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Many people are asking...

...why does COVID-19 hit some areas harder than others?

This piece is courtesy of Vanessa Kerry, MD and Bryn Falahee, MSc.
The FLARE Four:
  1. As the COVID-19 outbreak progresses in the U.S., it is becoming clear that communities are not equally affected. 
  2. Racial and socioeconomic disparities in incidence are apparent in highly impacted communities, such as New York and Boston, as well as outside the Northeast, in places like Charlotte, Chicago, and the Navajo Nation. 
  3. In addition to disparate incidence of disease, disadvantaged communities face higher rates of comorbidities such as diabetes and hypertension that are known to contribute to poor outcomes in COVID-19. 
  4. Some of these communities with elevated rates of high-risk health conditions have greater proportions of uninsured residents, which may lead to under-financed and under-resourced healthcare systems, ill-prepared for a COVID-19 patient surge.
Does COVID-19 have a disparate impact on disadvantaged communities?
While it is clear from early clinical data that age and comorbidities including diabetes, heart disease, and COPD are individual risk factors for severe illness or death from COVID-19 (CDC COVID-19 Response Team, 2020a; Zhou et al., 2020), other factors, including poverty and race, have revealed themselves to be strong predictors of COVID-19 morbidity and mortality on the community level. For example:
  • Charlotte, North Carolina is only 33% African American, but African American residents make up roughly 44% of its coronavirus cases (Kuznitz, 2020).
  • In Michigan, African-Americans account for 33% of cases and 40% of deaths in the state, despite making up only 14% of the population (Baker & Snyder, 2020; Coronavirus - Michigan Data, n.d.).
  • Milwaukee County, Wisconsin is only 26% African-American, yet African-Americans account for almost 50% of the coronavirus cases and 80% of the deaths (Baker & Snyder, 2020; Johnson & Buford, 2020). 
  • In Chicago, IL more than 50% of COVID-19 cases and nearly 70% of COVID-19 deaths involve African-American individuals, although African-Americans make up only 30% of the population. A high percentage of Chicago’s deaths are concentrated in only five neighborhoods (Yancy, 2020).
Detailed data from the largest centers of the outbreak in the U.S. confirm the above trends:
New York
A recent map of New York City, published by the NYC Department of Health and Mental Hygiene, showed the number of positive tests per 1,000 population, broken down by zip code (Figure 1). The highest number of positive cases in New York City were in neighborhoods with large immigrant populations and low average incomes. Two areas in Queens, Elmhurst and Corona, led the city in the number of reported SARS-CoV-2 infections (Honan, 2020).
Figure 1: number of positive SARS-CoV-2 tests across NYC zipcodes (Honan, 2020).
More than half of residents in West Queens are Latino, and more than half of residents in Southeast Queens are African American (Citizens’ Committee for the Children of New York, 2020). Additionally, preliminary data on fatalities from the New York State Department of Health shows that deaths from COVID-19 among Hispanic (34%) and African American (28%) patients, are disproportionate to their share of the total population (29% and 22%, respectively) (Citizens’ Committee for the Children of New York, 2020; Workbook: NYS-COVID19-Tracker, n.d.). TIME compared the most recent COVID-19 incidence in New York City with income for each zip code released by the IRS (Figure 2). The analysis revealed that the zip codes in the bottom 25% of average incomes represent 36% of all cases of the disease, while the wealthiest 25% account for under 10% (Wilson, 2020). Moreover, these numbers may actually understate the problem as it is not clear that access to testing is equally distributed (Hicks, 2020; Schmitt-Grohé et al., 2020).
Figure 2: COVID-19 cases by income percentile in NYC (Wilson, 2020).
Recent data published by the state Department of Public Health show that Chelsea (Figure 3), a city of about 40,000 people located in the Boston metro area, has the highest per capita incidence of COVID-19 in the state at a rate of 1,890 per 100,000 people. Statewide, the coronavirus rate is 488 per 100,000 people (COVID-19 Response Reporting, n.d.). Chelsea, the hardest hit community, is 66.9% Hispanic and 18.8% of people live below the poverty line, according to the most recent US census data (U.S. Census Bureau QuickFacts: Chelsea city, Massachusetts, n.d.).
