Paper # 1038|
Seroadaptive Tactics Adopted by HIV+ MSM Can Contribute to Profound and Sustained Reductions in HIV Transmission Risk following HIV Diagnosis
Snigdha Vallabhaneni*1, L Loeb1, L Bragg2, J McConnell2, W Hartogensis1, R Grant2, F Hecht1, and C Pilcher1
1Univ of California, San Francisco, US and 2Gladstone Inst of Virology and Immunology, San Francisco, CA, US
Background: Previous studies have suggested that
initial reductions in risk behavior after HIV diagnosis are not sustained. We
investigated how seroadaptive tactics, including fewer total partners, serodiscordant
partners, and “risk partnerships” (defined as insertive unprotected anal
intercourse with an HIV– or partners unknown status), adopted by HIV+
men who have sex with men (MSM) influence HIV transmission risk over time.
Methods: MSM with acute/recent (<6 months) HIV
infection were enrolled from 1998 to 2010 into the OPTIONS cohort. During 2009
to 2010, at every 3-month interval, subjects completed computer-assisted
self-interviews detailing risk behavior in the prior 3 months. To assess the
relationship between transmission risk and time, we categorized individuals as
being in the pre-diagnosis, post-diagnosis (as long as 6 months post-diagnosis),
or later follow-up period based on their first interview. We calculated the
mean number of partnerships for each category. Trends over time were assessed in
subsets of individuals with data at multiple time points using linear
Results: In 504 interviews, 237 MSM contributed
data: 52 (10.3%) interviews assessed behavior pre-diagnosis, 65 (12.9%) post-diagnosis,
and 387 (76.8%) in follow-up. The mean number of sexual partners per 3 months
was significantly higher pre-diagnosis (12.2) than post-diagnosis (3.8) and follow-up
(7.5) periods. The proportion of reported partners who were HIV– or
of unknown status was 0.80 pre-diagnosis, 0.24 post-diagnosis, and 0.62 in follow-up.
Mean “risk partnerships” per 3 months was 2.80 pre-diagnosis, but was
significantly lower in both post-diagnosis (0.09) and follow-up (0.20) groups.
The estimated risk reduction associated with being in the follow-up vs pre-diagnosis
group was 93% (p = <0.0001). If partnerships were considered risky
only when a subject was viremic (plasma viral load >500), the mean numbers
of risk partnerships (2.80 in the pre-diagnosis group) were significantly lower
in both post-diagnosis (0.09) and follow-up (0.03) groups, resulting in a 99%
estimated risk reduction between pre-diagnosis and follow-up (p <0.0001).
From 6-month post-diagnosis to 12 years of follow-up, there were no trends to
increase in total or risk partnership rates over time.
Conclusions: Among recently infected individuals
with high-risk sexual behavior at baseline participating in the OPTIONS cohort,
patterns of sexual behavior were consistent with dramatic and sustained
reductions in HIV transmission risk related to adoption of seroadaptive
tactics. Improving early diagnosis of HIV infection would empower MSM to
further decrease their risk of transmitting HIV, a behavior change that is