Expert statements and guidance for individuals

Published: 12 August 2013

The ‘Swiss statement’ (2008)

In January 2008, the Swiss National AIDS Commission issued a statement in French and German1 aimed at clinicians in Switzerland. Co-authored by four of the country’s foremost HIV experts, it has since become known as the ‘Swiss statement'.

This assessment of the biological, epidemiological and ecological evidence available at the time about the impact of reduced viral load due to antiretroviral therapy on the individual risk of sexual transmission stated: "An HIV-infected person on antiretroviral therapy with completely suppressed viraemia (“effective ART”) is not sexually infectious, i.e. cannot transmit HIV through sexual contact.”

It went on to say that this statement was valid as long as:

  • The person adheres to antiretroviral therapy, the effects of which must be evaluated regularly by the treating physician; and
  • The viral load has been suppressed below the limits of detection (i.e. below 40 copies/ml) for at least six months; and
  • There are no other sexually transmitted infections (STIs).

Subsequent clarification has established the Swiss did not actually mean to state there is zero risk under these circumstances, but that the risk of HIV transmission is within the normal bounds of everyday risks which they estimated to be in the region of 1 in 100,000.2

The statement did not recommend any change in policy regarding the use of treatment to prevent new infections on a population level, but stated that an HIV-positive person in a stable relationship with an HIV-negative partner, who follows their antiretroviral treatment consistently and as prescribed and who does not have an STI, is "not putting their partner at risk of transmission by sexual contact".

"Couples must understand," they wrote, "that adherence will become omnipresent in their relationship when they decide not to use protection, and due to the importance of STIs, rules must be defined for sexual contacts outside of the relationship."

"The same goes for people who are not in a stable relationship," they noted, recommending that condoms should still be used outside of a mutually monogamous relationship due to the importance of STIs.

They added that heterosexual women would have to consider possible interactions between contraceptives and antiretrovirals before considering stopping using condoms. They also said that insemination via sperm washing would no longer be indicated if "antiretroviral treatment is efficient".

‘Doing without condoms during potent ART’ (2008)

To coincide with the ‘Swiss statement’, the Swiss National AIDS Commission, in collaboration with the civil society organisation Swiss AIDS Federation (Aids-Hilfe Schweiz) produced detailed guidance for healthcare workers and community-based counsellors regarding how to counsel people with HIV in Switzerland on how to reduce their risk of HIV transmission in ways other than 100% condom use.3

It remains the most detailed guidance produced to date for individuals, covering information for couples of different HIV status, HIV-positive couples and HIV-positive, HIV-negative or untested individuals.

It recommends the following:

Couples of different HIV status should undergo intensive couples counselling regarding the risks and benefits of unprotected sex when the HIV-positive partner is on effective treatment.

  • Physicians should deliver detailed information (covering pre-conditions for potent ART, medical check-up frequencies, residual risks, STIs, contraception) to both partners.
  • Further information regarding psychological issues, treatment adherence issues, the legal situation, and shared responsibility within the partnership for HIV transmission (although it also stressed that the HIV-negative partner should make the final decision to forgo condoms) should be delivered as part of community-based counselling.
  • When having sex outside of the relationship with casual contacts, anonymous sex or in a new relationship where neither is certain of the other's HIV status, condoms should still be used.

Couples in which both partners are HIV positive should undergo counselling similar to that for couples of different HIV status, with an additional discussion of superinfection risk and a focus on shared responsibility for deciding whether or not to forgo condoms.

HIV-positive, HIV-negative or untested individuals who are having sex outside of relationships should be counselled to continue to rely on condom use to protect themselves. The counselling guidelines highlight that individuals are responsible for their own protection in such circumstances and cannot rely on the credibility of information they receive from their sexual partners regarding HIV status, therapy and its success.

UK guidelines for the sexual and reproductive health (SRH) of people living with HIV (2008)

Guidelines on the sexual and reproductive health of people with HIV, produced by the British HIV Association (BHIVA), the British Association of Sexual Health and HIV (BASHH) and the Faculty of Sexual and Reproductive Health of the Royal College of Obstetricians and Gynaecologists (FSRH), published in October 2008,4 included a section discussing some of the individual HIV transmission risk issues raised by the ‘Swiss statement’.

The short section addressing the ‘Swiss statement’ acknowledged the “compelling evidence” concerning effective treatment in reducing individual risk for vaginal or oral sex, but noted that the writing committee “cannot fully endorse the Swiss consensus statement” for anal sex due to a lack of scientific evidence.

It recommended that detailed individual counselling focusing on harm reduction (rather than harm elimination) should be available for all HIV-positive individuals in long-term relationships who wish to consider unprotected sexual intercourse with people of the same or different status relationships, for example, for the purposes of natural conception. However, in most circumstances, counselling and advice should continue to promote the use of condoms to reduce the transmission risk of HIV and other STIs.

