USC researchers are launching a major reboot of their pharmacy desert mapping tool - at a time of accelerating pharmacy closures nationwide - in hopes of protecting the public's access to essential medicines like insulin, antibiotics, contraceptives and flu shots.
"Pharmacies are a vital part of the health care landscape, but we're seeing more closures every day. Ensuring that pharmacies remain accessible - particularly in neighborhoods that need them most - is crucial for promoting health equity," USC's Dima Mazen Qato said. "When pharmacies close, people lose access to essential medications, which can worsen chronic conditions and increase health disparities, especially in historically marginalized areas that already face systemic barriers."
Pharmacy deserts are areas where pharmacies are sparse, making it difficult for residents to access medications. The result is people have to take days off work to pick up medications, skip doses or stop taking the drug entirely.
Currently, 1 in 8 neighborhoods in the United States lack convenient access to pharmacy services. A study led by Qato found an unprecedented decline in the number of pharmacies began in 2018, primarily driven by industry consolidation. Large chains such as CVS, Rite Aid and Walgreens have closed hundreds of stores, and independent pharmacies also are shutting down at a high rate. The trend is compounded by the merging of large pharmacy chains with dominant pharmacy benefit managers (PBMs), which negotiate prescription drug benefits and steer patients to preferred pharmacies.
"We need leaders at every level to use this data to protect these lifeline pharmacies before more neighborhoods are in crisis," said Douglas Hoey, CEO of the National Community Pharmacists Association, which represents some 19,000 independent pharmacies. "When you lose your local pharmacy, you lose more than a place to fill prescriptions - you lose a trusted health advisor, a medication safety expert and often the most accessible health care provider in the community."
Bringing visibility to pharmacy access
The pharmacy desert tool, first launched in 2022, is a collaborative effort across the USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, the USC Dornsife College of Letters, Arts and Sciences and the industry organization. Qato, the Hygeia Centennial Chair and associate professor at USC Mann and a senior scholar at the USC Schaeffer Center for Health Policy & Economics, worked with Associate Professor Robert Vos and doctoral candidate Jeffrey Rozelle from Spatial Sciences Institute at USC Dornsife to build the tool.
It has been accessed by county and state health departments to plan for the impact of pharmacy closures and justify the development of new publicly funded models for pharmacies, Qato said. It has also been used by the Federal Trade Commission and attorney general offices across the country to better understand changes in pharmacy access at the state and local levels.
USC Mann used it to help identify a location for a USC-run community pharmacy in South Los Angeles, on track to open next year. That location, near the intersection of Slauson Avenue and Crenshaw Boulevard, became a shortage area in 2024 after a Rite Aid pharmacy closed. The population there is majority Black, with nearly 20% of residents age 65 or older.
The revamped version of the mapping tool allows users to create an account, zoom into a neighborhood and look through multiple years to see pharmacies opening and closing and how this changes pharmacy access. Easy-to-view symbols flag whether each pharmacy would create or worsen a pharmacy shortage area if it closed.
"We thought carefully about who would use the tool - federal, state and local policymakers - to inform policies around pharmacies and created features they need," Vos said. "Users can use the time bar for states, counties and congressional districts."
"The tool is actively maintained, and there are a number of features and metrics we aim to release to the public as they become ready," Rozelle said.
The tool defines pharmacy shortage areas based on travel distance to the nearest pharmacy using scientifically derived distance thresholds:
- More than 10 miles in rural areas.
- More than 2 miles in suburban areas.
- More than 1 mile in urban areas.
- More than half a mile in low-income neighborhoods with low rates of vehicle ownership.
"Ultimately, our goal is to make pharmacy access visible and actionable, so that policymakers, health departments and advocates can identify where interventions are most needed and work to ensure that every community has access to the essential medicines people rely on," Qato said.
