Comparing The Viral Load of Severe Acute Respiratory Syndrome Coronavirus 2 in Different Human Specimens

Abstract = 607 times | PDF = 390 times

Main Article Content

Ali Hattem Hussain


This meta-analysis study analyzed the data of 47 recent studies with data related SARS-COV-2 viral load detection in different human specimens. 1099 patients were tested for SARS-COV-2 viral load using up to 19 different respiratory and non-respiratory specimens using RT-PCR by targeting different types of viral genes of which ORF1ab is the most commonly used target gene. 9909 specimens were taken from the patients. The mean of viral load cycle threshold value is 17.8 (±11.7), with a median of 15.95 with minimum value of 0.2 and a maximum value of 36.5. Nasopharyngeal swab has the highest positivity rate (90.5%) for viral load detection followed by Bronchoalveolar lavage, nasal swab, nasopharyngeal aspirate, throat swab and sputum. For the non-respiratory specimen, stool and rectal swab are most appropriate specimens followed by blood. The urine is not appropriate specimen for viral load detection due to very low sensitivity. The sputum was positive up to 23 days in a daily manner since start of symptoms except for the days 19, 21, and 23 that were negative for the virus. Three specimens, the nasopharyngeal swab, throat swab, and rectal swab, showed positive RT-PCR results before the appearance of COVID-19 clinical features.  Possible positive results can be present up to 43 days in throat swab, stool, and rectal swab. After negative conversion of respiratory specimens, the viral shedding can continue more than one month from stool and rectal swab. The 3rd day since onset of symptoms is the most day of testing (223/2935). The highest positivity of SARS-COV-2 viral load was recorded in day 16 since the onset of symptoms.              


SARS-COV-2, Viral load, specimen, nasopharyngeal swab, cycle threshold.


Download data is not yet available.

