COVID-19 risk factors

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Sara Haddadi, M.D.[2] Sabawoon Mirwais, M.B.B.S, M.D.[3] Aisha Adigun, B.Sc., M.D.[4]


Front-line health-care workers are at increased risk of having a positive Coronavirus disease 2019 (COVID-19) test. Similar to all viral illnesses, exposure is considered the most significant risk factor for infection with SARS-CoV-2 that causes COVID-19. Racial and ethnic minority groups are at increased risk of the infection. The most common risk factors associated with a severe form of the disease include elderly (those aged 60+), male sex, cardiovascular disease, diabetes mellitus, chronic kidney disease, COPD, hypertension, Cancer, Solid organ transplantation, Sickle cell disease, and Obesity (BMI > 30).

Risk Factors

A recent study showed that front-line health-care workers were at increased risk of having a positive COVID-19 test (adjusted HR 3·40, 95% CI 3·37–3·43). Adequacy of PPE, clinical setting, and ethnic background were important factors for a higher positive test result in this group.[1]

Risk Factors Associated with Increased Risk of Infection

Similar to all viral illnesses, exposure is considered the most significant risk factor for infection with Coronavirus disease 2019 (COVID-19). According to CDC, racial and ethnic minority groups are at increased risk of getting sick and dying from COVID-19 [2]

  • Discrimination: Unfortunately, discrimination exists in systems meant to protect well-being or health. Examples of such systems include health care, housing, education, criminal justice, and finance.[2]
  • Healthcare access and utilization: People from some racial and ethnic minority groups are more likely to be uninsured than non-Hispanic whites.[2]
  • Occupation: People from some racial and ethnic minority groups are disproportionately represented in essential work settings such as healthcare facilities, farms, factories, grocery stores, and public transportation. Chances to be exposed to the SARS-CoV-2 virus.[2]
  • Educational, income, and wealth gaps: People with limited job options likely have less flexibility to leave jobs that may put them at a higher risk of exposure. They often cannot afford to miss work, even if they’re sick.[2]
  • Housing: Some people from racial and ethnic minority groups live in crowded conditions that make it more challenging to follow prevention strategies.[2]
    • Culture: In some cultures, it is common for family members of many generations to live in one household.[2]
    • unemployment rates for some racial and ethnic minority groups during the pandemic may lead to a greater risk of eviction and homelessness or sharing of housing.[2]

Risk Factors Associated with Increased Risk of Mortality and Severity of the Disease

  • CDC has published the following conditions listed in the table below as the risk factors for a severe COVID-19. These conditions are categorized into the following groups based on the current evidence:[14][15]
  1. Strongest and most consistent evidence: define as consistent evidence from multiple small studies or a strong association from a large study are categorized. They increase the severity of COVID-19 regardless of the individual's age
  2. Mixed evidence: Defined as multiple studies that reached different conclusions about the risk associated with a condition
  3. Limited evidence: Defined as consistent evidence from a small number of studies. Limited evidence: Defined as consistent evidence from a small number of studies.
underlying medical conditions that increase a person’s risk of severe illness from COVID-19
Level of Evidence Condition
Strongest and Most Consistent Evidence
Mixed Evidence
Limited Evidence

This list is a living document that will be periodically updated, and it could rapidly change as the science evolves.


