Monitoring study conducted by the University of Tartu helps ascertain the prevalence of the coronavirus

On Tuesday, University of Tartu researchers will continue the monitoring study on the prevalence of the coronavirus to determine the extent of the spread of the virus among Estonian residents. Over the next two months, researchers plan to test in total up to 10,000 people nationwide in the course of the four stages of the study.

Recent data from the Health Board show that the virus is also spreading outside of the known outbreak sites and the source of infection remains unknown in a large number of new cases. Also, there is a large percentage of infected persons who have no evident symptoms of the disease. According to the head of the monitoring survey and UT Professor of Family Medicine Ruth Kalda, the situation has changed considerably compared to the time of the last wave of the study at the beginning of October.

“For better planning of virus control measures, an overview of the actual spread of the virus among the population is needed. The primary importance of our study is that it helps estimate the latent transmission of the virus. With a representative random sample, we can get a realistic picture of the amount of asymptomatic infected people who would not be referred to testing by family physicians,” said Kalda. “The larger the hidden prevalence, the larger is the expected surge in infections in the upcoming weeks. Unfortunately, however, those infected may also suffer severely from the disease and get hospitalised,” Kalda added.

Four waves of study with a larger sample than earlier

The monitoring study is conducted in four stages. During each stage, 2,400–2,500 people who are selected based on random sample will be tested.

People who are included in the sample are asked to respond to a questionnaire and thereafter to take a nasal swab test. This can be done in the public testing stations, the work of which is coordinated by Medicum. Disabled or elderly people and people with impaired mobility may order a testing team to test them at home. Synlab will transport the samples to its Tallinn laboratory for analysis. Participants in the study can view their test results in the Patient Portal at All infected people who are ascertained during the study will be regularly interviewed in order to follow the course of the disease.

Participation in the study is voluntary but, considering the complex epidemiological situation, scientists ask all people included in the sample to definitely participate. “It depends on the cooperativeness of all those invited to participate in the study whether we get an as precise picture as possible of the spread of the virus. This gives us necessary information to choose the appropriate measures for controlling the spread of the virus, and helps us better cope with the wave of the virus,” Kalda explained.

The University of Tartu researchers who are involved in the study include experts from the Institute of Family Medicine and Public Health, Institute of Genomics, Institute of Computer Science, Institute of Mathematics and Statistics, and Johan Skytte Institute of Political Studies.

The research company Kantar Emor will send out the questionnaires on Tuesday. Tests will be administered and analysed by Synlab and Medicum. The cost of the monitoring study is 880,000 euros, which will be covered from the reserves of the Ministry of Education and Research.

More information on the study is available on the University of Tartu website.

Further information: Ruth Kalda, Head of Institute of Family Medicine and Public Health, Professor of Family Medicine, University of Tartu, +372 5698 5599,

Sandra Sommer
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