evidence: It has been two years since the first COVID-19 vaccine was given to a patient in the United States. Since then, the U.S. has administered more than 655 million doses — 80 percent of the population has received at least one dose — with the cumulative effect of preventing more than 18 million additional hospitalizations and more than 3 million additional deaths. The swift development of the vaccine, emergency authorization to distribute widely, and rapid rollout have been instrumental in curbing hospitalization and death, while mitigating socioeconomic repercussions of the pandemic. [...] From December 2020 through November 2022, we estimate that the COVID-19 vaccination program in the U.S. prevented more than 18.5 million additional hospitalizations and 3.2 million additional deaths. Without vaccination, there would have been nearly 120 million more COVID-19 infections. The vaccination program also saved the U.S. $1.15 trillion (Credible Interval: $1.10 trillion–$1.19 trillion) (data not shown) in medical costs that would otherwise have been incurred. [...] Vaccination also has prevented many millions of COVID infections. Although the acute phase of these infections may not have required medical attention, each infection carries a risk of long COVID and debilitating symptoms. Many of the prevented infections would have been reinfections, which have higher risk of death compared to initial infections. In addition, as our previous analysis demonstrated, vaccines have kept children in school, highlighting the societal value of the ongoing vaccination program.