key: cord-0693555-po1pib7i
authors: Cuadros, Diego F.; Branscum, Adam J.; Mukandavire, Zindoga; Miller, F. DeWolfe; MacKinnon, Neil
title: Dynamics of the COVID-19 epidemic in urban and rural areas in the United States
date: 2021-04-22
journal: Ann Epidemiol
DOI: 10.1016/j.annepidem.2021.04.007
sha: 151ba5ebf6681bc202843e008382771e8283fa50
doc_id: 693555
cord_uid: po1pib7i

PURPOSE: There is a growing concern about the COVID-19 epidemic intensifying in rural areas in the United States (U.S.). In this study, we described the dynamics of COVID-19 cases and deaths in rural and urban counties in the U.S. METHODS: Using data from April 1 to November 12, 2020, from Johns Hopkins University, we estimated COVID-19 incidence and mortality rates and conducted comparisons between urban and rural areas in three time periods at the national level, and in states with higher and lower COVID-19 incidence rates. RESULTS: Results at the national level showed greater COVID-19 incidence rates in urban compared to rural counties in the Northeast and Mid-Atlantic regions of the U.S. at the beginning of the epidemic. However, the intensity of the epidemic has shifted to a rapid surge in rural areas. In particular, high incidence states located in the Mid-west of the country had more than 3,400 COVID-19 cases per 100,000 people compared to 1,284 cases per 100,000 people in urban counties nationwide during the third period (August 30 to November 12). CONCLUSIONS: Overall, the current epicenter of the epidemic is located in states with higher infection rates and mortality in rural areas. Infection prevention and control efforts including healthcare capacity should be scaled up in these vulnerable rural areas.

 Assessment of the patterns of COVID-19 in rural and urban counties in the United States.

 COVID-19 epidemic in the United States is composed of sub-epidemics with different temporal dynamics and spatial patterns.

 The current epicenter of the epidemic is located in states with higher COVID-19 infection intensity and mortality in rural areas.

 Residents in areas with high burden of infection combined with lower healthcare capacity are at higher risk of COVID-19 infection and related morbidity and mortality.

The United States (U.S.) has the highest number of COVID-19 cases in the world, with 13 ,386,255 confirmed cases as of November 29, 2020 . From the beginning of May to mid-November 2020, the number of confirmed COVID-19 cases in the U.S. has steadily increased, whereas the rate of COVID-19-related hospitalizations and mortality has declined. 1 However, there is substantial spatial and temporal variation in the dynamics of the epidemic within the U.S., [2] [3] [4] with New York, New Jersey and Maryland experiencing the highest burden of the infection early in the epidemic. The epicenter of the disease shifted to the southern U.S. from June to September of 2020, followed by a surge in the Midwest in late September. Furthermore, there is a growing concern about the epidemic worsening in rural areas, which are characterized by lower healthcare capacity, thus placing residents at higher risk of COVID-19 infection and death. [4] [5] [6] Rural areas in the United States face many challenges including lower healthcare resources compared to urban communities. For example, over 4.7 million people live in 460 rural counties across the nation where there are no general medical or surgical hospital beds. In addition, 16.4 million people live in rural areas with no medical/surgical intensive care unit (ICU) beds. 7 Rural residents have a shorter life expectancy than urban residents and rural households also report a lower median income. 8 According to the World Health Organization (WHO), older people are at the highest risk of COVID-19 morbidity and mortality. 9 In the 2016 U.S. Census, the median age of rural area residents was 51 years, whereas the median age in urban areas was 45. 10 Rural communities also have a larger proportion of residents 65 years and older (18.4% compared to 14.5%). 8 The proportion of older adults is increasing more quickly in rural communities due to declining birth rates and migration patterns in younger adults. 11 With rural communities already at a disadvantage in terms of healthcare and population demographics, and with COVID-19 proving to be a more intense burden on older populations, rural areas are in greater danger compared to urban areas. In this study, we estimated COVID-19 incidence and mortality rates to compare urban and rural areas in the U.S. during three time periods in 2020.

COVID-19 data from April 1 to November 12, 2020, obtained from Johns Hopkins University 12 for 3,108 counties in the 48 contiguous U.S. states, were used in our analyses. The study dataset contained records for 10,143,327 COVID-19 cases and 234,186 COVID-19 related deaths. We classified counties as rural or urban based on the 2013 National Center for Health Statistics urban classification methodology. 13 The criteria for metropolitan (urban) counties ranges from small metropolitan areas with population size less than 250,000 people to large metropolitan areas with more than one million people, and nonmetropolitan (rural) counties are those with population less than 50,000. 1,160 counties were classified as urban (blue in Supplementary corresponded to the surge of the third wave of the epidemic in the U.S. To illustrate temporal changes in both COVID-19 incidence and mortality rates, we generated choropleth maps at the county level to compare rates in each period. We also categorized states into two groups based on incidence rates. States in the highest quartile of COVID-19 incidence rates in the third period (that illustrates the current stage of the epidemic at the moment in which the study was conducted) were included in the -higher incidence rate states‖, while the remaining states were included in the -lower incidence rate states‖, and these groups were used as reference to retrospectively generate comparison between groups during the three periods.

