By October 2022, almost two years after the first COVID-19 vaccines were rolled out, 80% of people in the [United States] aged six months and older had received at least one dose. However, only 33% had received a follow-up booster, which offers the highest possible level of protection against the SARS-CoV-2 virus.
The low booster numbers drove some states to investigate how uptake might be increased. Researchers and health authorities have highlighted ‘last-mile vaccination delivery’ as a major barrier to uptake. In 2021, the White House came up with the idea of encouraging people to get their boosters by offering them free transport to clinics through the ride-hailing companies Lyft and Uber. But a study published in Nature last month shows that this might have done little to increase booster uptake.
Economist Katherine Milkman at the University of Pennsylvania (UPenn) in Philadelphia and her colleagues compared the offer of a free ride with other interventions in a study involving 3.66 million patients of CVS Pharmacy, a retailer that provides vaccination services. The patients, who had all previously been vaccinated against COVID-19, were split into eight groups. One group received a text message offering free transport to the pharmacy; the other seven were sent different text-message reminders to get their boosters.
“Our article really highlights the importance of testing policy,” says study co-author Sean Ellis, also at UPenn. “Whatever policy we’re putting into place, we should be robustly evaluating whether it actually works, so that if it does work, we can scale it up or continue to do it. And if it doesn’t, we can move on from it and try something else.” In other words, studies are needed to evaluate whether ‘common sense’ interventions actually work in practice.