  1. Nguyen, Long H; Drew, David A; Graham, Mark S; Joshi, Amit D; Guo, Chuan-Guo; Ma, Wenjie; Mehta, Raaj S; Warner, Erica T; Sikavi, Daniel R; Lo, Chun-Han; Kwon, Sohee; Song, Mingyang; Mucci, Lorelei A; Stampfer, Meir J; Willett, Walter C; Eliassen, A Heather; Hart, Jaime E; Chavarro, Jorge E; Rich-Edwards, Janet W; Davies, Richard; Capdevila, Joan; Lee, Karla A; Lochlainn, Mary Ni; Varsavsky, Thomas; Sudre, Carole H; Cardoso, M Jorge; Wolf, Jonathan; Spector, Tim D; Ourselin, Sebastien; Steves, Claire J; Chan, Andrew T; Albert, Christine M.; Andreotti, Gabriella; Bala, Bijal; Balasubramanian, Bijal A.; Beane-Freeman, Laura E.; Brownstein, John S.; Bruinsma, Fiona J.; Coresh, Joe; Costa, Rui; Cowan, Annie N.; Deka, Anusila; Deming-Halverson, Sandra L.; Elena Martinez, Maria; Ernst, Michael E.; Figueiredo, Jane C.; Fortuna, Pedro; Franks, Paul W.; Freeman, Laura Beane; Gardner, Christopher D.; Ghobrial, Irene M.; Haiman, Christopher A.; Hall, Janet E.; Kang, Jae H.; Kirpach, Brenda; Koenen, Karestan C.; Kubzansky, Laura D.; Lacey, Jr, James V.; Le Marchand, Loic; Lin, Xihong; Lutsey, Pam; Marinac, Catherine R.; Martinez, Maria Elena; Milne, Roger L.; Murray, Anne M.; Nash, Denis; Palmer, Julie R.; Patel, Alpa V.; Pierce, Eric; Robertson, McKaylee M.; Rosenberg, Lynn; Sandler, Dale P.; Schurman, Shepherd H.; Sewalk, Kara; Sharma, Shreela V.; Sidey-Gibbons, Christopher J.; Slevin, Liz; Smoller, Jordan W..; Steves, Claire J.; Tiirikainen, Maarit I.; Weiss, Scott T.; Wilkens, Lynne R.; Zhang, Feng (2020). "Risk of COVID-19 among front-line health-care workers and the general community: a prospective cohort study". The Lancet Public Health. doi:10.1016/S2468-2667(20)30164-X. ISSN 2468-2667.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "Health Equity Considerations and Racial and Ethnic Minority Groups | CDC".
  3. Missing or empty |title= (help)
  4. 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.
  5. Heymann, David L; Shindo, Nahoko (2020). "COVID-19: what is next for public health?". The Lancet. 395 (10224): 542–545. doi:10.1016/S0140-6736(20)30374-3. ISSN 0140-6736.
  6. Missing or empty |title= (help)
  7. Hu, Zhiliang; Song, Ci; Xu, Chuanjun; Jin, Guangfu; Chen, Yaling; Xu, Xin; Ma, Hongxia; Chen, Wei; Lin, Yuan; Zheng, Yishan; Wang, Jianming; Hu, Zhibin; Yi, Yongxiang; Shen, Hongbing (2020). "Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China". Science China Life Sciences. doi:10.1007/s11427-020-1661-4. ISSN 1674-7305.
  8. Porcheddu, Rossella; Serra, Caterina; Kelvin, David; Kelvin, Nikki; Rubino, Salvatore (2020). "Similarity in Case Fatality Rates (CFR) of COVID-19/SARS-COV-2 in Italy and China". The Journal of Infection in Developing Countries. 14 (02): 125–128. doi:10.3855/jidc.12600. ISSN 1972-2680.
  9. Wilder-Smith, Annelies; Chiew, Calvin J; Lee, Vernon J (2020). "Can we contain the COVID-19 outbreak with the same measures as for SARS?". The Lancet Infectious Diseases. doi:10.1016/S1473-3099(20)30129-8. ISSN 1473-3099.
  10. Nasiri, Mohammad Javad; Haddadi, Sara; Tahvildari, Azin; Farsi, Yeganeh; Arbabi, Mahta; Hasanzadeh, Saba; Jamshidi, Parnian; Murthi, Mukunthan; Mirsaeidi, Mehdi (2020). "COVID-19 Clinical Characteristics, and Sex-Specific Risk of Mortality: Systematic Review and Meta-Analysis". Frontiers in Medicine. 7. doi:10.3389/fmed.2020.00459. ISSN 2296-858X.
  11. 11.0 11.1 11.2 Williamson, Elizabeth J.; Walker, Alex J.; Bhaskaran, Krishnan; Bacon, Seb; Bates, Chris; Morton, Caroline E.; Curtis, Helen J.; Mehrkar, Amir; Evans, David; Inglesby, Peter; Cockburn, Jonathan; McDonald, Helen I.; MacKenna, Brian; Tomlinson, Laurie; Douglas, Ian J.; Rentsch, Christopher T.; Mathur, Rohini; Wong, Angel Y. S.; Grieve, Richard; Harrison, David; Forbes, Harriet; Schultze, Anna; Croker, Richard; Parry, John; Hester, Frank; Harper, Sam; Perera, Rafael; Evans, Stephen J. W.; Smeeth, Liam; Goldacre, Ben (2020). "OpenSAFELY: factors associated with COVID-19 death in 17 million patients". Nature. doi:10.1038/s41586-020-2521-4. ISSN 0028-0836.
  12. Yancy, Clyde W. (2020). "COVID-19 and African Americans". JAMA. 323 (19): 1891. doi:10.1001/jama.2020.6548. ISSN 0098-7484.
  13. "Low plasma 25(OH) vitamin D level is associated with increased risk of COVID‐19 infection: an Israeli population‐based study - Merzon - - The FEBS Journal - Wiley Online Library".
  14. (PDF) Missing or empty |title= (help)
  15. "Scientific Evidence for Conditions that Increase Risk of Severe Illness | COVID-19 | CDC".