Medical - Health Promotion and Protection Act (HPPA). R. v. Aziga
In R. v. Aziga (Ont CA, 2023) the Court of Appeal, in the course of a murder appeal, reviewed some HPPA activities respecting communicable diseases:
 In June 2002, one of these 9 complainants, S.B. learned that she was HIV-positive, and later listed Mr. Aziga as a sexual contact. Given ongoing concerns Hamilton Public Health had about his failure to respond to the warnings and counselling he had received, Mr. Aziga was notified on October 17, 2002, that he was being ordered pursuant to s. 22 of the Health Protection and Promotion Act, R.S.O. 1990, c. H.7 (the “HPPA”) to attend additional counselling and educational sessions, to refrain from unprotected sex without first advising his partner, and to provide a full list of his sexual partners since his HIV diagnosis.. Ontario Nurses’ Assn. v. Chief Medical Officer of Health (Ontario)
 Although Mr. Aziga attended further counselling and education sessions as ordered, he repeatedly breached the order. Again, it was not contested at trial that he subsequently continued to engage in multiple unprotected sexual acts with H.M. and B.H. (Counts 7 and 12), without disclosure, and he engaged in one unprotected sexual act without disclosure with a new partner, J.C. (Count 8). He also began a sexual relationship with a new girlfriend, H.B. (Count 5) without disclosing his HIV status. The evidence established that he failed to provide a full list of his sexual partners to public health officials, and he continued to refuse ART.
 In early 2003, L.C. (Count 13), who had become HIV-positive, also listed Mr. Aziga as a sexual contact. Public health officials implored him to comply with the s. 22 order. He told them he understood the law but did not agree with it. On August 21, 2003, he was served with a Superior Court of Justice order made pursuant to s. 102 of the HPPA, containing the same basic conditions as the s. 22 HPPA order.
In Ontario Nurses’ Assn. v. Chief Medical Officer of Health (Ontario) (Div Ct, 2021) the Divisional Court considered the 'precautionary principle' in the HPPA:
The Precautionary Principle
 The precautionary principle referred to in section (2) above was perhaps most famously articulated by Justice Archie Campbell in the Report of the SARS Commission, entitled Spring of Fear (Volume 1, December 2006) (“SARS Commission Report”). In his report, Justice Campbell highlighted the important distinction between infection control and worker safety in the face of a novel coronavirus. He pointed out that while infection control measures must rely on evolving science, worker safety cannot. He wrote, at p. 12:
When it comes to worker safety in hospitals, we should not be driven by the scientific dogma of yesterday or even the scientific dogma of today. We should be driven by the precautionary principle that reasonable steps to reduce risk should not await scientific certainty. The HPPA was amended following the release of the SARS Commission Report to require that the CMOH consider the precautionary principle when issuing directives relating to the health and safety of health care workers in Ontario. ....