Frequently asked questions regarding criminal liability for HIV transmission

Published: 20 August 2013
  • The information below clarifies key issues for healthcare professionals and people living with HIV regarding disclosure of HIV status, the use of condoms, the meaning of ‘recklessness’, police investigations, confidentiality, and the use of evidence in criminal cases.

Must an HIV-positive individual disclose their HIV-positive status before having sex?

There is no law that requires disclosure before sex (whether protected or unprotected) in any part of the UK. However, should someone be prosecuted for 'reckless' HIV transmission in England, Wales or Northern Ireland, it is a defence to argue that the complainant knew that the accused was HIV positive and had, therefore, consented to the risk of transmission (known as 'informed consent'). This is a not defence in Scotland, however.

Although direct disclosure is the most obvious method to ensure that the other person is specifically aware of, and consents to, the risk of infection, the CPS acknowledges that there may be other ways in which the person making the complaint had been ‘informed’ of the accused’s HIV status. The examples they give include:

  • A third party had previously informed them of the accused's HIV-positive status.

  • The complainant has visited the accused in hospital while they were undergoing treatment for an HIV-related illness.
  • The accused is showing obvious symptoms of infection.

It is not clear, however, whether additional forms of non-direct disclosure would be admissible as a defence. Examples could include: posting one's HIV-positive status on an online-dating profile; leaving out antiretroviral medications for the non-informed partner to discover; or meeting at a public sex location where everyone is assumed to be HIV positive.

Whatever the method, proving that there was 'informed consent' to the risk of HIV transmission is difficult, and may often end up being one person’s word against another.

If a person with HIV is concerned about the possibility of a police investigation or prosecution, then the best way to avoid such possibilities would be to make sure that (all) their sexual partner(s) explicitly agree to have sex with them, knowing they are HIV positive.

Since it may be difficult to later prove in court that they disclosed their HIV-positive status, a group of Canadian non-governmental organisations has issued a guide1 that contains the following recommendations for gay men living with HIV:

  • Disclosing one’s HIV status to a potential sexual partner in front of friends who could act as witnesses.
  • Asking a third party to confirm that the potential sexual partner is aware of the HIV-positive diagnosis.
  • Saving online conversations and emails that confirm disclosure as well as the potential sexual partner’s confirmation that the information was received.
  • Disclosing one’s HIV-positive status at a counselling session that the potential sexual partner has been asked to attend as well, with the counsellor noting the disclosure in the client record.
  • Asking one’s potential sexual partner to co-sign a document (which the authors note is “the most unrealistic strategy”).

At what point is unprotected sex a potentially criminal act?

In Scotland, unprotected sex involving a person with HIV (whether or not transmission occurs) is potentially a criminal offence. However, the risk of being prosecuted for ‘HIV exposure’ is extremely low, and would be extremely unlikely if there had been informed consent to the unprotected sex and/or the sex was not high risk.

Although the courts and prosecutorial policy in Scotland does not define ‘high risk’ sex, Scottish prosecutorial guidance does specifically state that they would be unlikely to prosecute someone receiving treatment and who has been given medical advice that there was a low risk of transmission.

It also states that they would be more likely to prosecute someone for ‘HIV exposure’ if they repeatedly had unprotected intercourse, with either the same or multiple partners, without first disclosing that they were living with HIV.

In England, Wales and Northern Ireland, most cases of unprotected sex (with or without the prior 'informed consent' of their partner) that do not result in HIV transmission are not a criminal offence. The exception would be unprotected sex with the specific intent of infecting someone, even if transmission did not occur as a result.

Nevertheless, inappropriate police investigations may still sometimes occur, due to low levels of police awareness of the law and correct procedures.

At what point is protected sex a potentially criminal act?

Most protected sex (i.e. sex with the use of a male or female condom) does not result in HIV transmission. This means that in all UK jurisdictions this would not be a criminal offence even if the sexual partner was unaware of the individual's HIV-positive status prior to sex.

However, condoms can sometimes fail (i.e. break or come off) during intercourse. Should transmission occur, the police might investigate this if the complainant claims they did not explicitly agree to have sex knowing that their sexual partner was HIV positive. The fact that a condom was used (and failed) is extremely difficult to prove: although the only evidence may be the complainant's testimony, a jury may find the complainant more sympathetic or believable than the accused.

