28 Years Later is an upcoming post-apocalyptic horror film directed by Danny Boyle, from a screenplay he co-wrote with Alex Garland. Produced by Columbia Pictures in association with BFI, DNA Films and Decibel Films, it serves as a sequel to both 28 Days Later (2002) and 28 Weeks Later (2007). It stars Cillian Murphy reprising his role from 28 Days Later, alongside Aaron Taylor-Johnson, Jodie Comer, Ralph Fiennes, and Jack O'Connell.
TBH after the initial premise of zombies itself being unrealistic, I don't find the addition of a virus returning to be problematically unrealipstic.