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Epidemiological and Clinical Aspects of COVID-19; a Narrative Review

Goodarz Kolifarhood, Mohammad Aghaali, Hossein Mozafar Saadati, Niloufar Taherpour, Sajjad Rahimi, Neda Izadi, Seyed Saeed Hashemi Nazari



There are significant misconceptions and many obstacles in the way of illuminating the epidemiological and clinical aspects of COVID-19 as a new emerging epidemic. In addition, usefulness of some evidence published in the context of the recent epidemic for decision making in clinic as well as public health is questionable. However, misinterpreting or ignoring strong evidence in clinical practice and public health probably results in less effective and somehow more harmful decisions for individuals as well as subgroups in general populations of countries in the initial stages of this epidemic. Accordingly, our narrative review appraised epidemiological and clinical aspects of the disease including genetic diversity of coronavirus genus, mode of transmission, incubation period, infectivity, pathogenicity, virulence, immunogenicity, diagnosis, surveillance, clinical case management and also successful measures for preventing its spread in some communities.


COVID-19; severe acute respiratory syndrome coronavirus 2; epidemiology; public health; communicable diseases, emerging


Lu R, Zhao X, Li J, Niu P, Yang B, Wu H, et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet (London, England). 2020 Feb 22;395(10224):565-74. PubMed PMID: 32007145. Epub 2020/02/03. eng.

Zhang L, Shen FM, Chen F, Lin Z. Origin and evolution of the 2019 novel coronavirus. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2020 Feb 3. PubMed PMID: 32011673. Epub 2020/02/06. eng.

Perlman S. Another Decade, Another Coronavirus. New England Journal of Medicine. 2020;382(8):760-2.

Phelan AL, Katz R, Gostin LO. The Novel Coronavirus Originating in Wuhan, China: Challenges for Global Health Governance. Jama. 2020 Jan 30. PubMed PMID: 31999307. Epub 2020/01/31. eng.

Dong E, Du H, Gardner L. An interactive web-based dashboard to track COVID-19 in real time. The Lancet Infectious diseases. 2020 Feb 19. PubMed PMID: 32087114. Epub 2020/02/23. eng.

Kickbusch I, Leung G. Response to the emerging novel coronavirus outbreak. BMJ 2020;368:m406 doi: 10.1136/bmj.m406.

Kelly-Cirino C, Mazzola LT, Chua A, Oxenford CJ, Van Kerkhove MD. An updated roadmap for MERS-CoV research and product development: focus on diagnostics. BMJ global health. 2019 Jan 1;4(Suppl 2):e001105.

Chan JF, Yuan S, Kok KH, To KK, Chu H, Yang J, Xing F, Liu J, Yip CC, Poon RW, Tsoi HW. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. The Lancet. 2020 Feb 15;395(10223):514-23.

WHO Director-General's opening remarks at the media briefing on COVID-19 - 3 March 2020. Available at: https://www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---3-march-2020 Access Mar, 2020

Wong JEL, Leo YS, Tan CC. COVID-19 in Singapore-Current Experience: Critical Global Issues That Require Attention and Action. Jama. 2020 Feb 20. PubMed PMID: 32077901. Epub 2020/02/23. eng.

Gao QY, Chen YX, Fang JY. 2019 novel coronavirus infection and gastrointestinal tract. Journal of digestive diseases. 2020 Feb 25. PubMed PMID: 32096611. Epub 2020/02/26. eng.

Water, sanitation, hygiene and waste management for COVID-19.2020. Available at: https://www.who.int/publications-detail/water-sanitation-hygiene-and-waste-managementfor-covid-19 Access Mar,2020.

Bai Y, Yao L, Wei T, Tian F, Jin DY, Chen L, et al. Presumed Asymptomatic Carrier Transmission of COVID-19. Jama. 2020 Feb 21. PubMed PMID: 32083643. Pubmed Central PMCID: PMC7042844. Epub 2020/02/23. eng.

Coronavirus disease 2019 (COVID-19) Situation Report – 30.2020. Available at : https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200219-sitrep-30- covid-19.pdf?sfvrsn=3346b04f_2 Access Mar, 2020 .

Backer JA, Klinkenberg D, Wallinga J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20-28 January 2020. Euro Surveill. 2020;25(5):2000062. doi:10.2807/1560-7917.ES.2020.25.5.2000062.

Liu T, Hu J, Kang M, Lin L, Zhong H, Xiao J, et al. Transmission dynamics of 2019 novel coronavirus (2019-nCoV). bioRxiv. 2020;919787: (Preprint). Available from: 10.1101/2020.01.25.919787

Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia. New England Journal of Medicine. 2020;382(13):1199-207.

Swerdlow DL, Finelli L. Preparation for Possible Sustained Transmission of 2019 Novel Coronavirus: Lessons From Previous Epidemics. Jama. 2020;323(12):1129-30.

