Everyone Wins: Vaccine Lotteries Can Cost-Effectively Increase COVID-19 Booster Vaccination Rates

Booster vaccination remains a key strategy to address the ongoing threat of coronavirus disease 2019 (COVID-19). However, take-up has been slow. By the fall of 2022, less than 50% of eligible US residents had received a booster dose. It is a central tenet in health economics that incentives or penalties are necessary to reach optimal vaccination rates. Six rigorous real-world studies provide evidence that COVID-19 vaccine lotteries cost-effectively raised vaccination rates at an estimated cost of $49 to $82 per additional dose. The 5 studies that found no impact of lotteries used statistical methods that underestimated the impact: They were statistically underpowered to detect a small yet cost-effective impact and did not adequately address selection bias. Vaccine lotteries are cost-effective because they not only provide financial incentives but also influence the public via nonfinancial channels: They garner media attention, tap into social networks, combat procrastination, and signal the importance of sustaining high vaccination rates. In fact, vaccine lotteries are likely to be more effective for booster vaccination than for initial doses because barriers to vaccination are higher. The ongoing threat of COVID-19 presents a unique opportunity to develop and implement innovative, evidence-based public health policies like vaccine lotteries to address current challenges.