The global struggle against coronavirus disease 2019 (COVID-19) is now in its eighth month since the pandemic virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first emerged. The severe economic, personal, and psychological adverse effects of shutdowns and social distancing make these effective preventive measures challenging to sustain long-term. In 1999, just before the launch of a new millennium, the Centers for Disease Control and Prevention listed vaccines as the most important public health achievement of the 20th century.1 According to one estimate, more than 42 000 children’s lives are saved annually as a result of the US programs of routine childhood immunizations.2 Safe and effective COVID-19 vaccines could lead to a level of global immunity that stops the pandemic. This is the anti–COVID-19 intervention most public health leaders and many people long for the most.