'Bern, get ready', BEready, a household-based cohort study for pandemic preparedness research in Switzerland: pilot study.

Objectives Research for pandemic response needs to be timely to inform evidence-based decision making. The lack of epidemiological data at the start of the COVID-19 pandemic led experts to call for cohorts that could rapidly supply data about newly emerging infectious diseases. The 'Bern, get ready' (BEready) study aims to establish a prospective 'pandemic preparedness cohort' in the canton of Bern, Switzerland. This cohort can be pivoted to the needs of a new pandemic pathogen. The aim of this pilot study was to investigate the potential response and to test the feasibility of procedures for BEready.Design Closed population-based cohort study.Setting Random sample of private households in the canton of Bern, Switzerland, that had previously responded to an online survey.Participants Adults, children and pets.Primary And Secondary Outcome Measures Enrolment as a percentage, associations between the agreement to participate and the demographic and socioeconomic variables of the invited household member, number of social contacts, proportion of samples collected, proportion of complete questionnaires and proportion of participants responding after 12 months.Intervention After the initial in-person visit with venous blood sampling, participants were followed up for 1 year. We tested remote data collection methods, with online questionnaires and self-collected capillary blood and nasopharyngeal samples, and established a biobank.Results The pilot study enrolled 106/1138 (9%) of invited households plus two additional households that had proactively contacted us. In total, we enrolled 193 people in 108 households (1.8 per household) and 44 pets between April and September 2023. We obtained and stored at least one venous and/or capillary baseline blood sample from 184/193 (95%) people and 40/44 (91%) pets. After 1 year, 172/193 (89%) people in 101/108 (94%) of households completed a follow-up survey, as did 22 owners of 34/44 (77%) pets. 151/172 (88%) respondents returned a follow-up capillary blood sample.Conclusions The response rate to the pilot study shows that obtaining high levels of participant enrolment in a pandemic preparedness cohort study is challenging. Data collection without face-to-face contact with a study team is feasible for household members and will be needed in BEready if control measures during a pandemic prevent in-person studies.