It's not a question of trying vs. not trying, but possible vs. impossible. They know how time travel works (in this movie), and nothing can be changed. The pandemic is going to happen no matter what, because it already happened. Whatever they did in the past already happened also, and didn't make any difference.
What they did in the movie is beside the point. A series would be a different take on the concept, a different continuity, and thus free to reinvent the concept in whatever way suits the series' needs. Just like virtually every TV adaptation of a movie ever made.