest but still fit participants had very few contacts in April 2021. They mainly have contacts with peers, who are often vulnerable. As a result, they may have indirectly protected their vulnerable peers from exposure. Continued Ultimately, we can use these results in models to better understand how a disease like COVID-19 spreads in older Dutch people who still live at home. Recommendations from this study can be implemented in a subsequent contact study in the entire population. Including frailty in models can ultimately lead to policy advice that is more specifically aimed at vulnerable or non-frail elderly people living at home. However, this still requires more input from behavioral experts.