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Had COVID-19 spread in the community before the first confirmed case in Nagasaki, Japan?
Norihito Kaku1, Kenji Ota1, Daisuke Sasaki2
1Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Japan; Department of Laboratory Medicine, Nagasaki University Hospital, 1-7-1 Sakamoto, Nagasaki, Japan.
Abstract:
This retrospective study evaluated stored nasopharyngeal swab samples from Japanese patients with influenza-like illness during the 2019/2020 season. We aimed to determine whether COVID-19 had spread in the community before the first confirmed case. The period of influenza season during 2019/2020 in Nagasaki was shorter than in previous influenza seasons. When the first COVID-19 case was reported in Nagasaki prefecture, the number of influenza cases were very low. No positive results for SARS-CoV-2 were detected in 182 samples that were obtained from adult outpatients. Our results revealed no large-scale spread of COVID-19 in the community before the first confirmed case.
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