WHO. Statement on the meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV) 2020 [Available from: https://www.who.int/news-room/detail/23-01-2020-statement-on-themeeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-theoutbreak-of-novel-coronavirus-(2019-ncov).

Tang B, Wang X, Li Q, Bragazzi N, Tang S, Xiao Y, et al. Estimation of the Transmission Risk of the 2019-nCoV and Its Implication for Public Health Interventions. Journal of Clinical Medicine. 2020;9(2):462.

Liu Y, Gayle AA, Wilder-Smith A, Rocklov J. The reproductive number of COVID-19 is higher compared to SARS coronavirus. Journal of travel medicine. 2020 Mar 13;27(2). PubMed PMID: 32052846. Pubmed Central PMCID: PMC7074654. Epub 2020/02/14. eng.

Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) .2020 . Available at: https://www.who.int/docs/default-source/coronaviruse/who-china-jointmission-on-covid-19-final-report.pdf Access Mar, 2020.

Jung S-m, Akhmetzhanov AR, Hayashi K, Linton NM, Yang Y, Yuan B, et al. Real-Time Estimation of the Risk of Death from Novel Coronavirus (COVID-19) Infection: Inference Using Exported Cases. Journal of Clinical Medicine. 2020;9(2):523. PubMed PMID: doi:10.3390/jcm9020523.

Dorigatti I, Okell L, Cori A, Imai N, Baguelin M, Bhatia S, et al. Report 4: severity of 2019-novel coronavirus (nCoV). Imperial College London, London; 2020.

Wei M, Yuan J, Liu Y, Fu T, Yu X, Zhang Z-J. Novel Coronavirus Infection in Hospitalized Infants Under 1 Year of Age in China. Jama. 2020.

Lisa F P Ng, Julian A Hiscox. Coronaviruses in animals and humans. BMJ. 2020;368:m634. doi: 10.1136/bmj.m634

Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. [The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID19) in China]. Zhonghua Liu Xing Bing Xue Za Zhi. 2020;41(2):145-51.

Tian S, Hu N, Lou J, Chen K, Kang X, Xiang Z, et al. Characteristics of COVID-19 infection in Beijing. The Journal of infection. 2020 Apr;80(4):401-6. PubMed PMID: 32112886. Epub 2020/03/01. eng.

Mahase E. Coronavirus: covid-19 has killed more people than SARS and MERS combined, despite lower case fatality rate. BMJ. 2020;368:m641.

Novel CPERE. The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19) in China. Zhonghua liu xing bing xue za zhi= Zhonghua liuxingbingxue zazhi. 2020;41(2):145.

Ji Y, Ma Z, Peppelenbosch MP, Pan Q. Potential association between COVID-19 mortality and health-care resource availability. The Lancet Global health. 2020 Apr;8(4):e480. PubMed PMID: 32109372. Epub 2020/02/29. eng.

Ahmed SF, Quadeer AA, McKay MR. Preliminary identification of potential vaccine targets for the COVID-19 coronavirus (SARS-CoV-2) based on SARS-CoV immunological studies. Viruses. 2020;12(3):254.

Modjarrad K, Roberts CC, Mills KT, Castellano AR, Paolino K, Muthumani K, et al. Safety and immunogenicity of an anti-Middle East respiratory syndrome coronavirus DNA vaccine: a phase 1, open-label, single-arm, dose-escalation trial. The Lancet Infectious Diseases. 2019;19(9):1013-22.

Yong CY, Ong HK, Yeap SK, Ho KL, Tan WS. Recent Advances in the Vaccine Development Against Middle East Respiratory Syndrome-Coronavirus. Frontiers in microbiology. 2019;10:1781.

Lan L, Xu D, Ye G, Xia C, Wang S, Li Y, et al. Positive RT-PCR Test Results in Patients Recovered From COVID-19. Jama. 2020 Feb 27. PubMed PMID: 32105304. Pubmed Central PMCID: PMC7047852. Epub 2020/02/28. eng.

Ling Y, Xu SB, Lin YX, Tian D, Zhu ZQ, Dai FH, et al. Persistence and clearance of viral RNA in 2019 novel coronavirus disease rehabilitation patients. Chinese medical journal. 2020 Feb 28. PubMed PMID: 32118639. Epub 2020/03/03. eng.

Zhou L, Liu K, Liu HG. [Cause analysis and treatment strategies of "recurrence" with novel coronavirus pneumonia (covid-19) patients after discharge from hospital]. Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases. 2020;43(0):E028. doi: 10.3760/cma.j.cn112147-20200229-00219

Li Z, Yi Y, Luo X, Xiong N, Liu Y, Li S, et al. Development and Clinical Application of A Rapid IgM-IgG Combined Antibody Test for SARS-CoV-2 Infection Diagnosis. Journal of medical virology. 2020 Feb 27. PubMed PMID: 32104917. Epub 2020/02/28. eng.

