The British HIV Association (BHIVA) and the Department of
Health’s Expert Advisory Group on AIDS (EAGA) published this week a position
statement on the use of HIV treatment by people with HIV to reduce the risk of
transmission. For the first time, the document provides 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. The key points are outlined
below.
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 (ART). In this trial, early treatment reduced HIV
transmission to an uninfected partner by 96%.
“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 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 ART 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 ART
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.