To estimate the COVID-19 incidence and mortality rate for each period, we analyzed data on urban and rural cases at the national level as well as by high/low incidence states for each time interval. For example, we calculated the incidence rate in an urban area as the number of cases divided by the population size of the area (with the result reported per 100,000 people), and then calculated a 95% confidence interval for a Poisson rate using an exact method with the -pois.exact‖ function in the R environment. 15 We conducted comparisons of the COVID-19 incidence and mortality rates between urban and rural areas among the three different time intervals at the national level, and in the states with higher and lower COVID-19 incidence rates by computing Poisson rates of COVID-19 incidence (or mortality) for two different time periods. In this analysis it is assumed that (incidence or mortality) counts Y and X at two time 

Rate ratio analyses were conducted using the rateratio.test package in the R environment version 3.5.2. 15 This study followed the guidelines of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) 16 .

There The Table presents estimates of COVID-19 incidence and mortality rates at the national level, as well as for higher and lower incidence rate states for the three periods. Nationally, the COVID-19 incidence rate was higher in urban counties compared to rural counties in the first two periods, but rural counties had the highest incidence rate in the third period. The COVID-19

incidence rate in rural counties increased by over 180% from the first to the second period (rate 

We assessed the patterns of COVID-19 incidence and mortality rates during intervention and post-intervention periods for rural and urban counties in the U.S. Our results suggest that the COVID-19 landscape in the U.S. is dynamic with substantial changes over time and space. people in the first period to more than 1,000 cases in the second period, and contrary to the pattern observed in urban areas, the infection rate continued increasing in rural counties, reaching almost 2,000 cases in the third period.

Reasons for the differential temporal dynamics between urban and rural areas can be manifold.

COVID-19 infection rates were lower on average in rural than in urban counties in the early stages of the epidemic. In large urban areas, the susceptibility driven by high population density and enhanced connectivity forced the implementation of strict non-pharmaceutical interventions such as lockdowns and social distancing practices, which reduced the community spread of infection in these areas. As a result, the pandemic may be showing signs of receding in large metropolitan areas, but continued to diffuse from cities to rural communities, which are communities that might have implemented less intensive interventions. For example effective non-pharmaceutical measures such as face covering have been met with some resistance among rural communities in the U.S. 17 With the slow rollout of vaccination in the country, masks remain one of the few control measures available for protection against the virus as they serve as a physical barrier for virus dispersion. 18 Although mask wearing has been found to be an effective and proactive public health tool against virus dispersion, some studies have identified lower frequency of mask use in public areas in rural compared to urban counties. 17 These studies found that wearing a mask was about four times greater in urban than in rural areas, possibly reflecting a perception of lower risk of COVID-19 infection in rural communities.

Although COVID-19 mortality has declined nationally, this decline was only observed in urban areas, whereas the mortality rate has increased more than 100% from the first to the third period in the rural counties. COVID-19 mortality is steadily declining in urban areas, with the largest decline of 45% from the first to the second period, and with a smaller decline of 30% from the second to the third period. Conversely, mortality rate in rural areas is steadily increasing, with an increase of about 40% from the first to the second period, and with the largest increased occurring between the second to the third period, with about 55% increase in the COVID-19 mortality rate. Reasons for these disparities in the mortality rates between urban and rural areas can be linked to a shift in the demographic groups most affected by the epidemic. Younger populations in urban counties are currently experiencing the largest burden of infection. This demographic group has better infection outcomes, with lower infection complications, hospitalizations, and consequently COVID-19 related deaths. 19 Conversely, many of the risk factors for COVID-19 infection complications are exacerbated in rural areas, particularly in older adults. Rural areas have older populations, 20 on average, with more underlying medical conditions than suburban and urban communities. 21 It is estimated that about 50% of rural residents are at high risk for hospitalization and COVID-19 related complications, compared to 40% in metropolitan areas. In addition, rural populations are older and have lower general health conditions than urban populations, and therefore they are vulnerable populations at higher risk of COVID-19 related hospitalization and deaths, with an estimated 10% higher hospitalization rate for COVID-19 per capita than urban residents given equal infection rates. 22 Additionally, major vulnerabilities in rural areas include fewer physicians and lack of access to intensive care and ventilators, which are key aspects of care needed for the at least 5% of critical COVID-19

infection related complications. 23 Health care facilities within rural communities are typically less well-resourced with reduced access to personal protective equipment, lower access to ICU beds, testing, and the necessary equipment to effectively treat people most severely affected by COVID-19 infection complications, which are commonly older adults. 24 As a result, many rural hospitals find themselves needing to transfer residents with more serious cases of COVID-19 to larger facilities in urban areas for treatment. 25 Hospital transfers require time and that can affect disease outcomes in critical situations, and relocating patients during the current wave of COVID-19 to urban areas may present additional challenges if the receiving hospital is already overwhelmed. 22 As the U.S. begins its massive vaccine rollout, health departments across the country are scrambling to plan and adjust their vaccination plans, often while simultaneously managing a surge in new COVID-19 cases, particularly in rural areas. The geography can also compound disparities in access that affect rural clinics, which face unique challenges to provide vaccinations to residents who live many miles away. Rural communities often run short on resources including cold vaccine storage facilities or healthcare workers to administer vaccines.