Article Details


[1] C. Lai, P. Shih, C. Ko, J. Tang, R. Hsueh, "Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges", International Journal of Antimicrobial Agents, Vol. 55, PP. 105924, 2020.
[2] H. Lu, W. Stratton, W. Tang, "Outbreak of pneumonia of unknown etiology in Wuhan China: the mystery and the miracle", Journal of Medical Virology, Vol. 92, no. 4, pp. 401-402, 2020.
[3] T. Singhal, "A Review of Coronavirus Disease-2019 (COVID-19)", Indian Journal of Pediatrics, Vol. 87, no. 4, pp. 281‐286, 2020.
[4] H. Li, M. Liu, H. Yu, L. Tang, K. Tang, "Coronavirus disease 2019 (COVID-19): current status and future perspectives", International journal of antimicrobial agents, Vol. 55, no. 5, pp. 105951, 2020.
[5] M. Linton, T. Kobayashi,Y. Yang, “Incubation Period and Other Epidemiological Characteristics of 2019 Novel Coronavirus Infections with Right Truncation: A Statistical Analysis of Publicly Available Case Data” Journal of clinical medicine, vol. 9, no. 2, pp. 538, 2020.
[6] Z. Wu, M. McGoogan, "Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention", Journal of the American Medical Association, Vol. 323, no. 13, pp. 1239–1242, 2020
[7] B. Udugama, P. Kadhiresan, N. Kozlowski, A. Malekjahani,, V. Osborne, H. Chen, B. Mubareka S, Gubbay, “Diagnosing COVID-19: The Disease and Tools for Detection”, ACS nano, Vol. 14, no. 4, pp. 3822-3835, 2020.
[8] W. Wang, Y Xu, R. Gao, R. Lu, K. Han, G. Wu, W. Tan, "Detection of SARS-CoV-2 in Different Types of Clinical Specimens", Journal of the American Medical Association, Vol. 323, no. 18, pp. 1843-1844, 2020.
[9] Y. Wu, C. Guo, L. Tang, Z. Hong, J. Zhou, X. Dong., L. Kuang, "Prolonged presence of SARS-CoV-2 viral RNA in faecal samples", The lancet Gastroenterology & hepatology, Vol. 5, no. 5, pp. 434-435, 2020.
[10] ‏ Y. Pan, D. Zhang, P. Yang, L. Poon, Q. Wang, "Viral load of SARS-CoV-2 in clinical samples", The Lancet Infectious Diseases, Vol. 20, no. 4, pp. 411-412, 2020.‏
[11] L. Zou, F. Ruan, M. Huang, L. Liang, H. Huang, Z. Hong, Q. Guo, "SARS-CoV-2 viral load in upper respiratory specimens of infected patients" New England Journal of Medicine, Vol. 382 no. 12, pp. 1177-1179, 2020.‏
[12] F. Xiao, M. Tang, X. Zheng, Y. Liu, X. Li, H. Shan, "Evidence for gastrointestinal infection of SARS-CoV-2. Gastroenterology, Vol. 158, no. 6, pp.1831-1833, 2020.
[13] T. Zhang, X. Cui, X. Zhao, J. Wang, J. Zheng, G. Zheng, Y. Xu, "Detectable SARS‐CoV‐2 viral RNA in feces of three children during recovery period of COVID‐19 pneumonia", Journal of Medical Virology, 2020.
[14] I. Lo, F. Lio, H. Cheong, I. Lei, H. Cheong, X. Zhong, N. Sin, " Evaluation of SARS-CoV-2 RNA shedding in clinical specimens and clinical characteristics of 10 patients with COVID-19 in Macau", International journal of biological sciences, Vol. 16, no. 10, pp. 1698, 2020.
[15] E. Young, X. Ong, S. Kalimuddin, G. Low, Y. Tan, J. Loh, K. Lau, "Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore", Journal of American Medical Association, Vol. 323, no. 15, pp. 1488-1494, 2020.
[16] ‏Y. Kim, H. Ko, Y. Kim, J. Kim, M. Kim, S. Chung, S. Chin, "Viral load kinetics of SARS-CoV-2 infection in first two patients in Korea", Journal of Korean medical science, Vol. 35, no. 7, 2019.‏
[17] C. Jones, B. Mühlemann, T. Veith, M. Zuchowski, J. Hofmann, A. Stein, C. Drosten, C, "An analysis of SARS-CoV-2 viral load by patient age", German Research network Zoonotic Infectious Diseases,‏ 2020.
[18] F. Chan, Y. Yip, W. To, C. Tang, Y. Wong, H. Leung, Y. Choi, "Improved molecular diagnosis of COVID-19 by the novel, highly sensitive and specific COVID-19-RdRp/Hel real-time reverse transcription-PCR assay validated in vitro and with clinical specimens", Journal of Clinical Microbiology, Vol. 58, no. 5, 2020.‏
[19] D. Yadav, A. Potdar, L. Choudhary, A. Nyayanit, M. Agrawal, M. Jadhav, S. Cherian, "Full-genome sequences of the first two SARS-CoV-2 viruses from India", Indian Journal of Medical Research, Vol. 151, no. 2, pp. 200, 2020.‏
[20] G. Seo, G. Lee, J. Kim, H. Baek, M. Choi, B. Ku, S. Lee, S. Jun, D. Park, G. Kim, J. Kim, O. Lee, T. Kim, C. Park, I. Kim," Rapid Detection of COVID-19 Causative Virus (SARS-CoV-2) in Human Nasopharyngeal Swab Specimens Using Field-Effect Transistor-Based Biosensor", ACS Nano, Vol. 14, no. 4, pp. 5135-5142, 2020.