Figure 3: Location of Chelsea and Boston in Suffolk County, Massachusetts. Chelsea is shown in red.
Navajo Nation
The Navajo Nation now has more confirmed cases of COVID-19 per capita than almost every U.S. state. It trails only New York and New Jersey in the number of confirmed cases per capita. As of April 13th, the American Indian nation had recorded 813 infections and 28 deaths linked to COVID-19 on its reservation, making the number of confirmed cases on the reservation about 468 per 100,000 people. As of April 14th, New York and New Jersey had recorded 998 cases and 727 cases per 100,000 people (Miller, 2020). The rising number of cases in the Navajo Nation is especially concerning as Navajo populations are particularly vulnerable to COVID-19 given high rates of diabetes and cardiovascular disease (Poudel et al., 2018). To make matters worse, nearly 40% of residents do not have access to running water or indoor plumbing, making hand washing and other COVID-19 prevention measures more challenging (de Sam Lazaro, 2018).
Why do some areas have more cases than others?
The high incidence in these different areas is being driven by a number of factors: 
Density: The CDC considers population density as one of the determinants in the geographic differences in COVID-19 incidence (CDC COVID-19 Response Team, 2020b). Chelsea, MA has a high population density. The city is a mere 1.8 square miles total and one of the densest communities in Massachusetts with over 22,000 people-per-square-mile — (approximately three times higher than the rate in Boston). This density means that when someone is sick, they are not able to isolate themselves as easily. 
However, density alone is not the whole story…
Nearby cities such as Somerville and Cambridge, also located in the Boston area have a greater population density, but much higher per capita income and lower infection rates (Massachusetts Snapshot: Population density 2011, n.d.). 
Employment in essential jobs: Many of the residents in areas with high infection rates work in industries considered “essential services” and thus are unable to work from home (Communities of Color at Higher Risk for Health and Economic Challenges due to COVID-19 - Issue Brief, 2020). Workers in “essential services” may be at higher risk for COVID-19 exposure through their work.
Multigenerational households: An increased proportion of elders living with adult children has been implicated in the relatively higher case fatality rates seen in Italy and Spain compared to other European countries (Goodman & Bubola, 2020; Stancati, 2020). Minority Americans are more likely to live in multigenerational households, with 29% of Asian Americans, 27% of Latinos, and 26% of African Americans living in a home with two or more adult generations under one roof, compared to 16% of Whites in 2016 (Pew Research Center, n.d.). This may disproportionately expose minority American elders and extended families to risk from children who leave the home to work. 
Language: Some areas of the Navajo Nation, parts of New York, and the city of Chelsea have a large non-English speaking (or English as a second language) population which may modify health outcomes. Several studies have shown previously that patients with limited English proficiency have poorer health outcomes (Kim et al., 2017), and worse access to healthcare (Leung et al., 2018). Compounding these disadvantages, limitations on in-person interpreting in the healthcare setting may leave patients with limited English proficiency without consistent access to a medical interpreter (Aguilera, Originally published: April 13, 2020).
Healthcare avoidance: There is widespread, though difficult to document, concern that patients from disproportionately-affected communities may have more severe disease at presentation and may go untested due to distrust of the medical community stemming from past mistreatment (Jacobs et al., 2006). In the case of potentially undocumented patients, there may be fear of legal repercussions for seeking medical care (Hacker et al., 2015). 
Air pollution: Greater Boston (including Chelsea) and NYC are both in areas of higher exposure to fine particulate matter than many other communities. Some data suggests that increased air pollution correlates with increased mortality in COVID-19 (Wu et al., n.d.), and in SARS (Figure 4, Cui et al., 2003), although causation has not been definitively determined. 
Figure 4: Top panel shows county level 17-year long-term average of PM2.5 concentrations (2000-2016) in g/m3. Bottom panel shows county level number of COVID-19 deaths per one million population through April 4, 2020 (Wu et al., n.d.).
