From an article:

In the book's opening chapter, Jeevan only encounters a young Kirsten backstage before they go their separate ways. He and Frank endure the 80 days in the apartment together until Frank, who is a paraplegic, commits suicide (in the series, an invader kills him with the knife that becomes Kirsten's weapon).

In the tv show, Jeevan and young Kirsten spend 80 days quarantining together


Big difference!