Point Prevalence of SARS-CoV-2 Infection in Sweden at Six Time Points During 2020

Autor: Ramona Groenheit, Jessica Beser, Sharon Kühlmann Berenzon, Ilias Galanis, Edward van Straten, Jan Duracz, Marie Rapp, Disa Hansson, Mikael Mansjö, Sandra Söderholm, Shaman Muradrasoli, Anna Risberg, Richard Ölund, Andreas Wiklund, Kristoffer Metzkes, Matilda Lundberg, Philip Bacchus, Karin Tegmark Wisell, Andreas Bråve
Rok vydání: 2022
Předmět:
Zdroj: SSRN Electronic Journal.
ISSN: 1556-5068
DOI: 10.2139/ssrn.4031582
Popis: Background In order to estimate the prevalence and understand the spread of SARS-CoV-2 in Sweden, the Public Health Agency of Sweden, with support from the Swedish Armed Forces, conducted a series of point prevalence surveys between March and December 2020. Methods Sampling material and instructions on how to perform self-sampling of the upper respiratory tract were delivered to the homes of the participants. Samples were analysed by real-time PCR, and the participants completed questionnaires regarding symptoms. Findings The first survey in the Stockholm region in March 2020 included 707 participants and showed a SARS-CoV-2 prevalence of 2.5%. The following five surveys, performed on a national level, with between 2461 and 2983 participants, showed SARS-CoV-2 prevalences of 0.9% (April), 0.3% (May), 0.0% (August), 0.0% (September), and 0.7% (December). All positive cases who responded to questionnaires reported experiencing symptoms that occurred from 2 weeks before the date of sampling up to and including the date of sampling. Interpretation None of the individuals shown to be PCR-positive were asymptomatic at the time of sampling or in the 14 days prior to sampling. This is in contrast to many other surveys in which a substantial proportion of positive cases have been reported to be asymptomatic. Our surveys demonstrate a decreasing ratio between notified cases and the observed prevalence throughout the year, in line with increasing testing capacity and the consecutive inclusion of all symptomatic individuals in the case definition for testing.
Databáze: OpenAIRE