Chelsea, Massachusetts, had one of the highest COVID-19 transmission rates in New England in the summer of 2020. The Chelsea Project was a collaborative effort in which government entities, local nonprofit organizations, and startups partnered to deploy wastewater analysis, targeted polymerase chain reaction testing and vaccine outreach, and a community-led communications strategy. The strategy helped increase both testing rates and vaccination rates in Chelsea. Today Chelsea has one of the highest vaccination rates among US cities with comparable demographics. (Am J Public Health. 2023;113(6):627-630. https://doi.org/10.2105/AJPH.2023.307253).