BACKGROUND: Reverse-transcription polymerase chain reaction (RT-PCR) has become the primary method to diagnose viral diseases, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RT-PCR detects RNA, not infectious virus; thus, its ability to determine duration of infectivity of patients is limited. Infectivity is a critical determinant in informing public health guidelines/interventions. Our goal was to determine the relationship between E gene SARS-CoV-2 RT-PCR cycle threshold (Ct) values from respiratory samples, symptom onset to test (STT), and infectivity in cell culture. METHODS: In this retrospective cross-sectional study, we took SARS-CoV-2 RT-PCR-confirmed positive samples and determined their ability to infect Vero cell lines. RESULTS: Ninety RT-PCR SARS-CoV-2-positive samples were incubated on Vero cells. Twenty-six samples (28.9%) demonstrated viral growth. Median tissue culture infectious dose/mL was 1780 (interquartile range, 282-8511). There was no growth in samples with a Ct > 24 or STT > 8 days. Multivariate logistic regression using positive viral culture as a binary predictor variable, STT, and Ct demonstrated an odds ratio (OR) for positive viral culture of 0.64 (95% confidence interval [CI], .49-.84; P < .001) for every 1-unit increase in Ct. Area under the receiver operating characteristic curve for Ct vs positive culture was OR, 0.91 (95% CI, .85-.97; P < .001), with 97% specificity obtained at a Ct of > 24. CONCLUSIONS: SARS-CoV-2 Vero cell infectivity was only observed for RT-PCR Ct < 24 and STT < 8 days. Infectivity of patients with Ct > 24 and duration of symptoms > 8 days may be low. This information can inform public health policy and guide clinical, infection control, and occupational health decisions. Further studies of larger size are needed.
BACKGROUND: Reverse-transcription polymerase chain reaction (RT-PCR) has become the primary method to diagnose viral diseases, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RT-PCR detects RNA, not infectious virus; thus, its ability to determine duration of infectivity of patients is limited. Infectivity is a critical determinant in informing public health guidelines/interventions. Our goal was to determine the relationship between E gene SARS-CoV-2 RT-PCR cycle threshold (Ct) values from respiratory samples, symptom onset to test (STT), and infectivity in cell culture. METHODS: In this retrospective cross-sectional study, we took SARS-CoV-2 RT-PCR-confirmed positive samples and determined their ability to infect Vero cell lines. RESULTS: Ninety RT-PCR SARS-CoV-2-positive samples were incubated on Vero cells. Twenty-six samples (28.9%) demonstrated viral growth. Median tissue culture infectious dose/mL was 1780 (interquartile range, 282-8511). There was no growth in samples with a Ct > 24 or STT > 8 days. Multivariate logistic regression using positive viral culture as a binary predictor variable, STT, and Ct demonstrated an odds ratio (OR) for positive viral culture of 0.64 (95% confidence interval [CI], .49-.84; P < .001) for every 1-unit increase in Ct. Area under the receiver operating characteristic curve for Ct vs positive culture was OR, 0.91 (95% CI, .85-.97; P < .001), with 97% specificity obtained at a Ct of > 24. CONCLUSIONS:SARS-CoV-2 Vero cell infectivity was only observed for RT-PCR Ct < 24 and STT < 8 days. Infectivity of patients with Ct > 24 and duration of symptoms > 8 days may be low. This information can inform public health policy and guide clinical, infection control, and occupational health decisions. Further studies of larger size are needed.
Authors: Kevin Escandón; Angela L Rasmussen; Isaac I Bogoch; Eleanor J Murray; Karina Escandón; Saskia V Popescu; Jason Kindrachuk Journal: BMC Infect Dis Date: 2021-07-27 Impact factor: 3.090
Authors: Gunjan L Shah; Susan DeWolf; Yeon Joo Lee; Roni Tamari; Parastoo B Dahi; Jessica A Lavery; Josel Ruiz; Sean M Devlin; Christina Cho; Jonathan U Peled; Ioannis Politikos; Michael Scordo; N Esther Babady; Tania Jain; Santosha Vardhana; Anthony Daniyan; Craig S Sauter; Juliet N Barker; Sergio A Giralt; Cheryl Goss; Peter Maslak; Tobias M Hohl; Mini Kamboj; Lakshmi Ramanathan; Marcel Rm van den Brink; Esperanza Papadopoulos; Genovefa Papanicolaou; Miguel-Angel Perales Journal: J Clin Invest Date: 2020-12-01 Impact factor: 14.808
Authors: Hui Chen; Zhao Li; Sheng Feng; Melissa Richard-Greenblatt; Emily Hutson; Stefen Andrianus; Laurel J Glaser; Kyle G Rodino; Jianing Qian; Dinesh Jayaraman; Ronald G Collman; Abigail Glascock; Frederic D Bushman; Jae Seung Lee; Sara Cherry; Alejandra Fausto; Susan R Weiss; Hyun Koo; Patricia M Corby; Alfonso Oceguera; Una O'Doherty; Alfred L Garfall; Dan T Vogl; Edward A Stadtmauer; Ping Wang Journal: Clin Chem Date: 2021-12-30 Impact factor: 8.327
Authors: Qing Yang; Tassa K Saldi; Patrick K Gonzales; Erika Lasda; Carolyn J Decker; Kimngan L Tat; Morgan R Fink; Cole R Hager; Jack C Davis; Christopher D Ozeroff; Denise Muhlrad; Stephen K Clark; Will T Fattor; Nicholas R Meyerson; Camille L Paige; Alison R Gilchrist; Arturo Barbachano-Guerrero; Emma R Worden-Sapper; Sharon S Wu; Gloria R Brisson; Matthew B McQueen; Robin D Dowell; Leslie Leinwand; Roy Parker; Sara L Sawyer Journal: Proc Natl Acad Sci U S A Date: 2021-05-25 Impact factor: 11.205
Authors: Di Tian; Zhen Lin; Ellie M Kriner; Dalton J Esneault; Jonathan Tran; Julia C DeVoto; Naima Okami; Rachel M Greenberg; Sarah Yanofsky; Swarnamala Ratnayaka; Nicholas Tran; Maeghan Livaccari; Marla L Lampp; Noel Wang; Scott Tim; Patrick Norton; John Scott; Tony Y Hu; Robert Garry; Lee Hamm; Patrice Delafontaine; Xiao-Ming Yin Journal: J Mol Diagn Date: 2021-06-05 Impact factor: 5.568