Assessment of SARS-CoV-2 infectivity of upper respiratory specimens from COVID-19 patients by virus isolation using VeroE6/TMPRSS2 cells. Issue 1 (24th February 2021)

• Record Type: Journal Article
• Authors: Yamada, Souichi; Fukushi, Shuetsu; Kinoshita, Hitomi; Ohnishi, Makoto; Suzuki, Tadaki; Fujimoto, Tsuguto; Saijo, Masayuki; Maeda, Ken
• Other Names: author non-byline.; Hanaoka Nozomu author non-byline.; Nojiri Naomi author non-byline.; Kawana-Tachikawa Ai author non-byline.; Kusagawa Shigeru author non-byline.; Ishikawa Koichi author non-byline.; Harada Shigeyoshi author non-byline.; Matsuoka Saori author non-byline.; Kikuchi Tadashi author non-byline.; Ishii Hiroshi author non-byline.; Seki Sayuri author non-byline.; Nakamura-Hoshi Midori author non-byline.; Miki Shoji author non-byline.; Runtuwene Lucky Ronald author non-byline.; Koizumi Nobuo author non-byline.; Iyoda Sunao author non-byline.; Takahashi Hideyuki author non-byline.; Izumiya Hidemasa author non-byline.; Mitobe Jiro author non-byline.; Yamamoto Shouji author non-byline.; Morita Masatomo author non-byline.; Lee Ken-ichi author non-byline.; Shimuta Ken author non-byline.; Saito Kyoko author non-byline.; Fukasawa Masayoshi author non-byline.; Hoshino Yasutaka author non-byline.; Miyazawa Ken author non-byline.; Nagi Minoru author non-byline.; Shimokawa Chikako author non-byline.; Morishima Yasuyuki author non-byline.; Sakudoh Takashi author non-byline.; Kaku Yoshihiro author non-byline.; Lim Chang Kweng author non-byline.; Tajima Shigeru author non-byline.; Maeki Takahiro author non-byline.; Nakayama Eri author non-byline.; Taniguchi Satoshi author non-byline.; Ogawa Motohiko author non-byline.; Kato Takanobu author non-byline.; Aly Hussein Hassan author non-byline.; Wakae Kousho author non-byline.; Fukano Kento author non-byline.;
• Is Part Of: BMJ open respiratory research. Volume 8:Issue 1(2021)
• Publication Date: 2021-02-24
• Subjects: COVID-19 -- viral infection; Respiratory organs -- Diseases -- Periodicals; Respiratory organs -- Diseases -- Treatment -- Periodicals; Respiratory therapy -- Periodicals; 616.2005
• DOI: 10.1136/bmjresp-2020-000830
• Languages: English
• ISSNs: 2052-4439

Abstract

Abstract : Background: An outbreak of novel coronavirus (SARS-CoV-2)-associated respiratory infectious diseases (COVID-19) emerged in 2019 and has spread rapidly in humans around the world. The demonstration of in vitro infectiousness of respiratory specimens is an informative surrogate for SARS-CoV-2 transmission from patients with COVID-19; accordingly, viral isolation assays in cell culture are an important aspect of laboratory diagnostics for COVID-19. Methods: We developed a simple and rapid protocol for isolating SARS-CoV-2 from respiratory specimens using VeroE6/TMPRSS2 cells, a cell line that is highly susceptible to the virus. We also investigated a correlation between isolation of SARS-CoV-2 and viral load detected by real-time RT-PCR (rRT-PCR) using N2 primer/probe set that has been developed for testing of COVID-19 in Japan. Results: The SARS-CoV-2 isolation protocol did not require blind passage of inoculated cells and yielded the results of viral isolation within 7 days after inoculation. Specimens with cycle threshold (Ct) values of <20.2, determined by rRT-PCR, were predicted to be isolation-positive. On the other hand, 6.9% of specimens with Ct values >35 were virus isolation-positive, indicating that low viral loads (high Ct values) in upper respiratory specimens do not always indicate no risk of containing transmissible virus. Conclusion: In combination with rRT-PCR, the SARS-CoV-2 isolation protocol provides a means for assessing the potential risk of transmissible virus in upper respiratory specimens.