Study population and setting
This study sought to characterize disparities in COVID-19 vaccination rates among US states between urban and rural populations. The study used data reported to the US CDC from December 10, 2020 to April 10, 2021 by health departments, pharmacies, and federal entities in the immunization information systems, the Vaccine Administration Management System, or directly submitted by these entities. County-level data was analyzed for all adults (18 years or older) living in 49 states and DC who received at least one vaccine dose. Hawaii and eight counties in California were excluded due to data-sharing restrictions of county-level information. Individuals receiving their first dose of vaccine were classified as four urban and two rural categories according to their county of residence. Urban counties included large central metropolitan, suburbs (large fringe metro), medium metro, and small metro, while rural was comprised of rural counties (micropolitan), and most rural counties (noncore). Four jurisdictions did not report for rural counties and therefore, 45 jurisdictions were included. Vaccine recipients were stratified by age group (18 to 64, and 65 years+), sex, jurisdiction, and by urban/rural residence.
Summary of Main Findings
Overall, COVID-19 vaccination rates were higher in urban areas (46%) compared to rural (39%). This disparity persisted across all age groups and by sex. In 36 jurisdictions (72% of 45 states and DC), coverage was higher in urban counties, in 5 jurisdictions (10%), it was the same in both rural and urban counties, and in 5 jurisdictions (10%) it was significantly higher among rural counties compared to urban. Nearly all (98%) people were vaccinated in their state of residence, and 67.1% were vaccinated in their county of residence. More individuals in large fringe metropolitan counties (suburban, 14%) and noncore counties (most rural, 15%) reported traveling to nonadjacent counties compared with those in the most urban counties (10%).
The study used county-level data from nearly every state in the US and DC, making it one of the most complete accounts of vaccination in the US. Given anecdotal reports of individuals traveling long distances to receive vaccines, they also disaggregated their findings based on county of residence vs. where individuals were actually vaccinated. Additionally, they disaggregated by major sociodemographic factors (sex and age) in order to identify any differences in disparities there also.
The study used first dose as the outcome of interest, therefore, these findings do not reflect full vaccination rates, which may have even greater disparities. The study was unable to examine race/ethnicity disparities that may be correlated to driving some of these disparities, given this data was missing for 40% of their dataset. The absolute number of individuals were not often reported in their analysis, rather the authors reported the proportion of those vaccinated by their county of residence, adjacent county, and nonadjacent county. This makes it difficult to understand missingness in their data and whether potential selection bias occurred in their findings. Finally, it is unclear what is driving these disparities, and no specific causal factor can be identified from the data analyzed.
Vaccination access among urban vs. rural areas is a major public health issue, and this is the largest study to date from the US directly comparing vaccine coverage in these areas.
This review was posted on: 19 June 2021