A 2018 directive from Canada's former justice minister has led Crown attorneys to drop a sexual assault charge against a man who is HIV-positive.

Bobby Kaotalok was charged with sexual assault in Yellowknife after allegedly not disclosing his HIV-positive status to a sex partner. But in Northwest Territories Territorial Court on Tuesday, prosecutors announced they wouldn't go ahead with the case.

"We followed the directive and chose not to prosecute," said Crown attorney Alex Godfrey.

It's illegal for an HIV-positive person to have sex with someone and not disclose their status, if the incident poses a realistic possibility of transmitting the virus.

What constitutes a "realistic possibility" in Canadian law changed on Dec. 8, when former justice minister Jody Wilson-Raybould issued new guidelines in light of recent science.

Among other things, it encourages prosecutors to "generally" avoid pursuing charges if people are taking their drug treatment as prescribed.

Scientific evidence shows people who take their medications regularly may be able to keep traces of the virus so low in their blood that it becomes undetectable, and people with these extremely low viral loads don't have a realistic possibility of transmitting the virus to others.

Jay Bran, Kaotalok's attorney, said the Crown decided not to continue with charges against his client after "medical documents gave us more insight into his medical condition."

Bran said he believes the Crown's decision not to prosecute Kaotalok "speaks volumes" about the level of risk — or lack thereof — to which he exposed the person he slept with.

The directive also encourages Crown attorneys to consider whether it's in the public interest to prosecute.

In 2013, Kaotalok, who's originally from Cambridge Bay, Nunavut, was sentenced for aggravated sexual assault after having sex with two women and not telling them about his status. He used a condom with one of the women. Under the new guidelines, sexual activity with a condom does not pose a realistic risk of transmission. As of 2013, neither woman had been diagnosed with HIV.

"I'm happy for my client," said Bran. "I know this was weighing very heavily on him … Today he's relieved and happy this prosecution is over."