Guidance for England and Wales has addressed some of the uncertainty over whether or not condom use without prior disclosure would be considered 'reckless' enough for an individual to be criminally liable should HIV transmission still occur. It states: “…only where it can be shown that the suspect knew that such safeguards were inappropriate will it be likely that the prosecution would be able to prove recklessness.” This means as long as the condom was being used with good faith in its effectiveness an offence is unlikely to have occurred.

Terrence Higgins Trust and NAT recommend that if a condom is found to have failed during sex the best thing to do would be for the HIV-positive person to promptly advise their partner to obtain post-exposure prophylaxis (PEP).2 However, this may mean that the HIV-positive individual must also disclose their HIV-positive status.

It’s worth remembering that the likelihood of a single exposure resulting in transmission is extremely low, particularly if the person with HIV is on treatment with a low or undetectable viral load and/or their sexual partner takes PEP. (See NAM's HIV transmission and testing.)

In the extremely rare circumstance that a broken condom does result in transmission, a prosecution would be extremely unlikely for several reasons:

  • In all parts of the UK, the use of a condom would help demonstrate that the HIV-positive individual was not being reckless.
  • The disclosure of HIV status following sex and recommendation of PEP may be used as a defence against being reckless (although this defence has not been confirmed by a court).
  • Prosecutorial guidance for both England and Wales, and Scotland, specifically statethat the kind of behaviour they will prosecute will usually be ‘sustained’ – i.e. something that happens more than once. This suggests that a one-off event that results in HIV transmission will not be prosecuted.

Can an undiagnosed individual be prosecuted if they didn’t know they were HIV positive at the time?

In most cases, the prosecution will have to prove that the accused knew that they were HIV positive when the sexual act(s) took place. Most people will only ‘know’ they are infected once they have been diagnosed. Evidence of this can be obtained via medical records, including potentially anonymous records at a genitourinary medicine (GUM)/sexual health clinic.

There may be exceptional circumstances in which a person might be seen as having ‘deliberately closed their mind’ to the possibility that they were HIV positive. Examples suggested by the CPS include when someone has refused to test despite specific advice to do so by a doctor, or does not get a confirmatory blood test following a preliminary reactive result with a rapid test. Another example is if a previous sexual partner has been diagnosed with HIV in circumstances which clearly mean that the sexual partner was likely to have been infected by accused.

What exactly does being 'reckless' mean in the context of HIV transmission?

In all parts of the UK, the law considers a person to be 'reckless' if they consciously take an unjustifiable risk. In the context of HIV transmission this means the HIV-positive person did not intend for their sexual partner to get HIV, but did not try to stop it happening.

To be considered 'reckless', therefore, the prosecution would have to prove that the accused:

  • had knowledge of their HIV-positive status (although see the exception of ‘deliberately closed their mind’ above)
  • understood he or she was infectious
  • understood how HIV is transmitted
  • did not use ‘appropriate safeguards’ to prevent this from happening.

A defence to recklessness in all parts of the UK would be informed consent to the risk of HIV transmission from the HIV-negative individual, usually obtained by the HIV-positive individual telling the other person about their HIV status before sex took place.

Evidence regarding knowledge of HIV-positive status, infectiousness and how HIV is transmitted would either be obtained from medical notes, or direct testimony from the accused's doctor or health adviser who delivered post-testing counselling. However, the CPS guidance acknowledges that people are often shocked when first diagnosed and do not necessarily take in what they are told, and may require evidence that an HIV-positive individual had been counselled further – even repeatedly – regarding their sexual risk-taking.

Is effective HIV treatment and an undetectable viral load an ‘appropropriate safeguard’?

The CPS policy and guidance for England and Wales is somewhat equivocal on this point. On the one hand it notes that, “medical opinion on the reduction of the risk of infection is not settled, and evidence of the actual taking of medication in accordance with medical instructions may not be as clear-cut as evidence of the use of other safeguards such as condoms.”

However, it also suggests that this may be used as a defence to recklessness. “It may be argued,” it states, “that taking medication may, in some circumstances, be as effective a safeguard as, for example, the use of a condom in reducing risk and therefore negating recklessness.”

Therefore, if the accused had an undetectable viral load on antiretroviral medication and had been counselled by their healthcare professional that this was an effective risk-reduction method, it may mean that the jury would find they were not reckless even if transmission occurred.

The COPFS guidance for Scotland states: “With regard to HIV, there is a body of medical opinion that there is minimal or negligible risk of transmission when plasma viral load is below 50.” It specifically notes that evidence that the accused was “receiving treatment and been given medical advice that there is a low risk of transmission or that there was only a negligible risk of transmission in some situations or for certain sexual acts” will mean that it is unlikely that the requisite degree of recklessness would be established.

