Why the “last mile problem” is keeping vaccines out of arms.

“Access” isn’t just about having enough vaccines. It’s about getting them where they need to go.

When I served as the city of Detroit’s Health Director five years ago, our city routinely had the lowest vaccination rates in the state. Part of that was due to skepticism about vaccines, dubbed, in 2021 parlance, “vaccine hesitancy” (I’ll talk about why that term is surprisingly unhelpful in a future post). 

Detroit is 85% Black. And distrust of biomedicine isn’t just a function of the biomedical establishment’s history of exploiting Black folks but the lived experiences of being actively discriminated against in clinics and hospitals today. Black babies die at two times the rate of their white counterparts—their mothers die at threefold the rates. This isn’t history, this is now. 

But distrust wasn’t the only problem. Detroit’s low vaccination rate also reflects a challenge of inaccessibility. When we talk about vaccine inaccessibility, we’re primed by recent events to conjure up images of long lines at drug stores. The lack of supply has been the bottleneck in COVID-19 vaccines for the first four months of 2021 after all. But as my experience in Detroit half a decade ago demonstrates, inaccessibility has been an issue with vaccines since well before COVID-19. It’s not that we lacked supply of vaccines for polio or measles, mumps, and rubella. It’s that too few Detroiters could get to them. Vaccine access is a classic “last mile problem.”

Last mile problems are familiar to anyone who’s thought about the logistics of delivery of people, services, or goods from one place to another. Indeed, it accounts for upwards of 53% of their shipping costs, meaning FedEx, UPS, the US Postal Service—all of them are constantly thinking about it. Last mile problems also flummox efforts to build reliable public transportation. It’s easy to connect Detroit to Chicago by train—but what’s the transit solution between the train station at either end...and your house? Last mile problems arise when the final stage of delivery introduces vastly more complexity because the last mile is impossible to scale: Many people need to go from Chicago to Detroit. Only you (and your housemates) need to go from the train station to your house. But because everyone has a different final destination, the “last mile” poses a challenge at scale, without a scalable solution. 

In Detroit, and cities like it, structural racism compounds poverty to rob residents of functional infrastructure—good schools, good jobs, clean air, quality housing, even street lights (For years the Detroit’s city lights just didn’t work!). Even before the pandemic, getting your child vaccinated wasn’t as simple as going to your local pediatrician’s office. For starters, most of Detroit’s vast 138 square miles is a healthcare desert. Too often, primary care physicians don’t set up clinics in Detroit neighborhoods. Getting in your car and driving to the nearest pediatric clinic isn’t so simple either—the nation’s highest auto insurance rates force residents of the Motor City to choose between owning a car and driving it legally. Taking public transit poses its own set of last mile problems in a city without a major light rail system. It may mean waiting up to an hour for a bus after walking an hour there. Changing buses could mean another hour in wait time. And how do you get to the actual clinic from the bus stop in suburbs built around car access? All of that conspired to make getting a child vaccinated a challenge for Detroiters even before the pandemic.

Enter the rush to vaccinate Americans against COVID-19. In high- and middle-income communities, solving the last mile for vaccinations is rather easy. We rely on people to leverage their own resources to solve it for us. If you can build a massive vaccination site, people just pop online, make an appointment, and drive on over. If the only available appointment is during the workday? That’s fine—their supervisor will be eager to give them time to get vaccinated. After all, the faster the office is vaccinated, the faster the office...gets back to the office.

But Detroiters can’t rely on their own resources to solve the last mile problem for themselves because resources are so limited. Popping online to make an appointment? Broadband access in Detroit is spotty. One study by the University of Michigan estimated that 70% of Detroit school children lack broadband access. Getting downtown has the same challenges as getting...anywhere for too many Detroit residents. And taking time off work? That’s harder to do when you work an hourly-wage job with erratic just-in-time scheduling and time off means less pay. The city did set up one of Michigan’s biggest mass vaccination sites—downtown at Ford Field, home to the Detroit Lions. But it’s catered more to suburbanites than local Detroiters.

If we’re serious about maximizing vaccinations in communities like Detroit all over the country, then we’ll have to be serious about solving the last mile problem. And that means taking vaccines to the people who need them. Not just to their cities, or their neighborhoods—but right to them. It means centering the folks we’re trying to serve by thinking through the most opportune times to take vaccines to their doorsteps. 

Such a door-to-door approach is being piloted to notify residents that they can go to a local neighborhood vaccine clinic. But what’s missing? Thevaccines. Won’t that be a huge logistical lift? Yes, absolutely. But so is the goal of vaccinating every American against COVID-19 in the first place. To accomplish it, we have to stop assuming that every American has the same set of resources, and start solving the last mile problem for those who don’t.