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CC BY-NC-ND 4.0 · Journal of Digestive Endoscopy 2020; 11(01): 03-07
DOI: 10.1055/s-0040-1712187
Review Article

Epidemiology of COVID-19

Sudipta Dhar Chowdhury 
1   Department of Gastroenterology, Christian Medical College, Vellore, India
,
Anu Mary Oommen
2   Department of Community Medicine, Christian Medical College, Vellore, India
› Author Affiliations Funding None.
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Abstract

COVID-19, an infectious respiratory illness caused by the severe acute respiratory syndrome–corona virus 2 (SARS-CoV2), has now spread to multiple countries including India. The pace at which the disease spread in the last 4 months, since it was first recognized from China, is unprecedented. This review of the epidemiology of COVID-19 summarizes the burden of infection, transmission dynamics, and other related epidemiological features. While countries such as China, Italy, and the United States have particularly high-rates of infection, the disease is gradually spreading in India as well, threatening the health and economy of the country. Transmission in asymptomatic cases, early symptomatic phase, as well as limited access to testing in different settings are factors that have led to the rapid spread of infection. A large case series from China revealed that 81% of cases had mild symptoms, 14% had severe disease, and 5% were afflicted with critical illness. While the mortality in China was reported as 2.3%, Italy, with a high-proportion of elderly, reported a case fatality report of 7.2% due to higher infection and mortality rates among the elderly. Being a highly infectious disease, with a basic reproduction number between 2 to 3, COVID-19 is affecting a large number of healthcare workers, as evidenced by the fact that a sizeable portion of reported infections in the US included healthcare workers. Delivering health care for both COVID-19 affected individuals, as well those with other acute and chronic conditions, with limited access to healthcare facilities and services, are challenges for the health systems in low- and middle-income countries, which require immediate measures for health system strengthening across sectors.

