Viral load as a marker of the risk of severe course and progression of COVID-19: a review


BACKGROUND. Clinical course of coronavirus disease (COVID-19) in patients infected by SARS-CoV-2 varies from the absolute absence of symptoms to the extremely severe viral pneumonias with the development of acute respiratory distress syndrome. In this context, investigation of the peculiarities of disease course in dependence of viral load (VL) is very interesting.

OBJECTIVE. The aim of this paper is to analyze the results of novel clinical studies, dedicated to VL estimation in different biological specimens and its correlation with the severity of COVID-19 clinical course.

RESULTS AND DISCUSSION. During the first months of 2020 there were published some scientific studies, which analyzed the association between VL and the severity of COVID-19 clinical course. It was established that VL was high at the beginning of the disease; in the sputum its value was higher than in throat and nasal swabs. In comparison to the mild course of COVID-19, severe course is characterized by higher VL and longer release of the virus into the environment. Apart from that, high VL is associated with the significant increase of proinflammatory cytokines’ levels, risk of disease progress and unfavorable prognosis.

CONCLUSIONS. VL can be considered a risk factor and the predictor of severe course of COVID-19. Measures, aimed at the effective decrease of VL on each stage of the disease, and the improvement of antiepidemic control must help to optimize the treatment and prevent the spread of infection.

Keywords: coronavirus disease, COVID-19, SARS-CoV-2, viral load, course severity, progress.


WHO Director-General’s opening remarks at the media briefing on COVID-19 – 11 March 2020. World Health Organization, 2020. Available at: https://www.who. int/dg/speeches/detail/who-director-general-sopening-remarks-at-the-media- briefing-on-covid-19-11-march-2020.

Wu Z., McGoogan J.M. Characteristics of and important lessons from the corona- virus disease 2019 (COVID-19) outbreak in China: summary of a report of 72 314 cases from the Chinese center for disease control and prevention. JAMA. 2020 Feb 24. doi: 10.1001/jama.2020.2648.

Mawaddah A., Gendeh H.S., Lum S.G., Marina M.B. Upper respiratory tract samp- ling in COVID-19. Malays J. Pathol. 2020 Apr; 42 (1): 23-35.

Peeri N.C., Shrestha N., Rahman M.S., Zaki R., Tan Z., Bibi S., Baghbanzadeh M., Aghamohammadi N., Zhang W., Haque U. The SARS, MERS and novel coronavi- rus (COVID-19) epidemics, the newest and biggest global health threats: what lessons have we learned? Int. J. Epidemiol. 2020.

Yu F., Du L., Ojcius D.M., Pan C., Jiang S. Measures for diagnosing and treating infections by a novel coronavirus responsible for a pneumonia outbreak origi- nating in Wuhan, China. Microbes Infect. 2020; 22: 74-79.

Patel A.B., Verma A. COVID-19 and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers: what is the evidence? JAMA. March 2020. doi: 10.1001/jama.2020.4812.

Mungroo M.R., Khan N.A., Siddiqui R. Novel coronavirus: current understanding of clinical features, diagnosis, pathogenesis, and treatment options. Pathogens. 2020 Apr 17; 9 (4). pii: E297. doi: 10.3390/pathogens9040297.

Iloeje U.H., Yang H.I., Su J., Jen C.L., You S.L., Chen C.J. Risk evaluation of viral load elevation and associated liver disease/cancer-in HBV (the REVEAL-HBV) study group. Predicting cirrhosis risk based on the level of circulating hepatitis B viral load. Gastroenterology. 2006 Mar; 130 (3): 678-86.

Chen C.J., Yang H.I., Su J., Jen C.L., You S.L., Lu S.N., Huang G.T., Iloeje U.H., REVEAL-HBV study group. Risk of hepatocellular carcinoma across a biological gradient of serum hepatitis B virus DNA level. JAMA. 2006 Jan 4; 295 (1): 65-73.

Ticehurst J.R., Hamzeh F.M., Thomas D.L. Factors affecting serum concentrations of hepatitis C virus (HCV) RNA in HCV genotype 1-infected patients with chronic hepatitis. J. Clin. Microbiol. 2007 Aug; 45 (8): 2426-33.

van der Meer A. J., Veldt B. J., Feld J. J., Wedemeyer H., Dufour J. F., Lammert F., Duarte-Rojo A., Heathcote E. J., Manns M. P., Kuske L., Zeuzem S., Hofmann W. P., de Knegt R. J., Hansen B. E., Janssen H. L. Association be- tween sustained virological response and all-cause mortality among patients with chronic hepatitis C and advanced hepatic fibrosis. JAMA. 2012 Dec 26; 308 (24): 2584-93.

