Seattle study was designed to find out whether the sexual risk behaviour
patterns men disclosed in a typical behaviour survey were purposeful – that is, whether they were part of a considered HIV
risk strategy. Between February and August 2013, researchers at the Seattle
HIV/STI clinic asked gay male service users to fill in two separate questionnaires:
one detailing their actual recent sexual risk behaviour (condom use, status of
partners, sex role and so on) and the other asking them what sexual risk
strategies they tried purposefully to use. Eligible men was anyone who was at least 18 years old, who who reported any sex with a man in the past year, and who
of 1902 eligible men, 51% (964) completed both questionnaires, of whom 835
(87%) were HIV negative and 129 (13%) were HIV positive. The questionnaire
asking about chosen strategy asked specifically whether they used one of these
- Strict serosorting, i.e. only having sex, with or
without condoms, with partners of the same HIV status;
- Condom serosorting, i.e. only having condomless sex with partners of the same
status, but allowing sex with condoms with partners of opposite or unknown
- Seropositioning, i.e. having condomless sex with
partners of any HIV status but being the insertive partner (‘top’ if
HIV negative or the receptive partner (‘bottom’) if HIV positive.
per cent of the men (both HIV positive and negative) reported some kind of
seroadaptive behaviour, meaning that their choice of partner or behaviour was
correlated in some way with their partner’s HIV status. Fifty per cent of HIV-negative men and 42% of HIV-positive men (46% on average) reported in the other questionnaire
that this was part of a deliberate strategy. This means that 86% of men who showed
seroadaptive behaviour agreed they were using it as part of a conscious strategy.
researchers do not give details of the behaviour of the other 45% who were not 'sero-adapters' but, if consistent with other
surveys, this would be a mix of men who did not have anal
sex, men who maintained 100% condom use with all partners, and men who appeared
to have no risk-avoidance strategy.
serosorting was by far the most popular strategy of the three options listed by
the researchers. The respective figures for those who were strict serosorters,
condom serosorters, or 'seropositioners' were 42% of HIV-negative respondents for strict serosorting (with 39%
saying it was their chosen strategy), 6.5% for condom serosorters (5.2% saying
it was their strategy), and 7.1% using seropositioning (with 6.5% saying it was
their chosen strategy).
serosorting was less popular with HIV-positive men, with 32% doing it as behaviour and 25% as strategy, while the other two
behaviours were more popular than in HIV-negative men, at 11% for condom serosorting and 10% for seropositioning.
means that for 42% of HIV-negative and 33% of HIV-positive men, their main
strategy for keeping themselves safe was to to restrict sex to people they knew or presumed to be of the same HIV status, or avoid sex with people who they knew to be of
the opposite HIV status. This strategy was systematic and
planned by 39% and 26% of them respectively. Strict serosorting was practised
by 75% of HIV-negative men and 60% of HIV-positive men who had any
is overwhelmingly the most common seroadaptive behavior in our clinic,” comment