A major US porn movie maker is to resume filming next week, almost a month after the multibillion-dollar industry was virtually shut down after an actor tested HIV positive, it said.

Vivid Entertainment, one of the world’s biggest producers of porn films, said it was satisfied after exhaustive tests were carried out on all partners of the actor at the center of the scare.

“We made the decision to halt production as the health and well-being of our performers is of utmost importance to us,” said Vivid’s founder and co-chairman Steven Hirsch, announcing the resumption of filming from Monday.

“We can now confirm that all performers who were on the quarantine list as a result of being exposed to the HIV positive performer have gone through two rounds of testing and the results are negative.”

The alarm was sounded last month after an actor tested HIV positive at the Adult Industry Medical Healthcare Foundation (AIM), a clinic for workers in the porn industry, centered on the San Fernando Valley north of Los Angeles.

At least four major film producers suspended filming while tests were carried out on all the known partners of the actor, who was not identified although he was understood to be male.

The case, which fueled calls for film companies to force actors to use condoms, is the first in over a year in the industry, and comes six years after up to 14 actors tested HIV positive forcing several movie firms to close.

Vivid’s chief praised the role of the clinic which alerted the industry to the HIV positive test. “We believe that AIM acted professionally and thoroughly and proved that their system works,” said Hirsch.

“We will, of course, continue to require recent test results for all performers in our movies and will continue to take all necessary precautions to assure their health and safety.”