Prevalence of coronavirus antibodies remains at the same level as in September, people's behaviour shows pandemic fatigue

A study led by the University of Tartu shows that the prevalence of coronavirus among adults has increased at a moderate rate. Over the past month, the prevalence of coronavirus antibodies has remained unchanged. However, the number of people who have been in close contact with the infected has increased, and there are more and more people who do not change their everyday behaviour after close contact.

During the study wave from 13 to 25 October, 2,455 people were tested, 30 of whom received a positive test result. Of these, ten had recovered from the disease and thus did not spread the virus any longer, while 20 were still infectious. On average, 1.2% of adults are currently infected with the coronavirus. About 0.9% of adults (on average every 111th adult) are estimated to be infectious.

The leader of the prevalence study, Professor of Family Medicine of the University of Tartu Ruth Kalda said the results indicate that the number of currently infectious adults is comparable to September. In the groups we studied, the increase in the prevalence of the virus has been moderate. The increase reflected in daily infection statistics is probably due to population groups not reflected in our study. For example, we know from the statistics of the Health Board that in recent weeks the infection rate of schoolchildren has increased exponentially," Kalda explained.

Antibody prevalence has remained almost unchanged since last month

In this wave, 2,312 people gave the blood sample for assessing the prevalence of coronavirus antibodies. 2,000 of them had antibodies against coronavirus. This shows that an estimated 76.4% of the adult population has antibodies. This percentage has remained almost unchanged compared to the previous study wave. There has been a slight increase in the percentage of people who have received antibodies by vaccination. “I am pleased to see that the prevalence of antibodies has reached 87% among people over 65," said Kalda.

As the overall antibody prevalence has remained almost unchanged since September, Kalda believes that a number of people who have had the disease without knowing that have also been vaccinated in the meantime. "The good news is that the prevalence of antibodies among vaccinated people is very high – 98%, regardless of the age group and the time of vaccination," said Kalda.

Close contact with an infected person does not make people change their behaviour

The most significant result of the behavioural analysis of this study wave is that about 75% of people who have been in close contact with a potentially infected person do not change their behaviour after that. This can be said about both vaccinated and unvaccinated people. At the same time, there has been a marked increase in the number of people who have been in contact with an infected person. While in September, almost every 20th adult could say that, it is every 11th by now. At present, people do not do much to reduce physical meetings or replace them with electronic means.

"These aspects of behaviour indicate that people are tired of the pandemic and do not pay much attention to precautions they need to take without formal orders, despite the worsening virus situation," said Kalda. However, the study team encourages everyone to assess their daily infection risks and pay greater attention to precautions to prevent illness. "Let’s get vaccinated, reduce direct contacts, wear a mask when we come into contact with others and stay at home with even minor signs of illness — these are small steps that have a significant effect in the larger picture," said Associate Professor of Public Health of the University of Tartu Mikk Jürisson, a member of the study team.

The study on the prevalence of coronavirus is carried out by a broad-based research group of the University of Tartu in cooperation with Synlab Eesti, Medicum and Kantar Emor.

For more information about the study, see the University of Tartu web page.

Further information: Ruth Kalda, Head of the Institute of Family Medicine and Public Health, Professor of Family Medicine, 5698 5599,