The Population Attributable Fraction (PAF) of cases due to gatherings and groups with relevance to COVID-19 mitigation strategies

Ellen Brooks-Pollock; Jonathan M Read; Thomas House; Graham Medley; Matt J Keeling; Leon Danon

The Social Contact Survey (SCS) [9, 10] collected data on social contacts from 5,388 participants between 2009 and 2010 in the UK. Participants were asked to enumerate other people with whom they had had contact over the course of a single day. Contacts were defined as those with whom participants had a face-to-face conversation within 3 metres and/or physically touched skin-on-skin. Participants were able report individual contacts and up to five groups of contacts, for instance church groups, weddings, large work functions or multiple contacts at work. The 'groups' question was designed to aid participants in reporting multiple similar contacts. Group contacts were defined in the same way as individual contacts, i.e. if a person attended a concert with 1,000 people, but only spoke to 5 people, the number of recorded group contacts would be 5. Participants were asked whether members of the group knew each other.