TY - JOUR T1 - Importance of population-based longitudinal studies to understanding the impact of COVID-19 JF - Journal of Epidemiology and Community Health JO - J Epidemiol Community Health DO - 10.1136/jech-2021-217114 SP - jech-2021-217114 AU - Panayotes Demakakos Y1 - 2021/05/24 UR - http://jech.bmj.com/content/early/2021/05/23/jech-2021-217114.abstract N2 - High-quality population-based surveillance studies such as the COVID-19 Infection Survey and Real-time Assessment of Community Transmission Study primarily serve the purpose of generating timely and accurate estimates of the COVID-19 infection and transmission rates. However, describing the evolution of the COVID-19 pandemic is a different objective from understanding its multidimensional impact on people’s lives and describing the post-COVID-19 trajectories of the population. Surveillance studies can neither be used to study the COVID-19 period effect within life course and ageing perspectives nor be informative about a multitude of COVID-19 related impacts and implications beyond the short-term health impact.Against this backdrop, multidisciplinary population-based longitudinal studies can substantially add to our knowledge of the COVID-19 pandemic and its impact. In the UK, many population-based longitudinal studies have only recently incorporated serological tests and this impedes their ability to provide accurate estimates of COVID-19 status over the entire pandemic period. However, there are important dimensions of the COVID-19 pandemic that population-based longitudinal studies are well placed to study. Below I discuss some of these dimensions.The COVID-19 pandemic has short-term, medium-term and long-term implications. To fully understand them, one needs rich data that cover the COVID-19 period. They also need an appropriate pre-COVID-19 comparison basis, that is, data about how the population was doing before COVID-19. In the UK, several high-quality population-based longitudinal studies offer such data. For example, the English Longitudinal Study of Ageing (ELSA) has collected rich individual-level health, behavioural and social data from a representative sample aged ≥50 years over a period of 20 years, from 2002 to today. These data can be used to study the effect of … ER -