A study published in the British Medical Journal reports
that receipt of antiretroviral treatment (ART) was associated with an absence
of HIV transmission among discordant couples in Spain. The authors acknowledge
that their findings should be interpreted with caution due to several
limitations, particularly a high rate of loss to follow-up during the
prospective part of the study and relatively few transmission endpoints (5
seroconversions in total). But the results appear consistent with another larger
prospective discordant couples study that was reported at CROI earlier this year; in that case, an analysis of the effect of
ART found that out of 103 transmission events, in only one instance was the
HIV-positive partner on treatment and the regimen had been initiated just 18 days
prior to the previously uninfected partner’s first positive test.
Published 14 May 2010, doi:10.1136/bmj.c2205
Cite this as: BMJ 2010;340:c2205
Research (access to full text is free)
Jorge Del Romero, clinical researcher1, Jesús Castilla,
consultant medical epidemiologist2, Victoria Hernando, epidemiologist3, Carmen
Rodríguez, research scientist1, Soledad García, clinical researcher1
1 Centro Sanitario Sandoval, Comunidad de Madrid, Spain, 2
Instituto de Salud Pública de Navarra, CIBER de Epidemiología y Salud Pública,
Pamplona, Spain, 3 Centro Nacional de Epidemiología, Instituto de Salud Carlos
III, CIBER de Epidemiología y Salud Pública, Madrid, Spain
Abstract
Objective: To estimate the risk and probability of heterosexual
transmission of HIV-1 from infected people taking combined antiretroviral
treatment.
Design: Cross sectional and prospective cohort studies.
Setting: HIV clinic in Madrid, Spain.
Participants: Stable heterosexual couples with one partner
with HIV-1 infection (index partner) and the other reporting this sexual
relationship as the only risk exposure.
Main outcome measures: HIV seroprevalence in non-index
partners at enrolment and seroconversions in follow-up according to
antiretroviral treatment taken by the index partner.
Results: In 476 couples in which the index partner was not
taking antiretroviral treatment, HIV seroprevalence at enrolment in non-index
partners was 9.2% (n=44), whereas in 149 couples in which the index partner was
taking combined antiretroviral therapy no partner was infected (P<0.001).
During follow-up, the 341 serodiscordant couples in which the index partner was
not taking antiretroviral treatment had about 11 000 acts of intercourse
without condoms, 50 natural pregnancies, and five HIV seroconversions (0.0004
per unprotected intercourse; 95% confidence interval 0.0001 to 0.0010); 294 of
these couples always used condoms, accounting for about 42 000 acts of
intercourse, 136 risk exposures from condom failure, and one HIV seroconversion.
The relative risk associated with condom use was 0.07 (0.01 to 0.58). In 144
couples the index partner was taking combined antiretroviral treatment; they
accounted for over 7000 unprotected acts of intercourse and 47 natural
pregnancies but no HIV seroconversion (0 to 0.0005 per unprotected
intercourse).
Conclusions: The heterosexual infectivity of HIV-1 in
individuals taking effective antiretroviral treatment is low. Avoidance of
unprotected intercourse and receipt of antiretroviral treatment by the infected
partner in accordance with protocols are complementary measures to prevent HIV
transmission.
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