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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