Can confidential medical records be used in court?

Whereas communications between lawyer and client are ‘privileged’ in the sense that the information that is shared can be legally withheld from investigators and from the court record, this is not the case for medical records. Clinical notes, and other confidential information, can be obtained and used in criminal cases as long as it is materially relevant to either the defence or prosecution.

However, police have no automatic right to see clinicians’ notes about patients. If they wish to see notes, they must either request the patient’s permission or obtain a court order.

Prior to being charged, if the accused declines to provide a blood sample and/or access to their medical records, their doctor can provide these to the police under very specific circumstances. This would be when the doctor considers it justifiable in the public interest to disclose the information voluntarily, without the accused's consent, as outlined in the General Medical Council's Confidentiality Guidance.3

Where this is not the case, such evidence can be obtained with a court order after the accused is charged.

In light of the potential for information to be misused, advocates for people with HIV have recommended that anyone being investigated in cases of alleged HIV exposure or transmission should not grant access to personal medical records without first obtaining legal advice.4

Although complainants (those making the accusation) may perhaps feel less concerned than defendants about others gaining access to their medical records, they should be aware of the potential for everything in the records to be used for the investigation and/or be made public during a trial, including information that weakens their case.

How can it be proven that one person infected another?

Proving criminal HIV transmission requires the use of a combination of types of evidence:

  • scientific evidence (known as 'virological evidence') that examines the relationship between the HIV of the accused and the HIV of the complainant(s)
  • medical evidence, including sexual history, of both the accused and the complainant(s), obtained from clinical records and/or testimony.

It may be difficult to prove that one person infected another beyond a reasonable doubt because of alternative explanations as to how HIV infection could have occurred.5

Is the defendant the source of the complainant’s HIV infection?

Could the complainant have become infected with HIV by someone else, or not via sexual activity at all (e.g. through injecting drug use or during a past medical procedure)?

This would require investigating the medical and behavioural history of the complainant. Someone who has recently been diagnosed HIV positive may well be mistaken regarding the source of their infection. Just because they have discovered that their most recent sexual partner is HIV positive and had not informed them does not mean that they necessarily acquired their own infection this way. A study that used phylogenetic analysis to confirm or disprove whether someone who had named the source of their infection during routine contact tracing found that 60 to 70% of the time the assumed source could not have been the source of the infection.6

Does the timing of events support the plausibility of the accusation?

Did the alleged HIV transmission take place before or after the person being investigated was made aware of his or her HIV status? Did the alleged HIV transmission take place before or after the complainant was made aware of the HIV status of the person being investigated?

Medical histories can suggest – but not definitely prove – timing, and may help corroborate testimony relating to the defendant’s intent and the complainant’s awareness of the risk of becoming infected.

Can the direction of transmission be proven?

Instead of the defendant transmitting HIV to the complainant, might the complainant actually have been the source of the defendant’s HIV infection? Does evidence exist to prove or disprove either scenario?

Again, one source of evidence may be the medical and behavioural histories of both the person being investigated and the complainant.

Limitations of phylogenetic analysis

Phylogenetic analysis examines very small differences in the RNA of HIV strains from different sources in order to estimate how closely these strains are genetically related. A very important part of the CPS guidance concerns the limitations of phylogenetic analysis as evidence that 'proves' that one person infected another. It will be harder to prove this if the person making the complaint has had more than one sexual partner (or another HIV infection risk) since their last negative HIV test. By taking blood samples from both people involved, if the virus strains are not very similar, it may be possible to say with some certainty that one person did not infect the other.

If samples are very similar, however, this is considered to be just one piece of evidence supporting the claim that one person infected the other. It is an important piece of evidence, but it cannot be used as proof on its own. Other evidence will include the medical and sexual history (for example, from medical records or diaries) of both the person making the complaint and the person who is accused, which will be used to try to understand the timing of both people's HIV diagnoses and whether the person making the complaint could have been infected in another way.

Consequently, before any court case begins, the police should ideally investigate the past sexual contacts of both accused and complainant(s), to decide whether there is enough evidence for a trial to prove 'beyond reasonable doubt' that it was the accused, and not someone else, who infected the complainant.

Are there any other laws potentially regulating the behaviour of people living with HIV?