Lalueza A., Folgueira D., Muñoz-Gallego I., Trujillo H., Laureiro J., Hernández- Jiménez P., Moral-Jiménez N., Castillo C., Ayuso B., Díaz-Pedroche C., Torres M., Arrieta E., Arévalo-Cañas C., Madrid O., Lumbreras C. Influence of viral load in the outcome of hospitalized patients with influenza virus infection. Eur. J. Clin. Microbiol. Infect. Dis. 2019 Apr; 38 (4): 667-673.

Lu P.X., Deng Y.Y., Yang G.L., Liu Y.X., Gan Y.G., Li G.B., Liu W.L., Liu Y., Zhang J., Ye R.X., Shan W.S., Zhou B.P. The relationship between chest CT findings and viral load in patients with novel influenza A (H1N1). Zhonghua Jie He He Hu Xi Za Zhi. 2010 Oct; 33 (10): 746-9.

Granados A., Peci A., McGeer A., Gubbay J. Influenza and rhinovirus viral load and disease severity in upper respiratory tract infections. J. Clin.Virol. 2017 Jan; 86: 14-19.

Zou L., Ruan F., Huang M., Liang L., Huang H., Hong Z., Yu J., Kang M., Song Y., Xia J., Guo Q., Song T., He J., Yen H., Peiris M., Wu J. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. N. Engl. J. Med. 2020 Mar 19; 382 (12): 1177-1179. doi: 10.1056/NEJMc2001737. Epub 2020 Feb 19.

Pan Y., Zhang D., Yang P., Poon L., Wang Q. Viral load of SARS-CoV-2 in clinical samples. Lancet Infect. Dis. 2020 Apr; 20 (4): 411-412. doi: 10.1016/S1473- 3099(20)30113-4. Epub 2020 Feb 24.

Yu F., Yan L., Wang N., Yang S., Wang L., Tang Y., Gao G., Wang S., Ma C., Xie R., Wang F., Tan C., Zhu L., Guo Y., Zhang F. Quantitative detection and viral load analysis of SARS-CoV-2 in infected patients. Clin. Infect. Dis. 2020 Mar 28. pii: ciaa345. doi: 10.1093/cid/ciaa345.

Zheng S., Fan J., Yu F., Feng B., Lou B., Zou Q., Xie G., Lin S., Wang R., Yang X., Chen W., Wang Q., Zhang D., Liu Y., Gong R., Ma Z., Lu S., Xiao Y., Gu Y., Zhang J., Yao H., Xu K., Lu X., Wei G., Zhou J., Fang Q., Cai H., Qiu Y., Sheng J., Chen Y., Liang T. Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, Jan-Mar 2020: retrospective cohort study. BMJ. 2020 Apr 21; 369: m1443. doi: 10.1136/bmj.m1443.

Liu Y., Liao W., Wan L., Xiang T., Zhang W. Correlation between relative nasopharyngeal virus RNA load and lymphocyte count disease severity in patients with COVID-19. Viral Immunol. 2020 Apr 10. doi: 10.1089/vim.2020.0062.

Yu X., Sun S., Shi Y., Wang H., Zhao R., Sheng J. SARS-CoV-2 viral load in sputum correlates with risk of COVID-19 progression. Crit. Care. 2020 Apr 23; 24 (1): 170. doi: 10.1186/s13054-020-02893-8.

Chen X., Zhao B., Qu Y., Chen Y., Xiong J., Feng Y., Men D., Huang Q., Liu Y., Yang B., Ding J., Li F. Detectable serum SARS-CoV-2 viral load (RNAaemia) is closely correlated with drastically elevated interleukin 6 (IL-6) level in critically ill COVID-19 patients. Clin. Infect. Dis. 2020 Apr 17. pii: ciaa449. doi: 10.1093/cid/ ciaa449.

How to Cite
Feshchenko, Y. I. (2020). Viral load as a marker of the risk of severe course and progression of COVID-19: a review. Infusion & Chemotherapy, (2), 5-10.

Author Biography

Y. I. Feshchenko, National Institute of Phthisiology and Pulmonology named after F. G. Yanovsky NAMS of Ukraine, Kyiv

Feschenko Yuri Ivanovych

Director of National Institute of Phthisiology and Pulmonology named after F.G. Yanovsky NAMS of Ukraine.
Academician of NAMS of Ukraine, MD, professor.
10, M. Amosova st., Kyiv, 03038, Ukraine.