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. 2022 Apr:205:150-156.
doi: 10.1016/j.puhe.2022.02.004. Epub 2022 Feb 9.

The 1st year of the COVID-19 epidemic in Estonia: a population-based nationwide sequential/consecutive cross-sectional study

A Uusküla  1 , R Kalda  2 , M Solvak  3 , M Jürisson  2 , M Käärik  4 , K Fischer  4 , A Keis  2 , U Raudvere  5 , J Vilo  5 , H Peterson  5 , E Käärik  4 , M Metspalu  6 , T Jürgenson  7 , L Milani  6 , L Kolberg  5 , E-M Tiit  4 , K Vassil  8
Affiliations

The 1st year of the COVID-19 epidemic in Estonia: a population-based nationwide sequential/consecutive cross-sectional study

A Uusküla et al. Public Health. 2022 Apr.

Abstract

Objectives: The objective of this study was to assess the population prevalence of SARS-CoV-2 and changes in the prevalence in the adult general population in Estonia during the 1st year of COVID-19 epidemic.

Study design: This was a population-based nationwide sequential/consecutive cross-sectional study.

Methods: Using standardised methodology (population-based, random stratified sampling), 11 cross-sectional studies were conducted from April 2020 to February 2021. Data from nasopharyngeal testing and questionnaires were used to estimate the SARS-CoV-2 RNA prevalence and factors associated with test positivity.

Results: Between April 23, 2020, and February 2, 2021, results were available from 34,915 individuals and 27,870 samples from 11 consecutive studies. The percentage of people testing positive for SARS-CoV-2 decreased from 0.27% (95% confidence interval [CI] = 0.10%-0.59%) in April to 0.04% (95% CI = 0.00%-0.22%) by the end of May and remained very low (0.01%, 95% CI = 0.00%-0.17%) until the end of August, followed by an increase since November (0.37%, 95% CI = 0.18%-0.68%) that escalated to 2.69% (95% CI = 2.08%-2.69%) in January 2021. In addition to substantial change in time, an increasing number of household members (for one additional odds ratio [OR] = 1.15, 95% CI = 1.02-1.29), reporting current symptoms of COVID-19 (OR = 2.21, 95% CI = 1.59-3.09) and completing questionnaire in the Russian language (OR 1.85, 95% CI 1.15-2.99) were associated with increased odds for SARS-CoV-2 RNA positivity.

Conclusions: SARS-CoV-2 population prevalence needs to be carefully monitored as vaccine programmes are rolled out to inform containment decisions.

Keywords: COVID-19; Epidemiology; Estonia; Health inequalities; Prevalence; SARS-CoV-2; Surveillance.

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Figures

Fig. 1
Fig. 1
The COVID-19 epidemic in Estonia: daily numbers of new confirmed cases, the number of tests, proportion of positive tests and the number of deaths, 2020–2021.
Fig. 2
Fig. 2
Percentage of population testing positive for SARS-CoV-2 over time in Estonia during the 1st year of the COVID-19 epidemic 2020–2021. The grey area indicates 95% confidence intervals.
See this image and copyright information in PMC

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