CRUSH COVID is an innovative multidisciplinary research project, in which researchers at five academic departments of Uppsala University are to collaborate with the Uppsala Region. The purpose of the project is to survey and attempt to control local outbreaks of COVID-19 in Uppsala County.

CRUSH COVID will assist the Uppsala Region’s Department of Communicable Disease Control and Prevention (Smittskyddsenheten) by delivering a knowledge base about the extent of infection in Uppsala County. The researchers will develop a method of combining information from various data sources and continuously reporting signs of local outbreaks. In addition, the study will help evaluate the Uppsala Region’s testing strategies and targeted measures. CRUSH COVID will also investigate which groups are at risk of being hit harder by COVID-19 than others.


Purpose and approach


The spread of COVID-19 during autumn and winter 2020 is likely to take the form of local (cluster) outbreaks. These will potentially cause both human suffering and a heavy burden on healthcare services, and make it more difficult for society to recover from the pandemic. Since a week or two often passes from when people become infected with SARS-CoV-2 to when they fall so ill as to need medical attention, it may currently be hard to detect local outbreaks at an early stage. The purpose of CRUSH COVID is to develop a method of detecting signals of increasing infection transmission at an early stage, so that the Uppsala Region can implement targeted measures.

COVID-19 is a novel disease, and there are therefore few scientific studies about which testing strategies are most effective and best slow down the spread of infection (“flatten the curve”) in the community. There are also large local variations among demographic groups in terms of the proportions who get themselves tested if they get possible symptoms. The Uppsala Region’s testing department has therefore taken the initiative for CRUSH COVID so that, alongside outstanding researchers at Uppsala University, it can scientifically evaluate testing strategies and various targeted measures in the Uppsala Region.


CRUSH COVID will develop a method of combining information from several data sources to pick up early signals of increased transmission of infection in real time.

These sources include:

  • The COVID Symptom Study (CSS) Sweden, a separate research study run by Uppsala University and Lund University in collaboration with King’s College London and ZOE Global Ltd. Everyone in Sweden who is 18 and over can volunteer for CSS Sweden and report daily, using the COVID Symptom Tracker, a mobile app, whether they have symptoms of the disease or not. Group-level results from CSS Sweden mean that we can find areas in the Uppsala Region where numerous people are reporting symptoms that match COVID-19.
  • The 1177 telephone helpline, which many residents in Sweden call if they have COVID-19 symptoms. We will be able to use group-level information from 1177 to find areas where many people have phoned to get medical advice about COVID-19.
  • Measurements of the SARS-CoV-2 virus in sewerage. Virus concentrations can be measured in wastewater, and the SARS-CoV-2 levels are an indication of where the spread of infection seems to be increasing or decreasing. The project will use results from SARS-CoV-2 measurements in wastewater from different parts of Uppsala County.
  • Group-level information from the Uppsala Infection Control Unit about the number of people testing positive, and seeking help at hospitals, from different postcode areas in Uppsala County.
  • Anonymous information from the CRUSH COVID questionnaires that respondents have filled in.

CRUSH COVID will continuously collect data on the proportion and number of people testing positive for the ongoing COVID-19 infection in the Uppsala Region, how many are admitted to hospital and the number of deaths due to COVID-19. The purpose is to be able to investigate and evaluate various testing strategies and targeted efforts.

Ethical approval

CRUSH COVID has received ethical approval from the Swedish Ethical Review Authority (ref. no. 2020-04210, 2020-06315 and 2020-06501). COVID Symptom Study (CSS) Sweden is a separate research study, also with ethical approval from the Authority (ref. nos. 2020-01803, 2020-04006, 2020-04145 and 2020-04451).

Mats Martinell

Senior Lecturer/Associate Professor at Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicin


Tove Fall

Professor at Department of Medical Sciences, Molecular epidemiology

Last modified: 2022-11-18