Healthcare policy: The sine qua non of caring for patients generally and a population with COVID-19 is access to healthcare. The geographic and racial disparities described above for COVID-19 incidence parallel geographic and racial disparities in healthcare access. Decreased healthcare access both increases an individual patient's likelihood of severe disease and decreases the ability of the healthcare system to deal with a surge of cases.
Health insurance and incidence of comorbidities
Southern states are poorer, on average (Artiga, 2016), and less likely to have participated in Medicaid expansion under the Affordable Care Act (Figure 5, (Status of State Medicaid Expansion Decisions: Interactive Map, 2020). Thus, large portions of the population lack access to high quality doctors and hospitals (The Century Foundation, 2019). A recent analysis from the Kaiser Family Foundation shows that in many southern states, a significantly higher proportion of the population is at risk for severe COVID-19 due to the predominance of underlying health conditions (definition of high risk includes: age 65+, adults between the ages of 18 and 64 with heart disease, COPD, uncontrolled asthma, diabetes, or a BMI greater than 40). In some places, this exceeds 40% of the adult population (Koma et al., 2020) (Figure 6).
In the United States, cost is a major barrier to healthcare access. A Gallup poll from 2019 showed that a record 25% of Americans said they or a family member put off treatment for a serious medical condition in the past year because of the cost (Saad, 2019). One of the major conduits for accessing healthcare for lower income populations is through Medicaid. The overlap between states with a large fraction of high-risk patients and the states who chose to not expand Medicaid under the Affordable Care Act is striking (Figure 5, (Status of State Medicaid Expansion Decisions: Interactive Map, 2020). With millions of people filing for unemployment in the last 8 weeks comes a massive loss of employer-sponsored insurance, making Medicaid coverage an even more crucial safety net during COVID-19 (Luthra et al., 2020; Rainey & McCaskill, n.d.).
Figure 5: Status of State Action on the Medicaid Expansion
Status of State Medicaid Expansion Decisions: Interactive Map, 2020).
Figure 6: Share of adults at higher risk of serious illness if infected with SARS-CoV-2 (Koma et al., 2020).
In fact, as COVID-19 began to spread across the US, the Centers for Medicare & Medicaid Services (CMS) urged Medicaid expansion to improve insurance coverage rates. CMS relaxed certain bureaucratic barriers to expedite enrollment, and also opened up opportunities for states to expand their Medicaid programs (Waddill, 2020).
A study published this January in Health Affairs showed that Medicaid expansion slowed rates of health decline for low-income adults in southern states (Graves et al., 2020). Therefore, a failure to expand Medicaid may have put populations more at risk for worse health outcomes, increasing their risk of serious illness if infected with SARS-CoV-2.
Healthcare system preparedness for COVID-19
There is concern that many states that did not expand Medicaid do not have the resources or systems in place to deal with the expected surge in COVID-19-related patient volume. COVID-19 patient surge may further exacerbate healthcare inequities (Rainey & McCaskill, n.d.). Lack of access to health insurance has implications for hospitals’ financial stability, as well as for the health of an individual patient. Expansion of insurance access reduces uncompensated care expenditures. Large expenditures on uncompensated care can, in fact lead to hospital closures. A study by Lindrooth and colleagues (Lindrooth et al., 2018) compared rates of hospital closures in states that did and did not participate in Medicaid expansion and found a lower rate of closures in expansion states (Figure 7).
Fig 7: Unadjusted hospital closure rates by state Medicaid expansion status, 2008-2016 (Lindrooth 2018).
To the extent that future centers of the U.S. outbreak occur in states with low rates of healthcare access, there is concern about the resilience of local healthcare systems. A recent report indicates that more than half of U.S. counties have no ICU beds (Schulte et al., 2020) (Figure 8).
Figure 8: Comparison of ICU bed availability across US hospitals by counties (Schulte et al., 2020).
