A case unfolding in a Barrie courtroom brings home just what mischief can arise from bad, vague criminal laws poorly interpreted by ill-informed police and overzealous prosecutors in a climate of misinformation about HIV.

It also highlights why Ontario Attorney-General John Gerretsen needs to work with scientific experts, community organizations and people living with HIV to prevent unjust convictions and avoid further undermining HIV prevention and treatment efforts — neither of which outcomes are in the public interest.

After months in detention, a woman living with HIV is being tried for allegedly having sex with three men without disclosing that she has HIV.

The allegations have yet to be proved in court and every person is presumed innocent until proven guilty. But even assuming that the claims underlying the charges laid are proven in their entirety, several things are worth noting.

There is no allegation that she was maliciously trying to transmit HIV.

All of the “victims” were casual acquaintances — adult men who were willing, active participants in initiating the hookups.

The encounters were brief — a matter of a minute in one instance.

None of the men contracted HIV. This is not surprising, given the tiny risk of infection based on the alleged facts.

And get this: one of the counts against the accused woman rests solely on an allegation that she received oral sex “for a short period” — an act that poses extremely low risk, indeed close to zero risk, of transmitting HIV.

Most scientific studies have failed to identify cases of transmission through oral sex, although it’s difficult to find study subjects who have exclusively oral sex. Researchers now say the risk of transmission is so low it’s difficult to quantify. Practicing oral sex is a safer sex technique.

Yet this woman sits in jail facing the possibility of conviction for aggravated sexual assault, one of the most serious offences in the Criminal Code. If convicted, she faces possibly years in prison and a mandatory lifetime designation as sex offender.

How did we get to this sorry state of affairs?

Last fall, the Supreme Court of Canada released a pair of decisions that were criticized by HIV groups for authorizing an unjustly wide scope for criminal prosecution — at odds with the evolving scientific evidence about HIV, with most of the lower court decisions to date, and even with the direction previously suggested by the Supreme Court itself.

For instance, a person living with HIV can now be criminally prosecuted and sent to jail even if she or he took highly effective precautions to protect their partner by using a condom, had no intention to harm anyone and did not transmit HIV.

The decisions of the Supreme Court were also criticized for leaving unanswered questions about which sexual act might trigger prosecutions, including possible prosecution for oral sex. This leaves the door wide open for ignorance and prejudice to drive criminal prosecutions, as sadly illustrated by the case in Barrie.

In this case, we also have an additional factor: the accused woman had an undetectable “viral load,” which refers to the amount of the virus in a person’s bodily fluids. Science has conclusively established that the fewer copies of the virus, the less chance of transmission. When a person is under treatment and has an undetectable viral load, the risk of transmission through unprotected vaginal sex approaches zero.

So, on the one hand we have a risk that ranges from zero to extremely small, and on the other hand we have a woman facing conviction for aggravated sexual assault.

It’s out of all proportion and profoundly unjust.

Criminal prosecutions should be driven by reason, by evidence and by what’s in the public interest — not by irrational fear and prejudice that leads to people with HIV, even those who practise safer sex, being treated the same as violent rapists.

There is a better way than testing the limits of the law on the backs of people living with HIV through lengthy criminal proceedings, including months of pretrial detention and sensationalized and stigmatizing media coverage.

Police forces need to receive adequate training about HIV. This could help some of these charges from being laid in the first place.

And as the experience in other jurisdictions has shown, guidelines for Crown prosecutors can help prevent the misuse of the criminal law if developed in accordance with the current scientific understanding of HIV and international recommendations. Ontario’s attorney general needs to develop such guidelines, but with the meaningful participation of community organizations and scientific experts.