Epidemiology and long-term clinical characteristics of COVID-19 in Amsterdam, the Netherlands Lessons learned and considerations for the future

Coronavirus disease 19 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in 2019 and caused a global pandemic. COVID-19 may present with a wide range of respiratory and non-specific symptoms, although asymptomatic infection may also occur. The first COVID-19 case in the Netherlands was notified on 27th February 2020 and the first wave of infections continued until 31st May 2020. The second wave emerged in autumn 2020 and continued until early 2021. It came to light during this time that some individuals experienced long-term, often debilitating symptoms after infection (“long COVID”). To date, long COVID pathogenesis remains unclear and no effective treatment exists. In this thesis, we first explored differences in COVID-19 burden in Amsterdam, the Netherlands, by migration background and city district (as a proxy for socio-economic status) during the first and second COVID-19 waves. We used routine surveillance data of notified COVID-19 infections, hospitalisations and deaths, matched to municipality data on country of birth and postal code of residence. We then described the evolution of COVID-19 symptoms, risk factors of delayed recovery, and the occurrence of severe fatigue and its determinants, up to 12 months after illness onset in a prospective cohort of adults with laboratory-confirmed SARS-CoV-2 infection (the VIS/RECoVERED study). Next, we zoomed in on two-year trajectories of COVID-19 symptoms in RECoVERED, the association between long COVID and aberrant inflammatory markers, and the effect of COVID-19 vaccination on existing long COVID symptoms. Together, these studies investigated the epidemiology and long-term clinical characteristics of COVID-19 in Amsterdam between 2020-2023.