The implications of Mabior for people living with HIV

Posted By Rosel Kim – Oct. 13, 2012

On October 5, 2012, the Supreme Court issued a ruling on two cases on HIV status non-disclosure to sexual partners. R. v. Mabior and R. v. D.C. provided an opportunity for the Court to clarify its position on HIV status non-disclosure to sexual partners.

 Part I: What the Court said


Clato Mabior was diagnosed with HIV in 2004 and began antiretroviral therapy shortly afterwards. He had an undetectable viral load (where the HIV virus was fully suppressed in the body) from October 2004 to December 2005.  Between January 2004 and March 2006, he had sexual intercourse with multiple women with intermittent condom use, without disclosing his status. No transmission of HIV occurred. At trial, Mabior was convicted of six counts of aggravated sexual assault.

When D.C. first met her ex-partner in 2000, she had an undetectable viral load.  She did not disclose her HIV status when they first slept together. D.C. stated a condom was used, but her ex-partner later testified that no condom was used. She disclosed her status afterwards, and they were in a four-year-long relationship. Their relationship was abusive, and ended with D.C. calling the police after being physically assaulted by her ex-partner. He was charged with assault in November 2004. In February 2005, D.C.’s ex-partner complained to the police that D.C. did not disclose her HIV status after their first sexual encounter. As a result, she was charged with aggravated sexual assault and sexual assault. D.C.’s partner never contracted HIV.

 Existing law on HIV status non-disclosure

Until Mabior, the criminal law imposed a duty to disclose one’s HIV status to sexual partners if there was a “significant risk of bodily harm” (R v. Cuerrier, 1998). Failure to disclose would lead to a charge of sexual assault or aggravated sexual assault, because the court stated that the partner’s consent to have sexual relations was vitiated by the non-disclosure.

The Court declined to define the meaning or scope of “significant risk,” though it did suggest that proper condom use may alleviate significant risk in obiter. Cuerrier resulted in varied interpretations and applications of the law by lower courts.

Risk of HIV transmission by the numbers

 For unprotected vaginal intercourse, the risk of HIV transmission is assessed to be about 0.08-0.1%.  If a person has an undetectable viral load, the risk is reduced to about 0.01%. (E. Mykhalovsky, HIV Non-Disclosure and the Criminal Law: Establishing Policy Options for Ontario, 2010, available online at

When a condom is used properly, the risk of transmission can go down to virtually zero. Generally, consistent condom use is said to reduce the risk of transmission by 80 per cent.

The Court’s ruling in Mabior (

The issue at the Supreme Court was whether the Cuerrier test was still valid.

After reviewing other common law jurisdictions that criminalize non-disclosure when there is HIV transmission (such as the UK, some Australian jurisdictions and New Zealand), the Supreme Court rejected this approach for being too burdensome on the Crown.

The Court also rejected a “reasonable partner” approach (which stated that every person is responsible for his/her own sexual health, rather than putting the burden on the person living with HIV). The Court ruled this approach would not be suitable because the passionate nature of sexual relations would impede assessment of what a reasonable partner would expect.

Instead, the Court decided to define the scope of “significant risk” and uphold the Cuerrier test. Stating that a 1 in 10,000 chance of contracting HIV through vaginal sex if a partner has an undetectable viral load is a “realistic possibility,” the Court ruled that significant risk is only negated if a person’s viral load is low (below 1,500 copies/ml) and if a condom is used.

The Court’s ruling in D.C. (

 The Court applied the Mabior test in D.C., but acquitted D.C. on the ground that her ex-partner was not a credible witness, and the Crown failed to establish beyond reasonable doubt that there was no condom use in their encounter.


NOTE: Pt. 2 of this blog post will discuss the HIV community’s reaction and worrisome implications arising from the Supreme Court’s ruling. 

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s