The plot synopsis of 28 Years Later reveals a major detail about how the world has changed since the previous installment. 2002’s 28 Days Later introduced the rage virus, a virulent disease that transforms its hosts into the ravenous, fast-moving, zombie-like Infected. While the outbreak in the movie was limited to the island of Great Britain, the finale of the 2007 sequel 28 Weeks Later featured it spreading to continental Europe by showcasing a group of Infected running through Paris after surviving characters Tammy (Imogen Poots) and Andy (Mackintosh Muggleton) crash-landed there.

https://screenrant.com/28-years-later-movie-story-what-happened-infected/