Additionally, it has been shown that rural residents are less likely to receive flu shots than residents of urban areas 26 The COVID-19 pandemic has continued to spread, causing many deaths around the world.

Analysis of setting-specific data is paramount in understanding local transmission dynamics of the disease and designing effective public health responses. 2, 27 Our findings suggest that the pandemic in the U.S. is composed of sub-epidemics with different temporal dynamics and spatial patterns that could potentially present challenges in disease control within the country. The disease has manifested itself in different spatial and temporal ways in urban and rural areas. The current epicenter of the epidemic is located in states with higher infection intensity and mortality in rural areas, and higher incidence states are currently experiencing a significant increase in the rate of COVID-19 related deaths in both urban and rural areas.

A high burden of infection combined with lower healthcare capacity in rural areas implies that residents in these vulnerable areas are at higher risk of COVID-19 infection and related morbidity and mortality during the current stage of the epidemic in the U.S. 4, 28 Clinicians and public health policy makers must tailor intervention strategies to suit local needs. Public health policies should take into account county-level interventions and strategies specific to each type of community (urban or rural). When making public health policies, the local government should be aware of, and consider, the differences in COVID-19 spread between urban and rural areas, which will allow more effective disease control. With increasing incidence rates in rural areas, residents must be made aware of their increased risk of infection so they can take personal measures to protect themselves, and Critical Access Hospitals must continue to receive Federal funding, as they are crucial to treating patients in rural areas. Health partnerships must also be made to coordinate data and updates about COVID-19, and to share valuable resources, such as personal protective equipment. Efforts focused on decreasing disease spread and strengthening the healthcare capacity in the vulnerable rural areas would benefit rural communities and limit the spread of COVID-19 disease in the current geographical epicenter of the epidemic in the U.S. Table. COVID-19 incidence and mortality rates in urban and rural counties at the national level, and in states with higher or lower incidence rates. Incidence and mortality rates are reported per 100,000 people with their corresponding confidence interval (CI). COVID-19 incidence rates per 100,000 people in the three periods for rural (bars in black) and urban (bars in red) counties in each state included in the study

Coronavirus Cases Are Rising Sharply, but Deaths Are Still Down

Spatiotemporal transmission dynamics of the COVID-19 pandemic and its impact on critical healthcare capacity

Geographic differences in COVID-19 cases, deaths, and incidence-United States

Disease and healthcare burden of COVID-19 in the United States

Progression of COVID-19 From Urban to Rural Areas in the United States: A Spatiotemporal Analysis of Prevalence Rates. The Journal of Rural Health

A deadly ‗checkerboard': Covid-19's new surge across rural America

Metropolitan/Nonmetropolitan COVID-19 Confirmed Cases and General and ICU Beds.‖ RUPRI Center for Rural Health Policy Analysis. RUPRI Center for Rural Health Policy Analysis

Rural Communities: Age, Income, and Health Status. Rural Health Research RECAP

Statement-Older people are at highest risk from COVID-19, but all must act to prevent community spread

New census data show differences between urban and rural populations

Rural-Urban Differences among Older Adults. The University of Minnesota Rural Health Research Center

Novel Coronavirus COVID-19 (2019-nCoV) Data Repository by Johns Hopkins CSSE

NCHS urban-rural classification scheme for counties: US Department of Health and Human Services, Centers for Disease Control and …; 2014. 14. ESRI. 2019 USA Population Density

R: A Language and Environment for Statistical Computing. 3.5.2 ed. Vienna, Austria: R Foundation for Statistical Computing

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for Reporting Observational Studies

Who is wearing a mask? Gender-, age-, and location-related differences during the COVID-19 pandemic

Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis. The Lancet

Spatial disparities in coronavirus incidence and mortality in the United States: an ecological analysis as of

Rural America At A Glance 2018 Edition

Half of Rural Residents at High Risk of Serious Illness Due to COVID-19, Creating Stress on Rural Hospitals

Millions Of Older Americans Live In Counties With No ICU Beds As Pandemic Intensifies

The COVID-19 pandemic and rural hospitals-adding insult to injury

The Unique Impact of COVID-19 on Older Adults in Rural Areas

What vaccination rates in rural America tell us about the advent of COVID-19 vaccines

Quantifying early COVID-19 outbreak transmission in South Africa and exploring vaccine efficacy scenarios

Rural America's Hospitals are Not Prepared to Protect Older Adults From a Surge in COVID-19 Cases

The authors thank the Johns Hopkins University Center for Systems Science and Engineering, and the Our World in Data project for releasing data on cases and testing for COVID-19.

Dr. Cuadros had full access to all the data in the study and takes responsibility for the integrity of