The study on the prevalence of the coronavirus in Estonia
In a cross-sectional study consisting of eight survey waves, the researchers of the University of Tartu will ascertain the actual prevalence of the coronavirus and the progress of the epidemic in Estonia. A random statistical sample of 16,000 to 20,000 people will be studied across Estonia to give the state evidence-based data to form the strategy for the gradual exit from the emergency situation. The study is financed by the Government of the Republic.
The research team will present the government weekly interim conclusions that will form the basis for evaluating the efficacy of the emergency measures and amending them.
The prevalence of the coronavirus will be determined among both the symptomatic and the asymptomatic population. This way it will be possible to estimate the state-wide spread of the virus in different population groups and regions. The participation in the study is voluntary; people who have become part of the sample can refuse to be interviewed and/or tested at any moment in time.
The interviewing of the people who have been selected as part of the first wave sample will begin on April 23; the testing will begin on April 24. Each survey wave will last for one week.
„If we want to evaluate the efficacy of the measures enacted in the emergency situation and amend the decisions taken thus far in an evidence-based manner, it is important to know the data of the prevalence of the coronavirus among the population. Correct information enables us to select the correct methods."
The head of the monitoring survey,
Head of the Institute of Family Medicine and Public Health at the University of Tartu,
Professor of Family Medicine Ruth Kalda
More information on the survey can be reached from:
Ruth Kalda, Head of the Institute of Family Medicine and Public Health, University of Tartu, Professor of Family Medicine 58383863, ruth.kalda [ät] ut.ee
Mikk Jürisson, Research Fellow of Public Health, University of Tartu, 57813909, mikk.jurisson [ät] ut.ee
- Who will become part of the sample?
People will be selected into the random statistical sample of the cross-sectional study based on the population register data on their gender, age and location. Men and women 18 and over will be included in the study. The study will not include people who cannot or do not wish to participate in it. The people who have been invited to participate in the study have the option of ending their participation at any moment in time.
People from 17 regions of Estonia will be included in the sample of the study: from every county and separately from Tallinn and Tartu.
- How will the interviewing take place?
The panel survey is conducted by the social and market research company AS Emor who gets the information on the people in the sample from the population register.
The people who have been included in the sample will be sent an online questionnaire and those who agree to participate in the study will fill it out. The elderly are interviewed over the phone as well, and the interviewer fills out the electronic questionnaire during this. The interviewer calls the study subject, explains the goal of the study and asks whether the person who answered is willing to participate. If the answer is negative, the interview will not be carried out. If the answer is positive, a standardised interview is used.
Both those who answer by phone and those who answer online will be asked about the manifestation of symptoms and important background characteristics, e.g. comorbidities.
Those who have answered the questionnaire will then be contacted by Medicum to arrange the time and location of the testing site where the study participant should go for testing.
- How will the samples be gathered?
The existing public mobile testing stations, created at the initiative of SYNLAB and Medicum, will be used for testing (13 testing stations, of which 11 are on the mainland and 2 on the islands). The testing in them will be carried out by Medicum (Tallinn and Rakvere), Qvalitas (Tartu, Pärnu, Viljandi, Jõgeva, Haapsalu, Paide), Corrigo in Narva, the Ida-Viru Central Hospital in Kohtla-Järve, the Hiiumaa Hospital in Kärdla and the Kuressaare Hospital on Saaremaa. Testing at home will be carried out by Fertilitas (Tallinn and Harju County), Eldred Medical in Eastern Estonia, Alre in Southern Estonia and the hospital personnel with SYNLAB cars on Hiiumaa and Saaremaa.
The study participant must arrive for testing in a car, in order to ensure the highest level of safety. This is not due to a wish to prefer people who own a car, rather the goal is to avoid the virus spreading in public places and public transport. Taking a sample from a car guarantees the safety of both the medic and the testing subject. The samples will be taken through an open car window by a qualified healthcare worker. It is necessary to bring along an identification document to give a nasopharyngeal sample.