UK PEP guidelines (2011)

In 2011, UK guidelines for the use of post-exposure prophylaxis (PEP) following sexual HIV exposure issued by the British Association for Sexual Health and HIV (BASHH) and the British HIV Association (BHIVA) recommended that PEP should no longer be provided in a number of situations where the ‘source partner’ is known to be HIV positive and to have an undetectable viral load.5

The authors point to data showing that in many situations, an undetectable viral load makes HIV transmission highly unlikely and so PEP would be unnecessary. After sexual contact with a person with diagnosed HIV and an undetectable viral load, PEP is no longer recommended if the sexual activity was unprotected vaginal intercourse, unprotected insertive anal intercourse or oral sex. But PEP is still recommended following unprotected receptive anal intercourse.

The table below summarises the recommendations:.


HIV status of the person’s sexual partner (‘the source’)


HIV positive

HIV positive with undetectable viral load

Unknown HIV status, thought to be an African migrant or a gay man

Unknown HIV status, NOT from a high prevalence group

Receptive anal sex





Insertive anal sex





Vaginal sex (male or female partner)





Fellatio (i.e. taking a penis in the mouth), with ejaculation





All other forms of oral sex





Splash of semen into eye





Sharing of injecting equipment





Human bite





Contact with a needle or syringe discarded in a public place





* When the guidelines say that PEP should be ‘considered’, it should only be given if there is an additional factor which increases the likelihood of transmission, such as particularly high local HIV prevalence, a sexually transmitted infection, acute HIV infection in the source partner, sexual assault or trauma, bleeding (including menstruation) or – in the case of vaginal sex – the HIV-negative male partner not being circumcised.

UK safer sex guidelines (2012)

In July 2012, British Association for Sexual Health and HIV (BASHH) and the British HIV Association (BHIVA) produced updated UK national guidelines on safer sex advice.6

The guidelines provide evidence-based guidance on the content of safer sex advice provided in sexual health (GUM) clinics, HIV clinics, primary care and other healthcare settings.

The guidance briefly covers the impact of antiretroviral treatment to prevent HIV transmission, noting that an undetectable blood plasma viral load cannot always be considered as a marker of an undetectable seminal viral load, that there have been case reports of HIV transmission with undetectable plasma viral load, and that the residual transmission risk is likely to be higher for anal sex than for vaginal sex.

It recommends highlighting the following information to people living with HIV, their sexual partners and those from groups with higher incidence of HIV infection:

  • Taking effective antiretroviral therapy and having an undetectable viral load in blood significantly reduces the risk of HIV transmission.

Even with an undetectable viral load, there is still a small, residual risk of HIV transmission.

  • This residual risk is likely to be higher for anal sex than for vaginal or oral sex.
  • The risk is greater if antiretroviral treatment doses are missed or are late, or if either partner has a sexually transmitted infection. The risk can be reduced by using condoms and having regular STI screens.
  • Serodiscordant couples should receive detailed expert counselling and support on transmission risks and other relevant issues.
  • Discussion regarding starting antiretroviral therapy early in order to reduce the risk of HIV transmission should be considered as part of safer sex counselling for some people living with HIV.

BASHH has also produced a patient information leaflet that summarises the safer sex guidance and which includes similar information.7

UK treatment guidelines (2012)

The 2012 HIV treatment guidelines produced by the British HIV Association (BHIVA) recommended for the first time that doctors should discuss the evidence for the effectiveness of antiretroviral treatment as prevention with all patients with HIV, and that it should be offered to those who want to protect their partners from the risk of HIV infection – even if they have no immediate clinical need for treatment themselves.8

All patients should be informed of this evidence, the guidelines say, but no patient should be forced to take treatment for this reason. Patients should also be told that the evidence of a lower risk of transmission on treatment mainly relates to vaginal sex, not anal sex, and that use of condoms will continue to protect against sexually transmitted infections as well as lowering any residual risk of HIV transmission.


UK BHIVA/EAGA statement (2013)

In January 2013, the British HIV Association (BHIVA) and the Department of Health’s Expert Advisory Group on AIDS (EAGA) published a position statement on the use of HIV treatment by people with HIV to reduce the risk of transmission.9

The document provides UK health professionals with a consensus statement, developed by UK experts, which can be used to guide discussions with individuals. Clinicians, epidemiologists, policy experts and HIV-positive people contributed to the document.

Key points include the following:

As effective as condoms

The statement notes that there is now conclusive randomised clinical trial evidence, from the HPTN 052 trial, to show that transmission of HIV through vaginal sex is significantly reduced when an HIV-positive person is taking effective antiretroviral therapy.

“The observed reduction in HIV transmission in a clinical trial setting demonstrates that successful ART use by the person who is HIV positive is as effective as consistent condom use in limiting viral transmission,” it says.

