COVID-19 epidemiology and demographics

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Sabawoon Mirwais, M.B.B.S, M.D.[2]


The WHO has declared COVID-19 a pandemic. Due to the lack of broad screening that includes the general population (including asymptomatic patients) and the lack of PCR and antibody tests with acceptable sensitivity and specificity, an accurate estimate of the incidence rate of coronavirus disease 2019 (COVID-19) cannot be accurately estimated. The role of symptomatic and asymptomatic transmission continues to be debated. Due to limited testing of asymptomatic individuals, the potential inaccuracies of early PCR tests and antibody tests, the inconsistent reporting and lack of organized data, an accurate case-fatality rate of COVID-19 have yet to be established. The middle-aged and elderly population seems to be the most commonly affected with a median age of 49 - 56 years. COVID-19 has affected males more often than females. While the majority of COVID-19 cases were first reported in China, at this point the disease has spread to all the continents of the world.

Epidemiology and Demorgraphics



Case-fatality rate

  • Due to limited testing of asymptomatic individuals, the potential inaccuracies of early PCR tests and antibody tests, the inconsistent reporting and lack of organized data, an accurate case-fatality rate of COVID-19 has yet to be established.
  • The case fatality-rate of COVID-19 in the first 99 patients at a Wuhan hospital (the epicenter of the outbreak) was found to be 11% but this is likely an overestimate as it only included symptomatic cases.[3]
  • In a different study comprising of 138 patients infected with COVID-19, the mortality was 4.3%, but again this does not include asymptomatic cases.[4]
  • In Wuhan, the case-fatality was 5.8% while in the rest of China it was 0.7%. Again these numbers do not include asymptomatic cases.
  • The CDC states "Lower estimates [0.6%] might be closest to the true value, but a broad range of 0.25%–3.0% probably should be considered."[5]


  • COVID-19 can affect individuals of any age.
  • The middle-aged and elderly population seem to be the most commonly affected.
  • In multiple cohorts of patients hospitalized with confirmed COVID-19, the median age ranges from 49 to 56 years.[6][7][8]
  • In a report including approximately 44,500 cases, 87% of the patients were between the ages of 30 and 79 years.[9]
  • According to the same report mentioned above, 2% of the patients were younger than the age of 20 years.
  • Children account for < 2% of COVID19 possibly due to lower expression of angiotensin-converting enzyme 2 (ACE2) in the respiratory system and other organs, the receptor the virus uses for entry into cells. ACE2 gene expression in the nasal epithelium is now shown to be lower as age decreased. This hypothesis has now found some support in this study showing children have lower ACE2 gene expression in the nasal epithelium, but the causal role has yet to be firmly established. More data is needed but this is provocative[10]

Racial predilection to COVID-19

  • In Baltimore/DC area, the COVID19 positivity rate for Latino patients was 42.6%, significantly higher than the rate for white patients (8.8%), black patients (17.6%), or those of other race/ethnicity (17.2%) (P < .001 for each pairwise comparison)[11]



  • The majority of the early cases of COVID-19 were first reported in China and at this point, the disease has spread to all the continents of the world.
  • In the United States, confirmed cases of COVID-19 have been reported in all of the 50 States.[14]
  • For real-time details regarding the worldwide spread of COVID-19, click here.[1]
  • For real-time details regarding the spread of COVID-19 in the US, click here.[15]