If people have special needs or cannot organize a car, the coronavirus test sample from the nasopharynx will be taken at home. A time will be arranged for this.
A PCR test from the nasopharynx will be used for testing; this shows the existence of the virus RNA in the organism and indicates to an active infection.
- What happens to the samples after this?
The analysis of the tests will take place at the Tallinn molecular diagnostics laboratory of SYNLAB, to which the tests will be transported twice a day. The results of the tests will be entered into the Patient Portal and the joint testing call centre of Medicum and SYNLAB will inform the test subjects of the test results.
All those that the study finds to be infected are monitored and interviewed weekly until the end of the disease. If the infected person does not become symptomatic, he or she will be interviewed within two weeks.
- How is the protection of personal data guaranteed?
The study subjects can be certain that their personal data will be gathered, kept and stored confidentially.
The survey company will get the personal data of the persons in the sample from the population register. The gathering and processing of the data is organized according to the Personal Data Protection Act. The personal and health data of the participants of the study will be gathered in the course of the monitoring programme, and AS Emor and SYNLAB Estonia will forward the data to the University of Tartu in an encrypted form. Only two previously determined members of the University of Tartu research team have the right to decrypt the personal data. The data that would enable to identify a person will be separated from the health data, encoded and kept separately.
The University of Tartu research team will not forward to third persons the data that would enable to identify the participants of the study. The results of the scientific study could be forwarded to other countries for international cooperation. In that case, the data that is sent to other countries will be anonymized, taking into account the rules for protecting personal data in the relevant country.
The Research Ethics Committee of the University of Tartu has approved the study.
- How many tests will be done and when?
In order to carry out the monitoring in three months, 16,000 to 20,000 tests will be conducted, i.e. 10,000 tests during the first months, 6000 tests during the second month and 4000 tests during the third month. Within each wave of the survey, 2000 to 4000 tests will be done in a week. Altogether, eight survey waves will take place within three months.
- What are the costs of the study?
The interviewing and testing of the people in the sample, the analysis of the data and the personnel costs of the research team are in the amount of €1.8 million altogether. The study is financed by the Government of the Republic.
- Why does the current approach to evaluating the prevalence of the epidemic need to be changed?
The Government of the Republic of Estonia has thus far based the healthcare policy decisions of the COVID-19 epidemic on the information on the most severe cases, the people in need of medical care and the infectiousness of symptomatic people, as well as the experience of other countries. In order to successfully contain the epidemic, it is necessary to get data on the actual prevalence of the disease. The monitoring will provide information on what the main background characteristics and risk factors (e.g. comorbidities, the size of the household, socioeconomic status, contact types etc.) of the SARS-CoV-2 infection are, and how these are connected to the prevalence of the disease. A long-term study helps to follow the change of the number and share of people infected over time, evaluate what factors contribute to this and what the impact of the emergency measures has been.
- What will we find out from the study?
- What the actual prevalence of the SARS-CoV-2 infection is among the population, in different population groups (according to age, gender, location and nationality) and among asymptomatic persons. What the number and share of infected persons is.
- What the dynamics of the SARS-CoV-2 prevalence is. How does the number and share of infected persons change over time and what are the factors connected to it.
- What are the main background characteristics and risk factors (comorbidities, size of the household, socioeconomic status, contact types etc.) connected to SARS-CoV-2. How these are connected to prevalence.
- What is the progress of the SARS-CoV-2 infection and the COVID-19 disease (recovery, symptoms, the severity of the disease, hospitalization, death) and how this is connected to the background characteristics and risk factors. Does the progress of the disease change over time.
- Who form the monitoring team?
The study is being prepared and conducted with an involvement of a broad-based collection of University of Tartu researchers, including experts from the University of Tartu Institute of Family Medicine and Public Health, Institute of Genomics, Institute of Computer Science, Institute of Mathematics and Statistics, Johan Skytte Institute of Political Studies.