While everyone is at risk, the virus’s toll also exposes the underlying inequities in our health and social systems that force some to bear a greater burden of risk. As we develop better science and medical innovations to combat the current pandemic, it is equally important to modify the social structures and health systems that place vulnerable communities at risk of poor health. Indeed, action to improve these social determinants of health is likely to have a far greater impact on COVID-19 than anything that we can do in the ICU.
FLARE is a collaborative effort within the Pulmonary and Critical Care Division and the Department of Medicine at Massachusetts General Hospital. Its mission is to appraise the rapidly evolving literature on SARS-CoV-2 with a focus on critical care issues.

Prior FLAREs can be found here.
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  • Aguilera, J. (Originally published: April 13, 2020). Coronavirus Patients Who Don’t Speak English Could End Up “Unable to Communicate in Their Last Moments of Life.” Time.
  • Artiga, S. (2016, February 10). Health and Health Coverage in the South: A Data Update. The Henry J. Kaiser Family Foundation.
  • Baker, S., & Snyder, A. (2020, April 4). Poor and minority communities are bearing the brunt of the coronavirus pain. Axios.
  • CDC COVID-19 Response Team. (2020a). Preliminary Estimates of the Prevalence of Selected Underlying Health Conditions Among Patients with Coronavirus Disease 2019—United States, February 12–March 28, 2020.
  • CDC COVID-19 Response Team. (2020b). Geographic Differences in COVID-19 Cases, Deaths, and Incidence - United States, February 12-April 7, 2020. MMWR. Morbidity and Mortality Weekly Report, 69(15), 465–471.
  • Citizens’ Committee for the Children of New York. (2020). COVID-19 in New York City: Understanding the Hardest Hit Communities.
  • Communities of Color at Higher Risk for Health and Economic Challenges due to COVID-19 - Issue Brief. (2020, April 7). The Henry J. Kaiser Family Foundation.
  • Coronavirus - Michigan Data. (n.d.). Retrieved Accessed April 5, 2020, from,9753,7-406-98163_98173---,00.html
  • COVID-19 Response Reporting. (n.d.). Retrieved April 21, 2020, from
  • Cui, Y., Zhang, Z.-F., Froines, J., Zhao, J., Wang, H., Yu, S.-Z., & Detels, R. (2003). Air pollution and case fatality of SARS in the People’s Republic of China: an ecologic study. Environmental Health: A Global Access Science Source, 2(1), 15.
  • de Sam Lazaro, F. (2018, June 20). How off-the-grid Navajo residents are getting running water. PBS NewsHour; PBS NewsHour.
  • Goodman, P. S., & Bubola, E. (2020, April 8). Are Adults Living With Parents Making the Pandemic More Deadly? The New York Times.
  • Graves, J. A., Hatfield, L. A., Blot, W., Keating, N. L., & McWilliams, J. M. (2020). Medicaid Expansion Slowed Rates Of Health Decline For Low-Income Adults In Southern States. Health Affairs , 39(1), 67–76.
  • Hacker, K., Anies, M., Folb, B. L., & Zallman, L. (2015). Barriers to health care for undocumented immigrants: a literature review. Risk Management and Healthcare Policy, 8, 175–183.
  • Hicks, N. (2020, April 17). Most NYC coronavirus testing done in whitest and wealthiest ZIP codes. New York Post; New York Post.
  • Honan, K. (2020, April 2). The New York Neighborhoods With the Most Coronavirus Cases. WSJ Online.
  • Jacobs, E. A., Rolle, I., Ferrans, C. E., Whitaker, E. E., & Warnecke, R. B. (2006). Understanding African Americans’ views of the trustworthiness of physicians. Journal of General Internal Medicine, 21(6), 642–647.
  • Johnson, A., & Buford, T. (2020, April 3). Early Data Shows African Americans Have Contracted and Died of Coronavirus at an Alarming Rate — ProPublica. ProPublica.
  • Kim, E. J., Kim, T., Paasche-Orlow, M. K., Rose, A. J., & Hanchate, A. D. (2017). Disparities in Hypertension Associated with Limited English Proficiency. Journal of General Internal Medicine, 32(6), 632–639.
