Details

Autor(en) / Beteiligte

• Bullard, Jared
• Dust, Kerry
• Funk, Duane
• Strong, James E
• Alexander, David
• Garnett, Lauren
• Boodman, Carl
• Bello, Alexander
• Hedley, Adam
• Schiffman, Zachary
• Doan, Kaylie
• Bastien, Nathalie
• Li, Yan
• Van Caeseele, Paul G
• Poliquin, Guillaume

Titel

Predicting Infectious Severe Acute Respiratory Syndrome Coronavirus 2 From Diagnostic Samples

Ist Teil von

• Clinical infectious diseases, 2020-12, Vol.71 (10), p.2663-2666

Ort / Verlag

US: Oxford University Press

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Oxford Journals 2020 Medicine

Beschreibungen/Notizen

• Abstract 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. Respiratory samples from COVID-19 patients with > 8 days of symptoms and a SARS-CoV-2 E gene reverse-transcription polymerase chain reaction cycle threshold value > 24 may predict lack of infectivity of those patients in a clinical and community context.