TV audiences have seen all sorts of amazing and horrifying things on AMC's "The Walking Dead" and its companion series "Fear The Walking Dead." However, one thing they have not seen is answers. Where did the zombie virus originate? How did it spread? Does a cure exist? These are questions that both shows have zero interest in answering, though it hasn't stopped fans from theorizing about it.

Apparently, it hasn't stopped the actors either. "Fear The Walking Dead" star Cliff Curtis recently discussed with Collider how he thinks the zombie apocalypse may have started.

"It's not on the show, but what I think is a really strong possibility is that all of the government laws around immunization of children and how it's illegal to not be immunized, so that you have all of these kids who, for generations, are immunized, but then something goes wrong and you have thousands and thousands and thousands of people, all around the world, buying these immunizations for flu shots or to fight bacteria or disease, and we've basically become over-immune and our immune system takes over and refuses to let the body die. That's my theory."

Remember, this is just Curtis' own thoughts on the matter. He hasn't received any inside information from creator Robert Kirkman or anything. But his theory is interesting to think about. Although, if true, humans would be dealing with other more worldly diseases in addition to zombies, it's as good as an explanation as we've gotten over the last several years.

"The Walking Dead" and "Fear The Walking Dead" have no intention on answering that central question, so it's good to discuss any and all theories that come about. Curtis himself shares the frustration of viewers who want a bit more background information.

"I'm not okay with that. I want to know how all of this happened. I'm like, 'Come on, guys! Give me the information!'

Initially, "Fear" showrunner Dave Erickson wanted to offer up a concrete explanation for the zombie virus but was vetoed by Kirkman. Now, the time for answers has passed which means viewers will have to continue coming up with their own reasoning's.

"Fear The Walking Dead" will return in spring or summer of 2016. "The Walking Dead" will return on Feb. 14.