  • Koma, W., Neuman, T., Claxton, G., Rae, M., Kates, J., & Michaud, J. (2020, April 1). How Many Adults Are at Risk of Serious Illness If Infected with Coronavirus? Updated Data. The Henry J. Kaiser Family Foundation.
  • Kuznitz, A. (2020, March 30). High case count among black residents in Mecklenburg a “major problem,” some leaders say. Charlotteobserver; Charlotte Observer.
  • Leung, L. B., Vargas-Bustamante, A., Martinez, A. E., Chen, X., & Rodriguez, H. P. (2018). Disparities in Diabetes Care Quality by English Language Preference in Community Health Centers. Health Services Research, 53(1), 509–531.
  • Lindrooth, R. C., Perraillon, M. C., Hardy, R. Y., & Tung, G. J. (2018). Understanding The Relationship Between Medicaid Expansions And Hospital Closures. Health Affairs , 37(1), 111–120.
  • Luthra, S., Galewitz, P., & Bluth, R. (2020, April 3). Medicaid Nearing “Eye Of The Storm” As Newly Unemployed Look For Coverage. Kaiser Health News.
  • Miller, H. (2020, April 14). Navajo Nation Reports More Coronavirus Cases Per Capita Than All But 2 U.S. States. HuffPost; HuffPost.
  • Pew Research Center. (n.d.). Record 64 million Americans live in multigenerational households. Pew Research Center. Retrieved April 21, 2020, from
  • Poudel, A., Zhou, J. Y., Story, D., & Li, L. (2018). Diabetes and Associated Cardiovascular Complications in American Indians/Alaskan Natives: A Review of Risks and Prevention Strategies. Journal of Diabetes Research, 2018, 2742565.
  • Rainey, R., & McCaskill, N. (n.d.). ’No words for this’: 10 million workers file jobless claims in just two weeks. POLITICO. Retrieved April 21, 2020, from
  • Saad, L. (2019, September 12). More Americans Delaying Medical Treatment Due to Cost.; Gallup.
  • Schmitt-Grohé, S., Teoh, K., & Uribe, M. (2020). Covid-19: Testing Inequality in New York City (No. 27019). National Bureau of Economic Research.
  • Schulte, F., Lucas, E., Rau, J., Szabo, L., & Hancock, J. (2020, March 20). Millions Of Older Americans Live In Counties With No ICU Beds As Pandemic Intensifies. Kaiser Health News.
  • Stancati, M. (2020, March 24). Family Is Italy’s Great Strength. Coronavirus Made It Deadly. WSJ Online.
  • Status of State Medicaid Expansion Decisions: Interactive Map. (2020, March 13). The Henry J. Kaiser Family Foundation.
  • The Century Foundation. (2019, December 19). Racism, Inequality, and Health Care for African Americans. The Century Foundation.
  • U.S. Census Bureau QuickFacts: Chelsea city, Massachusetts. (n.d.). US Census Bureau. Retrieved April 21, 2020, from
  • Waddill, K. (2020, March 16). CMS Urges Medicaid Expansion Amid Coronavirus Emergency. HealthPayerIntelligence.
  • Wilson, C. (2020, April 15). These Graphs Show How COVID-19 Is Ravaging New York City’s Low-Income Neighborhoods. Time.
  • Workbook: NYS-COVID19-Tracker. (n.d.). Retrieved April 21, 2020, from
  • Wu, X., Nethery, R. C., Sabath, B. M., Braun, D., & Dominici, F. (n.d.). Exposure to air pollution and COVID-19 mortality in the United States.
  • Yancy, C. W. (2020). COVID-19 and African Americans. JAMA: The Journal of the American Medical Association.
  • Zhou, F., Yu, T., Du, R., Fan, G., Liu, Y., Liu, Z., Xiang, J., Wang, Y., Song, B., Gu, X., Guan, L., Wei, Y., Li, H., Wu, X., Xu, J., Tu, S., Zhang, Y., Chen, H., & Cao, B. (2020). Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. The Lancet, 395(10229), 1054–1062.

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