The University of Tartu has invited over 2,000 Estonian residents picked at random to participate in the latest phase of a coronavirus prevalence study.
The study will take on board recent localized outbreaks of COVID-19, such as that in Tartu itself, and is based on using nasal swabs as a testing method. At the same time, the university is continuing its serologically-based research, which has revealed that the virus may be considerably more widespread than previously thought.
Head of the monitoring survey and University of Tartu Professor of Family Medicine Ruth Kalda said that researchers have kept an eye on the daily infection statistics throughout summer, in order to come back to collecting data about the point prevalence of the virus across the country as the number of infections increases.
"Cases related to the outbreak in Tartu have reached other locations, so we need more detailed information on whether and to what extent the virus has spread to other Estonian regions," said Kalda.
Kalda added that while people were generally had behaved responsibly in spring, the summer inevitably brought along more active person-to-person communication as well as holidays abroad.
Kalda added that a return to the type of restrictions in place at the height of the pandemic in March to May was not something desired unless it proved absolutely necessary.
"Nobody wants the country‑wide restrictions to come back, so we must study whether the outbreak which started in Tartu is merely local, or has become more widespread."
At the time of writing the outbreak, traced to a nightclub in Tartu city which a COVID-19 carrier visited on July 18, has surpassed 30 cases, taking into account other recent confirmed cases reported from Tartu bars, restaurants and nightclubs in the past few days.
The study, which aims to cover 2,400 Estonian residents and represents the fifth wave of such research conducted by the university, will be carried out in conjunction with the government and its scientific council.
"We have been cooperating with the government to find evidence-based solutions for curbing the spread of the virus and coping with the crisis since the start of the COVID-19 outbreak," said University of Tartu Vice Rector for Research Kristjan Vassil, according to a university press release.
Ruth Kalda said the results of a recent study which focused on antibodies rather than taking samples from the nasal cavity proved why caution is needed.
This latest survey, called KoroSero-EST-1, found that only a fifth of those who have COVID-19 antibodies – in other words are coronavirus carriers – display symptoms.
This means that the virus is far more widespread than previously thought, up to 10 times more in the case of Tallinn.
"This confirms the existing belief that a virus transmitter might not even be aware of being infectious. This is why we cannot condemn all the infected but can do a lot ourselves to minimise the spread of the virus," said Kalda, who added it was wise to avoid crowded events and parties or, if this proved impossible, wear a surgical mask and follow hygiene principles.
Under no circumstances should an individual with even the mildest symptoms of potential COVID-19 attend a party, gathering or event, no matter who else is going, who they might hope to meet there and how long they may have been looking forward to the event.
The latest research sees private sector firm Emor sending email and SMS invites to those who might want to take part – participation is voluntary – from Thursday, August 6. The invites are sent on a random basis and make use of the population register.
Participants need to fill out a questionnaire and find an agreed time for their test, which involves a nasal swab. The findings will be shared with the government.
Koro-Sero-Est 2 is due for roll-out soon, in addition, and a genetic sequence study will also take place in a few weeks, as well as a monitoring system based on wastewater analysis.
Editor: Andrew Whyte