Vito Russo is not a household name. He’s not even well known in the gay community, though he should be. The gay activist, who died in 1990 of AIDS, was extremely influential in getting mainstream media to change its approach to covering LGBT issues.

“Vito,” a new documentary for HBO, aired for the first time late last month. HBO is still showing it, and it’s definitely worth watching.

Perhaps best known for his 1981 book, “The Celluloid Closet,” Russo spent five years researching movies from the silent era to the contemporary, and what he uncovered was revelatory.

Russo found that gay characters were seen in movies as far back as silent films, and they were presented in generally positive terms. But in the 1930’s, as the government began enforcing a strict code of what Hollywood filmmakers could show, the subject of homosexuality was severely censored. And gay characters began a slow metamorphosis into comical sissies, misfits, and psychopaths. Film, being the powerful medium that it was for decades, left many Americans with the impression that gays were to be feared or pitied.

Even more troubling, Russo’s work revealed how many in the LGBT community had learned to view themselves with the same biases.

But Russo’s work didn’t stop with the publication of “The Celluloid Closet.” After the death of his boyfriend from AIDS, Russo co-founded ACT Up in response to the federal government’s slow reaction to the disease.

ACT Up approached protests differently than the sponsors of the peaceful marches and rallies of the past. Activists began targeting specific individuals and companies with their protests, bringing them unwanted media exposure.

ACT Up was credited with getting drug companies to lower their prices for the few drugs available to treat AIDS at the time. And it spurred the federal government to intensify research and hasten FDA approval of some drugs.

Russo was only in his mid-40’s when he died, but in a relatively short time he destroyed long-held beliefs about gay people. And he changed the LGBT community forever.