The film that started it all. To a greater or lesser extent, every zombie movie worthy of the name, Train to Busan, Juan of the Dead, Dead Set, Fido, all of them are unlicensed sequels or remakes of this one film. A copyright administrative error combined with a premise that can be realised on film with a suitable quantity of extras and a bucket of fake blood have made this film Patient Zero in the global pandemic of… oh yeah, sorry.
Of course, Night of the Living Dead itself stole its premise shamelessly from Richard Matheson’s I Am Legend. But while the vampires of I Am Legend were brought about through a bacterial strain (and one of the great joys of this book is watching Matheson expertly weave every strand of the vampire myth into a full-on hard science explanation of this bacteria’s symptoms), the ghouls of Night of the Living Dead are less easy to explain.
The best explanation we are given for the dead rising is radiation from a returning Venusian probe, and this isn’t contradicted anywhere in the film’s loosely organised sequels. In Romero’s zombie universe, you don’t become a zombie by “getting infected”. You do it by dying, and however you die, you’re going to get back up again.