The document includes some explanatory notes, which point out that there has never been a randomised controlled trial of the efficacy of condom use, compared to non-use. For that reason, there are no figures that can be directly compared. However, meta-analyses of observational studies of serodiscordant couples who maintained 100% condom use have found the strategy to be about 80% effective in reducing HIV infection.

Necessary conditions

The document states that the transmission risk during vaginal intercourse will be “extremely low”, provided certain conditions are fulfilled:

  • There are no sexually transmitted infections in either partner. (The document clarifies requirements for STI screening, including following sexual relationships outside a primary partnership.)
  • The person with HIV has had a sustained blood plasma viral load below 50 copies/ml for more than six months, including the most recent test.
  • Viral load testing occurs every three to four months (i.e. more regularly than in standard clinical care).

In the document’s explanatory notes, it is explained that in HPTN 052 there was a single confirmed case of HIV transmission from a person on treatment. This individual had only recently begun treatment and would not have met the UK position statement’s requirement for an undetectable viral load for at least six months. The authors say that this justifies the use of the phrase “extremely low risk”. They clarify that this is not the same as “zero risk”. Moreover, with the data that are available, it is not possible to give accurate and meaningful figures for the risk of transmission during a single sexual act.

Anal intercourse

The published research was primarily done with heterosexual couples and is assumed to relate primarily to vaginal intercourse. Data are not available for anal intercourse, either between men, or between men and women. “However, it is expert opinion that an extremely low risk of transmission can also be anticipated for these practices, provided the same conditions stated above are met,” according to the statement.

Discussion with people with HIV

Healthcare professionals should discuss the impact of treatment on sexual transmission with all people living with HIV. For people not currently on therapy, the possibility of starting treatment in order to reduce transmission risk should be discussed.

Limitations of ART

The position statement notes that no single prevention method can completely prevent HIV transmission. Moreover, antiretroviral treatment has no effect on other sexually transmitted infections, whereas condoms can prevent their spread.

UK guidance on sperm washing (2013)

In February 2013, the National Institute for Health and Clinical Excellence (NICE) produced guidance on fertility treatment which stated that sperm washing may no longer be necessary for couples where the man has HIV and the woman does not. As long as the man is on effective antiretroviral treatment and unprotected sex is limited to days when his partner is ovulating, “sperm washing may not further reduce the risk of infection”.10

They propose criteria similar to that of the Swiss and EAGA/BHIVA statements, to determine whether unprotected vaginal intercourse would be an appropriate way to conceive. All the following conditions should be met:

  • Unprotected intercourse is limited to the time of ovulation.
  • The man adheres to antiretroviral therapy.
  • The man has a blood plasma viral load of less than 50 copies/ml.
  • There are no other sexually transmitted infections.

Should the man have problems with adherence to antiretroviral therapy and/or if his plasma viral load were to become detectable, the guidance recommends that his seminal viral load be tested. If HIV is undetectable in semen, doctors should inform the couple that the risk of HIV transmission during timed unprotected intercourse is “negligible”.

In situations other than these, sperm washing should still be recommended. Moreover, the document acknowledges that some couples may still be anxious about the risk of HIV transmission during unprotected intercourse when the male partner is on effective treatment. In such a case, sperm washing would still be considered.

Related Links


  1. Vernazza P et al. Les personnes séropositives ne souffrant d’aucune autre MST et suivant un traitment antirétroviral efficace ne transmettent pas le VIH par voie sexuelle. Bulletin des médecins suisses 89 (5), (English translation, including translator’s affidavit, available at: Date accessed: 21 July 2013), 30 January 2008
  2. Bernard EJ Swiss statement that “undetectable equals uninfectious” creates more controversy in Mexico City. Available online at:, 5 August 2008
  3. Swiss AIDS Federation Advice Manual - Doing without condoms during potent ART. 30 January, 2008
  4. Fakoya A et al. British HIV Association, BASHH and FSRH guidelines for the management of the sexual and reproductive health of people living with HIV infection 2008 HIV Medicine 9: 681-720, 2008
  5. Benn P et al. UK guideline for the use of post-exposure prophylaxis for HIV following sexual exposure. International Journal of STD & AIDS, 22: 695-708, 2011
  6. Clutterbuck DJ et al. on behalf of the Clinical Effectiveness Group of the British Association for Sexual Health and HIV (BASHH) and the British HIV Association (BHIVA) UK national guidelines on safer sex advice. July, 2012
  7. BASHH A guide to safer sex. BASHH, 2012
  8. Williams I et al. British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2012. HIV Med 13 Suppl 2:1-85, 2012
  9. British HIV Association (BHIVA) and Expert Advisory Group on AIDS (EAGA) Position statement on the use of antiretroviral therapy to reduce HIV transmission. BHIVA/EAGA, 2013
  10. National Institute for Health and Care Excellence Fertility: Assessment and treatment for people with fertility problems CG156. February, 2013
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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