Chance Claybourne, in the fourth book Exposure, infects himself with XPB-19. His eyes glow red instead of gold when flaring.
It is believed that Chance has infected other people with this new infection.
When Tory was attacked on her way home in book 4, she witnessed three people with glowing red eyes. I believe this is a new pack, called the Infected, instead of Virals.
Chance's experiment, called "Brimstone", is designed to spread the powers to more people. Therefore, it is perfectly logical that he took the first step and infected himself as well as 2 others.
We still have yet to learn. Please put your comments below.