Under the right circumstances, a virus can infect any computer.
The scientists say there is no evidence that the virus can infect people.
But the vaccine doesn't work against a virus already infecting the body.
The risk is generally low to most people, because the viruses do not usually infect humans.
Even very small breaks in the skin allow the virus to infect the body.
The behavior of children with animals may provide a clue to the possible ways the virus infects people.
One possibility is that the virus does not infect human cells directly.
During the intro, the game explains that a virus has infected the world's computer systems.
Such viruses, the researchers found, could no longer infect monkey cells.
A10 Researchers found a spring that helps viruses infect humans.