HIV can only be transmitted in specific circumstances. Contrary to many people’s ideas, HIV is not particularly easy to transmit. This section contains scientific evidence about the risk of HIV transmission.
Provides current scientific evidence to facilitate just outcomes in Australian criminal cases involving HIV. Argues that careful attention should be paid to the best scientific evidence on HIV risk and harms, with consideration of alternatives to prosecution, including public health management. Authored by leading Australian HIV clinicians and scientists.
Sets out in clear, concise, and understandable terms a collective expert opinion about HIV sexual transmission, transmission associated with biting and spitting, and HIV as a chronic manageable condition. Authored by six distinguished Canadian HIV clinicians and scientists.
This document from the Center for HIV Law and Policy, published in 2011, lists articles on a range of background issues relevant to HIV criminalisation (particularly in the U.S.) including HIV as a chronic condition, coverage under the ADAAA, transmission routes and risk, viral load and treatment, and phylogenetic analysis.
Reports findings from systematic review and meta-analysis of the literature on HIV-1 infectiousness through anal intercourse.
Reports findings from systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact (43 publications based on 25 studies).
Reports data from a prospective study of African HIV-1–serodiscordant couples assessing transmissions for linkage within the study partnership, based on HIV-1 sequencing. Modifiable risk factors were (HIV-positive partner) RNA level and condom use, and (HIV-negative partner) presence of STIs and male circumcision.
Reports data from a longitudinal cohort study of community-based HIV-negative homosexual men in Sydney, Australia. Reports risk of infection through unprotected anal intercourse.
Reports analysis of recent studies on per-act HIV transmission risk and modifying factors. Includes risk associated with blood transfusion, vertical exposure, sexual exposures, and parenteral exposures. Finds the risk of HIV acquisition varied widely, with risk from sexual transmission substantially reduced by combined use of condoms and antiretroviral treatment of HIV-infected partners.
Reports on follow up from prospective cohort study of gay and bisexual men. Findings include estimates of risk from unprotected anal intercourse and oral sex.
Explains HIV transmission risk with reference to numerous studies, including a chart summarising per-act risk estimates for transmission of HIV during different types of sexual intercourse.
(update of original chapter in E. Mykhalovskiy, G. Betteridge and D. McLay, HIV Non-Disclosure and the Criminal Law: Establishing Policy Options for Ontario)
This factsheet from the Center for HIV & Law Policy, published in 2017, outlines HIV transmission risk (based on “HIV Medicine and Science: Transmission Considerations”).
Review of 14 rigorous studies to re-estimate condom effectiveness in reducing heterosexual transmission of HIV. Finds consistent condoms use results in an 80% reduction in HIV incidence, i.e 80% less than the particular act without condoms. Consistent use is defined as using a condom for all acts of penetrative vaginal intercourse.
Recent meta-analyses of condom effectiveness suggest that condoms are 60 to 70% effective when used for HIV prophylaxis. A re-examination of HIV seroconversion studies suggests that condoms are 90 to 95% effective when used consistently, i.e. consistent condom users are 10 to 20 times less likely to become infected when exposed to the virus than are inconsistent or non-users. Similar results are obtained utilizing model-based estimation techniques, which indicate that condoms decrease the per-contact probability of male-to-female transmission of HIV by about 95%.
Systemic review of medical literature found male circumcision is an effective strategy for reducing new male HIV infections, however, its impact at population level requires consistently safe sexual practices to maintain the protective benefit.
Reviews evidence related to the potential for HIV transmission through human bites. Concludes that while biologically possible, transmission remains unlikely, risk is epidemiologically insignificant and as yet, has not been well documented.
This 2013 factsheet produced by the Center for HIV Law and Policy, the National Organization of Black Law Enforcement Executives and the Association of Prosecuting Attorneys provides current factual information about the HIV transmission risks law enforcement professionals may face in the line of duty (aiming to address the frequent overstating of risk). States there is no known case of a law enforcement officer being infected in the line of duty through spitting or biting.
Report of small study following an HIV-positive man with severe brain damage and poor dental hygiene (causing bleeding gums) who was frequently violent to hospital staff. After 2.5 years follow up, all of the 30 people he’d bitten or scratched remained HIV-negative.
Compares risk of HIV transmission from a single sexual encounter with odds of illness or death from other life events.
A systematic literature search was conducted using Medline, Embase and Northern Lights databases and conference websites. Results showed that there was no risk of transmitting HIV through spitting, and the risk through biting was negligible. Post‐exposure prophylaxis was not indicated after a bite in all but exceptional circumstances. Policies to protect emergency workers should be developed with this evidence in mind.
While some policymakers and courts have recognized condom use as sufficient to negate possibility of HIV transmission, people living with HIV in Canada remain at risk of prosecution for alleged non-disclosure before sex with a condom. While the law may be unsettled, the science and policy reasons are clear: prosecuting people living with HIV who use condoms is unscientific and unfair. Law- and policymakers must act to definitively preclude prosecutions against people living with HIV who use condoms.
Twenty scientists from regions across the world developed this Expert Consensus Statement to address the use of HIV science by the criminal justice system. Description of the possibility of HIV transmission was limited to acts most often at issue in criminal cases. The authors recommend that caution be exercised when considering prosecution, and encourage governments and those working in legal and judicial systems to pay close attention to the significant advances in HIV science that have occurred over the last three decades to ensure current scientific knowledge informs application of the law in cases related to HIV.
In 2018, twenty leading HIV scientists published the ‘Expert Consensus Statement on the Science of HIV in the Context of Criminal Law’ (Expert Consensus Statement) to address the misuse of HIV science in punitive laws and prosecutions against people living with HIV for acts related to sexual activity, biting or spitting. The process involved undertaking detailed analysis of the best available scientific and medical research data on HIV transmission, treatment effectiveness and forensics. Building on an initial scoping report published in 2020, the HIV Justice Network (HJN) undertook further research between April and July 2023 examining the impact of the Expert Consensus Statement in cases and advocacy in the five years since its publication.
