Universal City, Calif. ? Two AIDS doctors made a house call last month to the set of TV’s “Law & Order: Special Victims Unit.”

The plot line was the suggestion that HIV doesn’t cause AIDS – a fringe theory promoted on the Internet and by certain African leaders. But the two physicians weren’t there to doctor the script.

They just wanted to make sure the TV show followed some standard doctor advice: First, do no harm.

Surveys show that most people believe the medical information they see on television dramas and soap operas. With fictional TV shows playing such a powerful role in public health education, the government is dedicated to keeping an eye on what Hollywood says. That’s why the Centers for Disease Control and Prevention is one of four government health agencies that fund the “Hollywood, Health & Society” program at the University of Southern California. The program has an annual budget of nearly $564,000.

It’s run by a former CDC employee, Vicki Beck, but the real “talent” are government health officials and other medical experts the program sets up with writers of daytime soap operas, nighttime dramas and other shows.

To be sure, many TV shows consult with doctors, lawyers and others professionals on plot details. Some even hire physicians to be writers. The executive producer of “Law & Order: SVU” is an MD.

Still, some TV and movie scripts skirt – or outright ignore – the practical limitations of the real world. Some low points:

¢ “Medical Investigation,” an NBC series in 2004-05, made health officials cringe. The show didn’t even get the names right: The series’ heroes did the out-in-the-field epidemic detective work of the CDC, but were identified as employees of the National Institutes of Health, a federal agency that’s more focused on lab science. Worse, the heroes wore leather jackets instead of protective gear when checking for a deadly pathogen.

¢ “Fatal Contact,” an ABC movie last spring about bird flu reaching the United States, was denounced as unrealistic by some prominent flu experts for, among other things, showing an Angolan village strewn with bloody bodies that looked more like a mass suicide than an area hit by flu.

¢ “Outbreak,” a 1995 motion picture starring Dustin Hoffman, involves a government plan to bomb a California town to stop the spread of an Ebola-like contagion. But CDC officials insist that they would not deal with such an outbreak by bombing towns.

Beck’s program tries to head off such errors.

The CBS show “Numb3rs” is one example. “Numb3rs” writer David Harden called, saying he was pursuing a plotline about black market profiteering in human organs. TV writers like the topic because of its dramatic potential and persistent hold on the public imagination: Who hasn’t heard the urban myth about the man who meets a woman in a bar and wakes up in a bathtub full of ice?

Health officials, however, hate it. They say there is no black market in organs in the U.S., and dramatizing the idea may dissuade Americans from becoming organ donors.

But the program took Harden’s call and convinced some experts to talk to him.

The resulting show, which aired in January 2006, was about an international black market that provided detailed information on how the national organ matching program works. Health officials deemed it a success: In a subsequent online survey of about 160 people who said they were not organ donors, 10 percent said they had decided to become donors after watching the episode.

CDC officials make time for Hollywood meetings because they know what’s on screen can be influential. In a 2000 CDC-sponsored survey, more than half of TV viewers said they trust health information on prime-time shows to be accurate, and about one-quarter said prime-time television is one of their top three sources of health information.

Health-focused plots, and sympathetic characters dealing with disease, do seem to stir public reaction. Just one example: A CDC study that chronicled the impact of a 2001 story line on a soap opera, “The Bold and The Beautiful,” in which a heterosexual male Hispanic character was diagnosed with HIV. The phone number to a CDC hot line for AIDS and sexually transmitted diseases was televised immediately after the episodes, and calls to the hot line spiked from about 100 a day to more than 1,400.

They do relatively little with movies. The CDC placed a smoking prevention employee in Hollywood in 2002 as a liaison with the motion picture industry, but stopped funding it in 2004. Beck hasn’t tried to fill that void.

“Film is too difficult to track and influence because of the many years, writers and stages of change that a film undergoes before it is released,” she said.