Antigenic Drift & Shift Simulator (2D Map)

A 2D model of how influenza-like viruses evolve around the immune system, plotted on an antigenic map you can pan and zoom by hand. A viral population starts clustered on the vaccine strain at the centre of the map, inside a dashed circle marking the reach of neutralizing antibodies. Advance generations to watch point mutations (antigenic drift) push surviving virions outward under immune selection pressure, or trigger a reassortment event (antigenic shift) to see a subset jump straight to a new subtype outside the antibody boundary — with live readouts for generation count, mean antigenic distance, immune-escape fraction and population size, plus a running history chart of how those last two evolve over time.