The C19PRC study is a large, longitudinal online survey of the general adult population aged 18 years and older during the COVID-19 pandemic. The study involved regular and timely repeated assessments as the pandemic unfolded. Although the core C19PRC Study team is based in the United Kingdom, existing collaborations were leveraged to establish similar studies in the Republic of Ireland, Spain, and Italy. VIDA COVID-19 follows the adult general population of Spain, and launched at two different assessment points: T1 at the peak of the pandemic (April 2020, in the midst of a nation-wide confinement) and T2 before the confinement measures began to unwind (May 2020, when daily deaths were declining in the country).