Some of the aerial footage was shot by a second unit in the ghost town of Pripyat, near Chernobyl, in Ukraine. Director Colm McCarthy: "I was very interested in post-apocalyptic imagery and urban exploration. We wanted to surprise people rather than have people coming in expecting a studio level film. We sent a micro drone unit to Pripyat, Chernobyl to shoot helicopter footage with Pripyat doubling for urban London." [2016]
Glenn Close's sister-in-law, Deb Close, is a massive fan of zombie films, having always wanted to be in one, and has a small role as one of the "hungries" in the scene where the group has to work their way through a crowd of them. She is the one wearing a blue knit, with green facial fungus and blood around the mouth and neck, that Glenn stares at as her character walks past. Deb flew to the UK especially for the part, and the first thing Glenn did after accepting her role was call to let Deb know she was in a zombie film.
The film shares similar themes and plot points to the PS4 video game the Last of Us. Both feature a fungal zombie plague, both have a last stage of infection where people sprout spore pods, both zombies overwhelming rely on a single sense (smell and sound respectively) meaning the heroes can move from hordes, both feature a young girl who potentially has the cure who needs to be moved through the infected zone, both focus on her relationship with a gruff reluctant father figure. The similarities were highlighted in several reviews.
Some of the scenes were shot in the middle of the busy Birmingham (UK) business district.
According to director Colm McCarthy an influence on the style was Gareth Edwards's Monstros (2010): "I also spoke to Gareth Edwards about "Monsters" ahead of shoot. That film was a reference point." [2016]
Mike Carey: Writer of the book and film briefly appears as one of the "hungries" thrashing against the fence to the military base, wearing a jacket and blue shirt at the front.