In England and Wales, following a conviction it is possible for the court to place limitations on a defendant's future behaviour, through a Sexual Offences Prevention Order (SOPO). For example the individual may be required to disclose their HIV status before sex with a new sexual partner or be required to use a condom. Although SOPOs have been used in two cases7, the 2011 update of the CPS guidance states that a SOPO is unlikely to be an “appropriate order in a case involving the sexual transmission of infection”.8

However, it may be possible for a court to consider making an Anti-Social Behaviour Order (ASBO) to mandate disclosure or condom use, or both.

An ASBO should not be used if the complainant was in a co-habiting relationship with the accused. The guidance states that an ASBO can only be made on conviction if a court considers: “that the offender has acted... in a manner that caused or was likely to cause harassment, alarm or distress to one or more persons not of the same household as himself”.

HIV is also subject to the Public Health (Control of Disease) Act 1984, which was recently amended by the Health and Social Care Act 2008. These have been implemented in both Health Protection (Local Authority Powers) Regulations 2010 and the Health Protection (Part 2A Orders) Regulations 2010, which only apply to England.

The (English) Department of Health has provided guidance regarding how these powers should be used in people living with HIV.9 Under these English public-health laws, a justice of the peace can, under "exceptional circumstances", make a Part 2A Order requiring someone with HIV who is thought to be placing others at risk to:

  • provide information or answer questions about their health or sexual partners.
  • undergo medical examination (although they cannot be forced to take antiretroviral treatment).
  • have their health monitored and the results reported.
  • attend training or advice sessions on how to reduce the risk of infecting others.
  • be subject to restrictions on where they go or who they have contact with.
  • be taken and detained in hospital.
  • be kept in isolation or quarantine.

The guidance makes it clear that Part 2A orders are only to be used as a last resort and are "not a tool for managing long-term problems". It clarifies that they are not meant to change the current culture of confidentiality within sexual health services and should not be a routine part of managing people living with HIV who present with evidence of ongoing unsafe sex. If a Part 2A order is being considered, advice should be sought from the treating clinician and clinic director as to the possible consequences of such an order, with confidentiality respected at all times.

Since these powers are new, there is limited information regarding the circumstances in which they have been applied. However, any application for, or use of, these powers must be reported to Public Health England (formerly the Health Protection Agency), which says that the powers have been used 15 times in 2010-2012. Almost all cases related to individuals with tuberculosis, but there was one case of a person with HIV. Further details have not been provided.

What should I do if I find myself accused of criminal HIV transmission or exposure?

  • Get support from an HIV organisation with experience of dealing with these issues. Terrence Higgins Trust (THT Direct, 0808 802 1221) has considerable experience.
  • Don’t be rushed into hasty action. In dealing with the police, do not give a statement, say that you are responsible for the person’s HIV infection or give permission for medical records to be accessed without getting expert legal advice. All these actions have serious implications.
  • Get the advice of a solicitor with experience of the issue. THT can recommend solicitors. Ask possible solicitors if they have worked on this sort of case before. If they have not, make sure they are in contact with experts in this area of law who can provide them with resources and advice. Again, THT can put solicitors in contact with experts.
  • Solicitors may be able to arrange legal aid to cover their costs.


  1. HIV and AIDS Legal Clinic (Ontario) et al. HIV disclosure: a legal guide for gay men in Canada. HIV and AIDS Legal Clinic (Ontario), Ontario’s Gay Men’s Sexual Health Alliance and Canadian AIDS Treatment Information Exchange. Available at:, 2009
  2. National AIDS Trust (NAT)/ Terrence Higgins Trust (THT) Prosecutions for HIV Transmission: a guide for people living with HIV in England and Wales. London: NAT/THT. Available at:, 2009
  3. General Medical Council Confidentiality: disclosing information about serious communicable diseases. Available at: (date accessed 20 August 2013) , 2009
  4. BHIVA and BASHH HIV Transmission, the Law and the Work of the Clinical Team. Available at:, January 2013
  5. Bernard EJ et al. HIV Forensics: the use of phylogenetic analysis as evidence in criminal investigation of HIV transmission. London: NAM/NAT. Available at:, 2007
  6. Resik S et al. Limitations to contact tracing and phylogenetic analysis in establishing HIV type 1 transmission networks in Cuba. AIDS Research and Human Retroviruses 23 (3); 347-356, 2007
  7. See:,
  8. Crown Prosecution Service Intentional or Reckless Sexual Transmission of Infection: Legal guidance. Available at:, July 2011
  9. Health Protection Agency Health protection legislation guidance 2010. Available at:, 2010
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.
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