A scatter plot shows the relationship between varicella vaccination rates and cases per capita across five South American countries in 2020, with point size encoding population. The visualization uses D3 scales (`scaleLinear`, `scaleSqrt`, `scaleOrdinal`) and axes (`axisBottom`, `axisLeft`) to render the chart. A legend with hover interactions highlights individual countries by fading non-hovered points. The code loads embedded data rather than an external source and applies a custom theme with color assignments per country.