FILM REVIEW; Spared by a Virus But Not by Mankind

When ''28 Days Later'' is not scaring you silly, it invites you to reflect seriously on the fragility of modern civilization, which has been swept away by a gruesome and highly contagious virus while the hero lies peacefully in a coma. Four weeks after a laboratory full of rage-infected monkeys has been liberated by some tragically misguided animal rights militants, the whole of London -- and possibly every place else -- has been substantially depopulated. The churches and alleyways are littered with corpses, and fast-moving, red-eyed ''infecteds'' roam the streets looking for prey. Even the rats flee from them, and the few healthy humans face a Hobbesian battle for survival.

But what is most striking, and most chilling, about the early scenes of this post-apocalyptic horror show, directed by Danny Boyle and written by Alex Garland, is the eerie, echoing emptiness. Stumbling out of his hospital bed, Jim (Cillian Murphy), a former bike messenger, encounters a familiar metropolis that has been almost entirely stripped of life. Postcard images of the Thames, London Bridge and the dome of St. Paul's Cathedral take on a lurid, funereal glow. After centuries of bustle and enterprise, what remain are vacant buildings, overturned double-decker buses, looted vending machines and cheap souvenir replicas of Big Ben scattered across the sidewalk.

In their previous collaboration, ''The Beach,'' Mr. Boyle and Mr. Garland tried to imagine how a small group of people, removed from the modern world, might reconstitute society from scratch, an experiment whose failure seemed preordained for both the characters and the filmmakers. Here, working with a more solid premise, a smaller budget and greater freedom (and without big movie stars), they probe a similar theme more persuasively.

Jim, it turns out, is not entirely alone. Before long, he and some other survivors -- a prickly loner named Selena (Naomie Harris); an affable dad, Frank (Brendan Gleeson); and Frank's adolescent daughter, Hannah (Megan Burns) -- have formed a tiny band of nomads, traveling the English countryside in a big, black taxi and discovering that caring for one another is not just a residue of extinct social norms, but also an expression of the survival instinct.

Other expressions, as you might expect, are not so inspiring. Through the silence comes a radio signal, a voice promising that salvation and the answer to the virus lie with a group of soldiers just north of Manchester. They are led by Maj. Henry West (Christopher Eccleston), who seems to have graduated from a ''Lord of the Flies'' military academy. He and his men are on hand to demonstrate that those who offer protection and security can be even more dangerous than the virus-crazed zombies they keep at bay.

The soldiers also allow Mr. Garland and Mr. Boyle an exit from nightmarish claustrophobia into a more conventional (though still quite effective) action-and-suspense story. As such, and as a parable of human nature under extreme duress, ''28 Days Later'' is never less than interesting and acknowledges fairly directly its debt to the visionary ghoulishness of George Romero, who made ''Night of the Living Dead,'' ''Dawn of the Dead'' and ''Day of the Dead.'' The suggestive juxtaposition of zombification and consumerism in ''Dawn,'' which took place mostly in an abandoned shopping mall, is evoked in several scenes here, as are the queasy racial politics of ''Night.''