There is evidence (see above) of some groups of gay men
knowing, from the late 1990s onwards, that people with an undetectable HIV
viral load were much less infectious, and were using this knowledge in sexual
decision-making. Public discussion of this became much more high profile after
a paper was issued by the Swiss Federal Commission for HIV/AIDS in January
2008.
The authors of the ‘Swiss Statement’ have since said that
they were surprised at the amount of attention their paper got and the global
discussion it set off. It was intended purely as an in-country guideline
directed at doctors and, significantly, at legal professionals. Much of the
motivation for the statement lay in the fact that Switzerland had prosecuted
and convicted a number of HIV-positive people for exposing partners to HIV, and
the doctors wanted there to be a statement saying that HIV-positive people
posed no risk to their partners if they were undetectable on stable
antiretroviral therapy. They stated that unprotected sex between a positive
person on antiretroviral treatment, and without an STI, and an HIV-negative
person did not comply with the criteria for an “attempt at propagation of a
dangerous disease” in the Swiss penal code nor for “an attempt to engender
grievous bodily harm”.
Although the statement purely concerns the position of
individuals and was not connected with the mathematical-modelling studies that
were starting to be issued which looked at the possibility of using viral
control as a prevention measure, it was significant because it transformed the
discussion around viral undetectability and infectiousness from one in which
using viral load status to inform sexual-risk decisions was seen as dangerous,
and a rationalisation for having unprotected sex, to one in which it became
possible to talk about its legitimate use as a prevention measure.
Nonetheless, the statement caused widespread concern amongst
some prevention and public health advocates who felt it was based on weak
evidence in some areas and risked undermining people’s efforts to maintain and
promote condom-based safer sex.
The statement said that people with HIV are not sexually infectious (“ne transmettent pas le VIH par voie
sexuelle”), as long as the following conditions are met:
- The HIV-positive individual takes antiretroviral
therapy consistently and as prescribed and is regularly followed by his/her
doctor.
- Viral load is 'undetectable' and has been so for
at least six months.
- The HIV-positive individual does not have any
STIs.
The original statement made no distinction between vaginal
and anal sex, though all the evidence the writers cited in support of the
statement concerned heterosexual transmission, such as the Rakai study, and
they have since said that the statement only covered heterosexual transmission.1
The statement had five co-authors, four of them
Switzerland’s foremost HIV experts: Professor Pietro Vernazza, of the Cantonal
Hospital in St Gallen, and President of the Swiss Federal Commission for
HIV/AIDS; Professor Bernard Hirschel from Geneva University Hospital; Dr Enos
Bernasconi of the Lugano Regional Hospital; and Dr Markus Flepp, President of
the Swiss Federal Office of Public Health’s Sub-committee on the clinical and
therapeutic aspects of HIV/AIDS. Significantly, its fifth author was a
community activist, François
Wasserfallen of the European AIDS Treatment Group, thus ensuring that community
‘buy-in’ for the statement was present from the start.
The headline statement says that “after review of the
medical literature and extensive discussion” the Swiss Federal Commission for
HIV/AIDS resolves that, “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.”
The Commission states 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".
However, they emphasise that, "Couples must understand
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 relationship."
They add that heterosexual women will have to consider
eventual interactions between contraceptives and antiretrovirals before
considering stopping using condoms. They also say that insemination via
sperm washing is no longer indicated when "antiretroviral treatment is
efficient."
The Commission goes on to say that it "is not for the
time being, considering recommendations that HIV-positive individuals start
treatment purely
for preventative measures." Aside from the cost involved, they argue, it
cannot be certain that HIV-positive people would be sufficiently motivated to
follow, and apply to the letter, antiretroviral treatment on a long-term basis
without medical indications. They note that poor adherence is likely to
facilitate the development of resistance, and that, therefore, antiretroviral
therapy as prevention is indicated only in "exceptional circumstances for
extremely motivated patients".
The Commission also says that their statement should not
change prevention strategies currently taking place in Switzerland. With the exception of
stable HIV-positive couples where HIV-positivity and the efficacy of
antiretroviral therapy can be established, measures to protect oneself must be
followed at all times. "People who are not in a stable relationship must
protect themselves," they note, "as they would not be able to verify
whether their partner is positive or on efficient antiretroviral therapy."
At a meeting in Mexico
City in August 2008,2 Pietro Vernazza clarified
some aspects of the statement. “We never thought of it as a statement that was
to be delivered worldwide,” he said, but rather “it was meant only to be
delivered to Swiss physicians to help them discuss sexual risk-taking with
their patients and their steady partners.” He regretted the “ne transmettent
pas” in the statement’s title and said that this absolute phrasing was
‘misleading’ in that it appeared to rule out the possibility of any residual
risk.
“We also made it
clear that the only person who can assess perfect adherence and regular
check-ups would be a steady partner, and that it should only be the informed
[HIV-negative] partner who could assess the risks for themselves.” The
statement, he said, was “good news for a small number of people, but [for
everyone else] prevention messages remain unchanged”.
Nonetheless, he
defended the applicability of the statement at least to heterosexual couples in
the light of subsequent research, including the Wilson paper in The Lancet,3 which said that
gay male couples where the HIV-positive partner was on treatment could reduce
their transmission risk to virtually zero if they also used condoms, and said
the estimated residual risk to heterosexual couples where the HIV-positive
partner was on treatment was of the same order as other possible, but unlikely,
hazards such as the risk of dying in an air crash or avalanche.