[21] S. Kleiboeker, S. Cowden, J. Grantham, J. Nutt, A. Tyler, A. Berg, M. Altrich, "SARS-CoV-2 Viral load Assessment in Respiratory Samples", Journal of Clinical Virology, pp. 104439, 2020.‏
[22] Y. Chen, L. Chen, Q. Deng, G. Zhang, K. Wu, L. Ni, J. Yang," The presence of SARS‐CoV‐2 RNA in the feces of COVID‐19 patients", Journal of Medical Virology, 2020.‏
[23] F. Colavita, D. Lapa, F. Carletti, E. Lalle, L. Bordi, P. Marsella, G. Ippolito, " SARS-CoV-2 isolation from ocular secretions of a patient with COVID-19 in Italy with prolonged viral RNA detection", Annals of Internal Medicine, 2020.‏
[24] Y. Xu, X. Li, B. Zhu, H. Liang, C. Fang, G. Gong, H. Zhang, "Characteristics of pediatric SARS-CoV-2 infection and potential evidence for persistent fecal viral shedding", Nature medicine, vol. 26, no. 4, pp. 502-505, 2020.‏
[25] S. Zheng, J. Fan, F. Yu, B. Feng, B. Lou, Q. Zou, W. Chen, "Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020: retrospective cohort study", British Medical Journal, 369, 2020.‏
[26] L. Azzi, G. Carcano, F. Gianfagna, P. Grossi, D. Gasperina, A. Genoni, M. Fasano, F. Sessa, L. Tettamanti, F. Carinci, V. Maurino, A. Rossi, A. Tagliabue, A. Baj, "Saliva is a reliable tool to detect SARS-CoV-2", The Journal of infection, Vol. S0163-445, no. 20, pp. 30213-9, 2020.
[27] A. Emily, H. Jessica, H. Meei-L, P. Garrett, T. Scott, L. Pheobe, D. Sean, L. Diana, J. Keith, "Direct rt-qpcr detection of sars-cov-2 rna from patient nasopharyngeal swabs without an RNA extraction step", medRxiv and bioRxiv, 2020.
[28] J. Xia, J. Tong, M. Liu, Y. Shen, D. Guo, "Evaluation of coronavirus in tears and conjunctival secretions of patients with SARS-CoV-2 infection", Journal of medical virology, Vol. 92, no. 6, pp. 589-594, 2020.
[29] F. Zhou, T. Yu, R. Du, C. Bin, "Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study", Lancet, Vol. 395, no. 20, 2020.
[30] Y. Jun, E. Anderson, Z. Kang, F. Wang, P. Rao, E. Young, R. Agrawal, "Assessing viral shedding and infectivity of tears in coronavirus disease 2019 (COVID-19) patients", Ophthalmology, 2020.‏
[31] X. Jiang, M. Luo, Z. Zou, X. Wang, C. Chen, J. Qiu, "Asymptomatic SARS‐CoV‐2 infected case with viral detection positive in stool but negative in nasopharyngeal samples lasts for 42 days" Journal of Medical Virology, 2020.‏
[32] R. Yang, T. Deng, N. Wu, B. Yang, J. Li, B. Pan, "Persistent viral RNA positivity during recovery period of a patient with SARS‐CoV‐2 infection", Journal of medical virology, 2020.‏
[33] X. Chen, B. Zhao, Y. Qu, Y. Chen, J. Xiong, Y. Feng, J. Ding, "Detectable serum SARS-CoV-2 viral load (RNAaemia) is closely associated with drastically elevated interleukin 6 (IL-6) level in critically ill COVID-19 patients", MedRxiv, 2020.‏
[34] Y. Xing, W. Ni, Q. Wu, W. Li., G. Li, W. Wang, Q. Xing, "Dynamics of fecal SARS-CoV-2 in infected children during the convalescent phase", The Journal of Infection, 2020.
[35] ‏J. Zhang, X. Dong, Y. Cao, D. Yuan, B. Yang, Q. Yan, D. Gao, "Clinical characteristics of 140 patients infected with SARS‐CoV‐2 in Wuhan, China", Allergy, 2020.‏
[36] M. Kim, S. Chung, J. Jo, J. Lee, S. Kim, H. Woo, G. Han, "Identification of Coronavirus Isolated from a Patient in Korea with COVID-19", Osong public health and research perspectives, Vol. 11, no. 1, PP. 3, 2020.‏
[37] Q. Kam, F. Yung, L. Cui, R. Tzer, M. Mak, M. Maiwald, C. Thoon, "A well infant with coronavirus disease 2019 with high viral load", Clinical Infectious Diseases, 2020.‏
[38] T. Xu, C. Chen, Z. Zhu, M. Cui, C. Chen, H. Dai, Y. Xue, "Clinical features and dynamics of viral load in imported and non-imported patients with COVID-19", International Journal of Infectious Diseases, 2020.‏
[39] W. To, Y. Tsang, Y. Yip, H. Chan, C. Wu, C. Chan, C. Lung, "Consistent detection of 2019 novel coronavirus in saliva", Clinical Infectious Diseases, 2020.‏
[40] L. Wang, Y. Duan, W. Zhang, J. Liang, J. Xu, Y. Zhang, H. Li, "Epidemiologic and clinical characteristics of 26 cases of COVID-19 arising from patient-to-patient transmission in Liaocheng, China", Clinical Epidemiology, Vo. 12, pp. 387, 2020.‏