Keywords

COVID-19 - coronavirus - epidemiology - pandemic - SARS-CoV2


Publication History

Article published online:
16 May 2020

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  • References

  • 1 Tyrrell DA, Bynoe ML. Cultivation of viruses from a high proportion of patients with colds. Lancet 1966; 1 (7428) 76-77
    PubMedGoogle Scholar
  • 2 Li Q, Guan X, Wu P. et al. Early transmission dynamics in Wuhan, China, of novel Coronavirus-infected pneumonia. N Engl J Med 2020; 382 (13) 1199-1207
    CrossrefPubMedGoogle Scholar
  • 3 Zhu N, Zhang D, Wang W. et al. China Novel Coronavirus Investigating and Research Team. A novel Coronavirus from patients with pneumonia in China, 2019. N Engl J Med 2020; 382 (08) 727-733
    CrossrefPubMedGoogle Scholar
  • 4 Lu R, Zhao X, Li J. et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet 2020; 395 (10224) 565-574
    CrossrefPubMedGoogle Scholar
  • 5 Coronaviridae Study Group of the International Committee on Taxonomy of VirusesNature Microbiology. The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. 2020;(e-pub ahead of print). doi https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7095448
  • 6 WHO. Naming the coronavirus disease (COVID-19) and the virus that causes it. Available at: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/naming-the-coronavirus-disease-(covid-2019)-and-the-virus-that-causes-it. Accessed April 16, 2020
  • 7 WHO statement on novel coronavirus in Thailand. Available at: https://www.who.int/news-room/detail/13-01-2020-who-statement-on-novel-coronavirus-in-thailand. Accessed April 16, 2020
  • 8 WHO. COVID-19 Dashboard. Available at: https://covid19.who.int/. Accessed April 17, 2020
  • 9 Ministry of Health and Family Welfare. Available at: Https://Www.Mohfw.Gov.In/ Accessed April 23, 2020
  • 10 Ralp R, Lew J, Zeng T. et al. 2019-nCoV (Wuhan virus), a novel Coronavirus: human-to-human transmission, travel-related cases, and vaccine readiness. J Infect Dev Ctries 2020; 14 (01) 3-17
    CrossrefPubMedGoogle Scholar
  • 11 Chan JF-W, Yuan S, Kok K-H. et al. A familial cluster of pneumonia associated with the 2019 novel Coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet 2020; 395 (10223) 514-523
    CrossrefPubMedGoogle Scholar
  • 12 Faridi S, Niazi S, Sadeghi K. et al. A field indoor air measurement of SARS-CoV-2 in the patient rooms of the largest hospital in Iran. Sci Total Environ 2020; 725: 138401
    CrossrefPubMedGoogle Scholar
  • 13 Wong SC-Y, Kwong RT-S, Wu TC. et al. Risk of nosocomial transmission of coronavirus disease 2019: an experience in a general ward setting in Hong Kong. J Hosp Infect 2020; (April): S0195-6701 (20) 30174-2
    Google Scholar
  • 14 Chen Y, Chen L, Deng Q, et al. The presence of SARS-CoV-2 RNA in feces of COVID-19 patients. J Med Virol 2020;(April) doi 10.1002/jmv.25825
  • 15 Liu J, Xiao Y, Shen Y, et al. Detection of SARS-CoV-2 by RT-PCR in anal from patients who have recovered from coronavirus disease 2019. J Med Virol 2020;(April) doi 10.1002/jmv.25875
  • 16 Park M, Cook AR, Lim JT, Sun Y, Dickens BL. A systematic review of COVID-19 epidemiology based on current evidence. J Clin Med 2020; 9 (04) E967
    CrossrefPubMedGoogle Scholar
  • 17 COVID-19 National Emergency Response Center, Epidemiology and Case Management Team, Korea Centers for Disease Control and Prevention. Coronavirus disease-19: summary of 2,370 contact investigations of the first 30 cases in the Republic of Korea. Osong Public Health Res Perspect 2020; 11 (02) 81-84
    CrossrefPubMedGoogle Scholar
  • 18 Burke RM, Midgley CM, Dratc A. et al. Active monitoring of persons exposed to patients with confirmed COVID-19 - United States, January-February 2020. MM. WR Morb Mortal Wkly Rep 2020; 69 (09) 245-246
    Google Scholar
  • 19 Lauer SA, Grantz KH, Bi Q, et al. The incubation period of Coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: estimation and application. Ann Intern Med 2020;(e-pub ahead of print). doi 10.7326/M20-0504
  • 20 Linton NM, Kobayashi T, Yang Y. et al. Incubation period and other epidemiological characteristics of 2019 novel Coronavirus infections with right truncation: a statistical analysis of publicly available case data. J Clin Med 2020; 9 (02) E538
    CrossrefPubMedGoogle Scholar
  • 21 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) doi 10.2807/1560-7917.ES.2020.25.5.2000062
  • 22 Nishiura H, Linton NM, Akhmetzhanov AR. Serial interval of novel coronavirus (COVID-19) infections. Int J Infect Dis 2020; 93: 284-286
    CrossrefPubMedGoogle Scholar
  • 23 Zhang J, Litvinova M, Wang W. et al. Evolving epidemiology and transmission dynamics of coronavirus disease 2019 outside Hubei province, China: a descriptive and modelling study. Lancet Infect Dis 2020; (April): S1473-3099 (20) 30230-9
    Google Scholar
  • 24 Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Meyers LA. Serial interval of COVID-19 among publicly reported confirmed cases. Emerg Infect Dis 2020;26(6doi 10.3201/eid2606.200357
  • 25 To KK-W, Tsang OT-Y, Leung W-S. et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis 2020; (March): S1473-3099 (20) 30196-1
    Google Scholar
  • 26 Wölfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-2019. Nature 2020;(e-pub ahead of print). doi 10.1038/s41586-020-2196-x
  • 27 Zhou F, Yu T, Du R. et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020; 395 (10229) 1054-1062
    CrossrefPubMedGoogle Scholar
  • 28 Liu Y, Yan L-M, Wan L. et al. Viral dynamics in mild and severe cases of COVID-19. Lancet Infect Dis 2020; (March): S1473-3099 (20) 30232-2
    Google Scholar
  • 29 Wu Y, Guo C, Tang L. et al. Prolonged presence of SARS-CoV-2 viral RNA in faecal samples. Lancet Gastroenterol Hepatol 2020; 5 (05) 434-435
    CrossrefPubMedGoogle Scholar
  • 30 Xu K, Chen Y, Yuan J, et al. Factors associated with prolonged viral RNA shedding in patients with COVID-19. Clin Infect Dis 2020;(e-pub ahead of print). doi 10.1093/cid/ciaa351
  • 31 Wei WE, Li Z, Chiew CJ, Yong SE, To MP, Lee VJ. Presymptomatic transmission of SARS-CoV-2 - Singapore, January 23-March 16, 2020. MM. WR Morb Mortal Wkly Rep 2020; 69 (14) 411-415
    Google Scholar
  • 32 Wu Z, McGoogan JM. 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. JAMA 2020;(e-pub ahead of print). doi 10.1001/jama.2020.2648
  • 33 Guan W-J, Ni Z-Y, Hu Y, et al; China Medical Treatment Expert Group for COVID-19. Clinical characteristics of Coronavirus disease 2019 in China. N Engl J Med 2020;(e-pub ahead of print). doi 10.1056/NEJMoa2002032
  • 34 Lechien JR, Chiesa-Estomba CM, De Siati DR, et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID- 19): a multicenter European study. Eur Arch Otorhinolaryngol 2020;(e-pub ahead of print). doi 10.1007/s00405-020-05965-1
  • 35 Wang D, Hu B, Hu C, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel Coronavirus-infected pneumonia in Wuhan, China. JAMA 2020;(e-pub ahead of print). doi 10.1001/jama.2020.1585
  • 36 Cheung KS, Hung IF, Chan PP. et al. Gastrointestinal manifestations of SARS-CoV-2 infection and virus load in fecal samples from the Hong Kong Cohort and systematic review and meta-analysis. Gastroenterology 2020; (April): S0016-5085 (20) 30448-0
    Google Scholar
  • 37 CDC COVID-19 Response Team. Severe outcomes among patients with Coronavirus disease 2019 (COVID-19) - United States, February 12-March 16, 2020. MM. WR Morb Mortal Wkly Rep 2020; 69 (12) 343-346
    Google Scholar
  • 38 Onder G, Rezza G, Brusaferro S. Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy. JAMA 2020;(e-pub ahead of print). doi 10.1001/jama.2020.4683
  • 39 Syal K. COVID-19: herd immunity and convalescent plasma transfer therapy. J Med Virol 2020;(e-pub ahead of print). doi 10.1002/jmv.25870
  • 40 Public statement for collaboration on COVID-19 vaccine development. https://www.who.int/news-room/detail/13-04-2020-public-statement-for-collaboration-on-covid-19-vaccine-development. Accessed April 29, 2020.
  • 41 www.who.int/blueprint/priority-diseases/key-action/novel-coronavirus-landscape-ncov.pdf
  • 42 The Lancet. COVID-19: protecting health-care workers. Lancet Lond Engl 2020; 395 (10228): 922 10.1016/S0140-6736(20)30644-9
    Google Scholar
  • 43 CDC COVID-19 Response Team. Characteristics of Health Care Personnel with COVID-19 - United States, February 12-April 9, 2020. MMWR Morb Mortal Wkly Rep. 2020;69(15):477-481. doi:10.15585/mmwr.mm6915e6
  • 44 Advice for public. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public. Accessed April 18, 2020.