The apparent byproduct of watching too much Bad Boys II, The Viral Factor is a cops-and-criminals saga slathered in glossy Michael Bay-isms. Director Dante Lam's story involves a new super-strain of smallpox sought by Sean (Andy Tien), an evil government agent who, in an act of in-mission betrayal, murdered the partner and girlfriend of cohort Jon (Jay Chou) while leaving him with a bullet in his head that will spell death in just two weeks. Rather than sitting in a hospital waiting to die, Jon visits his mom (Elaine Jin), who suddenly informs him that he has a secret older brother, whom Jon soon meets—in one of those only-in-the-movies chance encounters—in the line of duty, since his sibling Yeung (Nicholas Tse) is a notorious wanted thief. Alongside their father (Liu Kai-chi) and Yeung's daughter Champ (Crystal Lee), the two come to an uneasy alliance in order to stop Sean (and his legion of cronies and corrupt cops) from developing the bio-weapon. That generic mission involves rescuing a beautiful doctor before Sean can force her to develop the virus as well as an antidote, which the villain then plans to use, Diabolical Plot 101-style, to sell back to the world at a billion-dollar profit for himself and his featureless European benefactors.
Though feigning Contagion-style concerns about the terrifying threat of genetically engineered plagues, The Viral Factor is a work of little more than repetitive shootouts and overwrought histrionics, the former devoid of excitement or originality, including two virtually identical sub-Heat gunfire-and-car-chase sequences set in crowded city streets, and the latter vainly attempting to lend some emotional heft to the car commercial-slick proceedings. Lurking beneath the film's flashy exterior is an undercurrent about the import of nuclear-family loyalty and stability, all courtesy of Jon's mother's abandonment of her husband and Yeung, but such notions are drowned out by director Lam's incessant explosions, firearm skirmishes, and slow-motion effects, replete with the clichéd-to-the-point-of-parody image of a bullet flying from a gun's chamber toward the screen. Such conventions define The Viral Factor, which for all its noise and motion cares only for stock tropes and devices—including, ultimately, a third act consumed with phony little-girl-in-peril suspense—that are in service of drama that, given every dilemma's obvious upbeat and/or faux-tragic outcome, is nothing more than a transparent put-on.