This example displays two time-series scatter plots tracking COVID-19 cases and vaccination rates across the US population, using data from the NY Times and Our World in Data. The upper plot shows rolling averages of cases or deaths, while the lower plot displays the percentage of people vaccinated, with an annotation highlighting the peak vaccination value. Built with D3.js, the visualization uses `scaleTime` and `scaleLinear` for axes, `d3.annotationLabel` for annotations, and animated transitions via `transition.duration`.