[41] Y. Xia, j. Wu, L. Liu, H. Xia, B. Jia, X. Huang, "Epidemiological and initial clinical characteristics of patients with family aggregation of COVID-19", Journal of Clinical Virology, pp. 104360, 2020.
[42] ‏ X. Lescure, L. Bouadma, D. Nguyen, M. Parisey, H. Wicky, S. Behillil, V. Enouf, "Clinical and virological data of the first cases of COVID-19 in Europe: a case series", The Lancet Infectious Diseases, 2020.‏
[43] X. He, H. Lau, P. Wu, X. Deng, J. Wang, X. Hao, X. Mo, "Temporal dynamics in viral shedding and transmissibility of COVID-19", Nature medicine, Vol. 26, no. 5, pp. 672-675, 2020.‏
[44] W. Zhao, L. He, X. Xie, J. Liu, "The Viral Load of 2019 Novel Coronavirus (COVID-19) has the potential to predict the clinical outcomes", Lancet, SSRN 3546047, 2020.
[45] F. Yu, L. Yan, N. Wang, S. Yang, L. Wang, Y. Tang, F. Wang, "Quantitative detection and viral load analysis of SARS-CoV-2 in infected patients", Clinical Infectious Diseases, 2020.‏
[46] R. Wölfel, M. Corman, W. Guggemos, M. Seilmaier, S. Zange, A. Müller, M. Hoelscher, "Virological assessment of hospitalized patients with COVID-2019", Nature, pp. 1-5, 2020.
[47] X. Marchand-Senécal, R. Kozak, S. Mubareka, N. Salt, B. Gubbay, A. Eshaghi, O. Ozaldin, "Diagnosis and Management of First Case of COVID-19 in Canada: Lessons applied from SARS", Clinical Infectious Diseases, 2020.
[48] J. Lim, S. Jeon, Y. Shin, J. Kim, M. Seong, J. Lee, J. Park, S. J, "Case of the index patient who caused tertiary transmission of COVID-19 infection in Korea: the application of lopinavir/ritonavir for the treatment of COVID-19 infected pneumonia monitored by quantitative RT-PCR", Journal of Korean medical science, Vol. 35, no. 6, 2020.‏
[49] Y. Lee, W. Li, P. Tsai, L. Chen, S. Syue, C. Li, .C. Ko, "A case of COVID-19 and pneumonia returning from Macau in Taiwan: Clinical course and anti-SARS-CoV-2 IgG dynamic", Journal of Microbiology, Immunology and Infection", 2020.‏
[50] A. Kujawski, K. Wong, P. Collins, L. Epstein, E. Killerby, M. Midgley, N. Anderson, "First 12 patients with coronavirus disease 2019 (COVID-19) in the United States", MedRxiv, 2020.‏
[51] L. Holshue, C. DeBolt, S. Lindquist, H. Lofy, J. Wiesman, H. Bruce, G. Diaz, "First case of 2019 novel coronavirus in the United States", New England Journal of Medicine, 2020.‏
[52] D. Chen, W. Xu, Z. Lei, Z. Huang, J. Liu, Z. Gao, L. Peng, "Recurrence of positive SARS-CoV-2 RNA in COVID-19: A case report", International Journal of Infectious Diseases, 2020.‏
[53] D. Wang, B. Hu, C. Hu, F. Zhu, X. Liu, J. Zhang, Y. Zhao, "Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus–infected pneumonia in Wuhan, China", Journal of the American Medical Association, Vol. 323, no. 11, pp. 1061-1069, 2020.‏
[54] J. Guan, Y. Ni, Y. Hu, H. Liang, Q. Ou, X. He, B. Du, "Clinical characteristics of coronavirus disease 2019 in China", New England journal of medicine, Vol. 382, no. 18, pp. 1708-1720, 2020.‏
[55] J. Meerhoff, L. Houben, J. Coenjaerts, L. Kimpen, W. Hofland, F. Schellevis, J. Bont, "Detection of multiple respiratory pathogens during primary respiratory infection: nasal swab versus nasopharyngeal aspirate using real-time polymerase chain reaction", European journal of clinical microbiology & infectious diseases, Vol. 29, no. 4, pp. 365-371, 2010.
[56] T. Magrone, M. Magrone, E. Jirillo, "Focus on Receptors for Coronaviruses with Special Reference to Angiotensin-converting Enzyme 2 as a Potential Drug Target-A Perspective", Endocrine, Metabolic & Immune Disorders Drug Targets, 2020.
[57] D. Vinayachandran, B. Saravanakarthikeyan, "Salivary diagnostics in COVID-19: Future research implications", Journal of Dental Sciences, 2020.
[58] I. Hamming, W. Timens, L. Bulthuis, T. Lely, G. Navis, H. van Goor, "Tissue distribution of ACE2 protein, the functional receptor for SARS coronavirus. A first step in understanding SARS pathogenesis", Journal of Pathology, Vol. 203, no. 2, pp. 631‐637, 2004.
[59] C. Jasper, y. Cyril, T. Kelvin, "Improved molecular diagnosis of COVID-19 by the novel, highly sensitive and specific COVID-19-RdRp/Hel real-time reverse transcription-PCR assay validated in vitro and with clinical specimens", Journal of Clinical Microbiology, Vol. 58, no. e00310-20, 2020.