  1. 1.0 1.1 Dong, Ensheng; Du, Hongru; Gardner, Lauren (2020). "An interactive web-based dashboard to track COVID-19 in real time". The Lancet Infectious Diseases. doi:10.1016/S1473-3099(20)30120-1. ISSN 1473-3099.
  2. Spellberg, Brad; Haddix, Meredith; Lee, Rebecca; Butler-Wu, Susan; Holtom, Paul; Yee, Hal; Gounder, Prabhu (2020). "Community Prevalence of SARS-CoV-2 Among Patients With Influenzalike Illnesses Presenting to a Los Angeles Medical Center in March 2020". JAMA. doi:10.1001/jama.2020.4958. ISSN 0098-7484.
  3. Huang, Chaolin; Wang, Yeming; Li, Xingwang; Ren, Lili; Zhao, Jianping; Hu, Yi; Zhang, Li; Fan, Guohui; Xu, Jiuyang; Gu, Xiaoying; Cheng, Zhenshun; Yu, Ting; Xia, Jiaan; Wei, Yuan; Wu, Wenjuan; Xie, Xuelei; Yin, Wen; Li, Hui; Liu, Min; Xiao, Yan; Gao, Hong; Guo, Li; Xie, Jungang; Wang, Guangfa; Jiang, Rongmeng; Gao, Zhancheng; Jin, Qi; Wang, Jianwei; Cao, Bin (2020). "Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China". The Lancet. doi:10.1016/S0140-6736(20)30183-5. ISSN 0140-6736.
  4. Wang, Dawei; Hu, Bo; Hu, Chang; Zhu, Fangfang; Liu, Xing; Zhang, Jing; Wang, Binbin; Xiang, Hui; Cheng, Zhenshun; Xiong, Yong; Zhao, Yan; Li, Yirong; Wang, Xinghuan; Peng, Zhiyong (2020). "Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus–Infected Pneumonia in Wuhan, China". JAMA. doi:10.1001/jama.2020.1585. ISSN 0098-7484.
  5. Wilson, Nick; Kvalsvig, Amanda; Barnard, Lucy Telfar; Baker, Michael G. (2020). "Case-Fatality Risk Estimates for COVID-19 Calculated by Using a Lag Time for Fatality". Emerging Infectious Diseases. 26 (6). doi:10.3201/eid2606.200320. ISSN 1080-6040.
  6. Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, Zhang L, Fan G, Xu J, Gu X, Cheng Z, Yu T, Xia J, Wei Y, Wu W, Xie X, Yin W, Li H, Liu M, Xiao Y, Gao H, Guo L, Xie J, Wang G, Jiang R, Gao Z, Jin Q, Wang J, Cao B (February 2020). "Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China". Lancet. 395 (10223): 497–506. doi:10.1016/S0140-6736(20)30183-5. PMID 31986264.
  7. Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, Qiu Y, Wang J, Liu Y, Wei Y, Xia J, Yu T, Zhang X, Zhang L (February 2020). "Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study". Lancet. 395 (10223): 507–513. doi:10.1016/S0140-6736(20)30211-7. PMID 32007143 Check |pmid= value (help).
  8. Wang D, Hu B, Hu C, Zhu F, Liu X, Zhang J, Wang B, Xiang H, Cheng Z, Xiong Y, Zhao Y, Li Y, Wang X, Peng Z (February 2020). "Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China". JAMA. doi:10.1001/jama.2020.1585. PMID 32031570 Check |pmid= value (help).
  9. Wu Z, McGoogan JM (February 2020). "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. doi:10.1001/jama.2020.2648. PMID 32091533 Check |pmid= value (help).
  10. Bunyavanich, Supinda; Do, Anh; Vicencio, Alfin (2020). "Nasal Gene Expression of Angiotensin-Converting Enzyme 2 in Children and Adults". JAMA. 323 (23): 2427. doi:10.1001/jama.2020.8707. ISSN 0098-7484.
  11. Martinez, Diego A.; Hinson, Jeremiah S.; Klein, Eili Y.; Irvin, Nathan A.; Saheed, Mustapha; Page, Kathleen R.; Levin, Scott R. (2020). "SARS-CoV-2 Positivity Rate for Latinos in the Baltimore-Washington, DC Region". JAMA. doi:10.1001/jama.2020.11374. ISSN 0098-7484.
  12. Li, Qun; Guan, Xuhua; Wu, Peng; Wang, Xiaoye; Zhou, Lei; Tong, Yeqing; Ren, Ruiqi; Leung, Kathy S.M.; Lau, Eric H.Y.; Wong, Jessica Y.; Xing, Xuesen; Xiang, Nijuan; Wu, Yang; Li, Chao; Chen, Qi; Li, Dan; Liu, Tian; Zhao, Jing; Liu, Man; Tu, Wenxiao; Chen, Chuding; Jin, Lianmei; Yang, Rui; Wang, Qi; Zhou, Suhua; Wang, Rui; Liu, Hui; Luo, Yinbo; Liu, Yuan; Shao, Ge; Li, Huan; Tao, Zhongfa; Yang, Yang; Deng, Zhiqiang; Liu, Boxi; Ma, Zhitao; Zhang, Yanping; Shi, Guoqing; Lam, Tommy T.Y.; Wu, Joseph T.; Gao, George F.; Cowling, Benjamin J.; Yang, Bo; Leung, Gabriel M.; Feng, Zijian (2020). "Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia". New England Journal of Medicine. doi:10.1056/NEJMoa2001316. ISSN 0028-4793.
  13. Yang, Yongshi; Peng, Fujun; Wang, Runsheng; Guan, Kai; Jiang, Taijiao; Xu, Guogang; Sun, Jinlyu; Chang, Christopher (2020). "The deadly coronaviruses: The 2003 SARS pandemic and the 2020 novel coronavirus epidemic in China". Journal of Autoimmunity: 102434. doi:10.1016/j.jaut.2020.102434. ISSN 0896-8411.
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