The Canadian criminal law obligation requires individuals who are HIV-positive to disclose their status to every sexual partner before partaking in an activity that poses 'significant risk' of HIV transmission.

So how is significant risk defined...
Well, at the moment, the concept is quite blurry. 

In Canada, as well as many other countries, people living with HIV/AIDS (PLWHA) are being charged with criminal offences for activities that, according to science, should be classified as low risk. For many PLWHA who are undergoing treatment, their risk of transmission when engaging in sexual activity is reduced to almost 0%.

A York University study, published in the Social Science & Medicine journal, was the first of its kind to examine the consequences of criminalising HIV non-disclosure for Canadian public health. The author, Eric Mykhalovsky, a sociology professor in the Faculty of Liberal Arts and Professional Studies identified the need for the "parameters of significant risk to match what current science shows and what public health professionals understand."

Mykhalovsky discovered that the undefined concept of 'significant risk' has led to uncertainty amongst PLWHA regarding their legal responsibility to disclose. Not to mention the psychological stress around whether to disclose or not to disclose.

Ensuring that the legal system matches current definitions of 'significant risk' in HIV science will be most beneficial in increasing necessary disclosure and protecting the rights of PLWHA who have changed their behaviour in order not to disclose.