Zurich SARS-CoV-2 Cohort: Towards a long-term control of SARS-CoV-2 transmission – Identifying the epidemiological, immunological and viral genetic drivers of SARS-CoV-2 transmission and pathogenesis in a representative population-based cohort

The ongoing SARS-CoV-2 pandemic is an unprecedented global challenge with an enormous impact on public health, economies and societies worldwide. A wide variety in approaches have been taken to mitigate and control the spread of SARS-CoV-2 across countries and along different stages of the pandemic. After the successful response to the first pandemic wave, Switzerland is currently in a critical phase as the Federal Office of Public Health Health has eased the restrictions and re-opened its borders. In this phase, testing and tracing strategies and potential immunity conferred either by a previous infection or by a potential future vaccine are highly important for controlling and eventually ending the spread of SARS-CoV-2. However, key aspects regarding the main determinants of transmission, the characteristics of humoral and cellular immune responses and viral genetic factors and their relation to clinical disease courses remain unknown. An important reason for this uncertainty is the lack of large and representative patient populations for which the relevant phenotypes and genotypes of SARS-CoV-2 are simultaneously determined. A systematic and integrative population-level perspective, combined with a representative and country-specific population sample is thus crucial to address these issues in a way that will best inform public health strategies in Switzerland.

In collaboration with the Health Directorate of the Canton of Zurich, this project aims to address these knowledge gaps by establishing a representative population-based cohort of SARS-CoV-2 infected index cases and their close contacts in the Canton of Zurich. This will allow a detailed examination of SARS-CoV-2 transmission in the population by combining contact tracing with phylogenetic analyses, the characterization of immunological responses and clinical outcomes, as well as the establishment of a biobank with samples from infected individuals. Our results will be crucial to monitor and respond to the current pandemic and to guide public health strategies and policy in containing SARS-CoV-2 in Switzerland.

The project will be structured in five work packages (WP) with the following main objectives:

  • WP1: Determine long-term clinical outcomes among SARS-CoV-2 positive individuals.
  • WP2: Examine patterns of SARS-CoV-2 infection and transmission among infected index cases and their close contacts in the context of contact tracing.
  • WP3: Infer the transmission network by combining information from routine contact tracing and genetic sequences of SARS-CoV-2.
  • WP4: Characterize immune responses and the development of immunity among SARS-CoV-2 positive individuals by assessing both antibody and T-cell responses.
  • WP5: Determine and identify the impact of SARS-CoV-2 viral genetics on pathogenicity, transmissibility and immune responses.

The Zurich SARS-CoV-2 cohort study offers an integrative perspective by bringing together the expertise of epidemiologists, virologists, clinicians and computational biologists to investigate key aspects of SARS-CoV-2 infection, pathogenesis and transmission. Using an innovative approach by combining viral phylogenetics with complementary information from routine contact tracing, this project will provide insights about the early and current spread of the virus, and provide high-quality epidemiological data on viral transmission routes and factors influencing transmission. Furthermore, the Zurich SARS-CoV-2 cohort will provide a unique and representative setting for the detailed study of humoral and cellular immune responses and their correlation with clinical outcomes and viral genetic factors, which will allow conclusions about the development and duration of protection from SARS-CoV-2 infection. The close collaboration with the Health Directorate of the Canton of Zurich, as well as the active connection to and collaboration with the Corona Immunitas program, will allow timely feedback of information to public health decision-makers for the prevention of future waves of the pandemic, the protection of at-risk population groups and the development of national vaccination strategies for Switzerland.

For further information, please contact the study team via phone (+41 44 634 58 54) or e-mail zhcorona-cohort AT ebpi.uzh.ch.