Here's the "official" English translation of the Swiss Federal Commission for HIV/AIDS consensus statement.
HIV-infected persons on effective anti-retroviral therapy are sexually non-infectious
P. Vernazza, B. Hirschel, E. Bernasconi
Summary
The Federal Commission for HIV/AIDS, following the proposal of the Sub-commission on Clinical and Therapeutic Aspects, and after review of the medical literature and extensive discussion, resolves that:
An HIV-infected person on anti-retroviral therapy with completely suppressed viremia („effective ART“) is not sexually infectious, i.e. cannot propagate HIV through sexual contact.
This statement is valid if
• this person is compliant with ART, whose effect must be evaluated regularly by the treating physician, and
• the viral load has been suppressed (non-detectable) since at least six months ago, and
• there are no other sexually transmitted diseases
a) Transmission depends on the viral load.
We define „effective ART“ as fully suppressive, stable treatment, with a viral load below the limits of detection in plasma (< 40 copies/ml). Treatment is considered "stable" once the viral load has been undetectable for at least six months. The Commission realizes that medical and biologic data available today do not permit proof that HIV-infection during effective ART is impossible, because the non-occurrence of an improbable event cannot be proven. If no transmission events were observed among 100 couples followed for two years, for instance, there might still be some such events if 10'000 couples are followed for 10 years. The situation is analogous to 1986, when the statement “HIV cannot be transmitted by kissing” was publicized. This statement cannot be proven, but after 20 years’ experience its accuracy appears highly plausible.
Concerning the statement "an HIV-infected person on anti-retroviral therapy with completely suppressed viremia („effective ART“) cannot propagate HIV through sexual contact” however, the evidence is much better than what was available in 1986 regarding kissing.
1) In sero-discordant couples (one person seropositive, the other seronegative), the risk of transmission depends on the viral load of the HIV-infected partner, see Figure 1 from reference (1).
2) In a prospective study of 393 heterosexual sero-discordant couples there were no infections among partners of persons on ART, compared to a rate of transmission of 8.6% among partners of untreated patients (3).
3) In another prospective study of 92 sero-discordant couples, where in 41 cases the HIV-positive partner had started therapy, there were 6 infections. All these occurred in partners of untreated patients (3).
4) Among 62 sero-discordant couples, where the male partner was HIV positive and on ART, with unprotected sex in order to conceive, there was no transmission (4).
5) Transmission from mother to newborn also depends on the maternal viral load, and did not occur in pregnancies where the maternal viral load was below 1000 copies per ml. If the maternal viral load is higher, transmission can be prevented by ART (5-8).
b) Effective ART eliminates virus from genital secretions
HIV-RNA, measured in sperm, declines below the limits of detection during ART (15-17). The viral load (HIV-RNA) in female genital secretions is, as a rule, below the plasma VL and below the limits of detection during effective ART. As a rule, it rises after, not before, an increase in plasma VL (18). Cell-associated viral genomes are present in genital secretions, even during ART (15, 19-21). But these are not functional virions. HIV-containing cells in sperm lack markers of viral proliferations such as circular LTR-DNA (22).
The concentration of HIV RNA in sperm (sperm VL) correlates with the risk of transmission. Transmission risk declines towards 0 with falling sperm VL, see Figure 2. These data indicate that the risk of transmission is greatly decreased by ART.
c) Exceptions and caveats
• After a few days or weeks of discontinuation of ART, plasma viral load rises rapidly. There is at least one case report of transmission during this rebound (14)
• In patients without ART, sexually transmitted diseases (STDs, for instance urethritis or genital ulcer disease) increase the genital VL; it falls again after treatment of STD (24). In a patient with urethritis, sperm VL can rise slightly even while patient is receiving effective ART. This rise is small, however, much smaller that the rise observed in patients without ART.
d) Conclusion
• During effective ART, free virus is absent from blood and genital secretions. Epidemiologic and biologic data indicate that during such treatment, there is no relevant risk of transmission.
• Residual risk can not be scientifically excluded, but is, in the judgment of the Commission, negligibly small
References
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