This scatter plot animates COVID-19 vaccination rates and 7-day average case counts for the US population, using a dual y-axis where steelblue circles represent the proportion of people vaccinated and gray circles represent case counts. The visualization demonstrates that as vaccination numbers rise, case numbers decline, with annotations highlighting the peak and final case counts. Built with D3.js (version 6.7.0), it implements reusable scatter plot patterns with custom scales for time and linear axes, animated circle growth, and interactive menu selection for toggling between partial and fully vaccinated data. The code leverages D3's data joins, transitions, and annotation APIs, pulling data from Our World in Data and the New York Times rolling averages dataset.