TONE S. COVID-19 Hospital Adds Antibody Tests as Discharge Requirement 2020, March 5 [Available from: http://www.sixthtone.com/news/1005274/covid-19-hospital-addsantibody-tests-as-discharge-requirement.

WHO. Laboratory testing of 2019 novel coronavirus ( 2019-nCoV) in suspected human cases: interim guidance, Available at 2 March 2020. No. WHO/COVID19/laboratory/2020.4. World Health Organization, 2020.

Ai T, Yang Z, Hou H, Zhan C, Chen C, Lv W, et al. Correlation of Chest CT and RTPCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases. Radiology. 2020:200642.

Leeflang MM, Rutjes AW, Reitsma JB, Hooft L, Bossuyt PM. Variation of a test’s sensitivity and specificity with disease prevalence. Cmaj. 2013;185(11):E537-E44.

Lakes KD. Restricted sample variance reduces generalizability. Psychological assessment. 2013;25(2):643.

Chosewood LC, Wilson DE. Biosafety in microbiological and biomedical laboratories. US: Department of Health and Human Services, Public Health Service, Centers;2009. Available at: https://www.cdc.gov/labs/pdf/CDC-BiosafetyMicrobiologicalBiomedicalLaboratories-2009-P.PDF Access Mar, 2020.

Malaria surveillance, monitoring and evaluation: a reference manual. 2018. Available at:

https://www.who.int/malaria/publications/atoz/9789241565578/en/ Access Mar,2020.

Gostin LO, Hodge JG, Jr. US Emergency Legal Responses to Novel Coronavirus: Balancing Public Health and Civil Liberties. Jama. 2020 Mar 24;323(12):1131-2. PubMed PMID: 32207808. Epub 2020/03/25. eng.

World Health Organization. Novel Coronavirus (2019-nCoV); Situation Report 3; 2020. Available online: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/ situation-reports (accessed on 25 January 2020).

Gao J, Tian Z, Yang X. Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies. Bioscience trends. 2020 Mar 16;14(1):72-3. PubMed PMID: 32074550. Epub 2020/02/20. eng.

Wang M, Cao R, Zhang L, Yang X, Liu J, Xu M, et al. Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro. Cell research. 2020:1-3.

Beigel JH. Polyclonal and monoclonal antibodies for the treatment of influenza. Current opinion in infectious diseases. 2018;31(6):527-34.

Alansari K, Toaimah FH, Almatar DH, El Tatawy LA, Davidson BL, Qusad MIM. Monoclonal antibody treatment of RSV bronchiolitis in young infants: a randomized trial. Pediatrics. 2019;143(3):e20182308.

Cheng ZJ, Shan J. 2019 Novel coronavirus: where we are and what we know. Infection. 2020:1-9. 54.

WHO. Clinical management of severe acute respiratory infection when novel coronavirus (nCoV) infection is suspected: interim guidance. 307 https://www.who.int/docs/defaultsource/coronaviruse/clinical-management-of-novel-308 cov. pdf? sfvrsn= bc7da517_2. Published January. 2020;28.

Vetter P, Eckerle I, Kaiser L. Covid-19: a puzzle with many missing pieces. BMJ (Clinical research ed). 2020 Feb 19;368:m627. PubMed PMID: 32075791. Epub 2020/02/23. eng.

Shanmugaraj B, Malla A, Phoolcharoen W. Emergence of Novel Coronavirus 2019- nCoV: Need for Rapid Vaccine and Biologics Development. Pathogens. 2020;9(2):148.

Pang J, Wang MX, Ang IYH, Tan SHX, Lewis RF, Chen JI-P, et al. Potential Rapid Diagnostics, Vaccine and Therapeutics for 2019 Novel Coronavirus (2019-nCoV): A Systematic Review. Journal of Clinical Medicine. 2020;9(3):623.

Chen W-H, Strych U, Hotez PJ, Bottazzi ME. The SARS-CoV-2 Vaccine Pipeline: an Overview. Current Tropical Medicine Reports. 2020:1-4. 59. Gostin L. Public Health Emergency Preparedness: Globalizing Risk, Localizing Threats. Jama. 2018 Nov 6;320(17):1743-4.

Gostin L. Public Health Emergency Preparedness: Globalizing Risk, Localizing Threats. Jama. 2018 Nov 6;320(17):1743-4.

WHO. Coronavirus disease 2019 (COVID-19) Situation Report-46. Available at: https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200306-sitrep-46- covid-19.pdf?sfvrsn=96b04adf_2 Access Mar,2020.

Zeng Y, Zhen Y. Chinese medical staff request international medical assistance in fighting against COVID-19. The Lancet Global health. 2020 Feb 24. PubMed PMID: 32105614. Epub 2020/02/28. eng

DOI: https://doi.org/10.22037/aaem.v8i1.620

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