AIDS Behav (2009) 13:1054–1060 the one hand, this time period presents special challenges: people are coping with a new diagnosis, including the chal- lenge of obtaining needed medical care. They also may be experiencing illnesses associated with seroconversion. And, they may still face many of the same circumstances and factors that contributed to the risk behaviors that led to infection. On the other hand, previous research suggests that people can reduce transmission risks after testing HIV- positive (Colfax et al. 2002; DiFranceisco et al. 2005; Gor- bach et al. 2006; Weinhardt et al. 1999). Understanding the degree to which people adjust sexual behaviors after diag- nosis with acute/early HIV in particular—and examining how exactly they accomplish this goal and their motivations for doing so—is valuable for developing AHI risk reduction interventions. Such programs will need to build upon behavior changes prompted by initial diagnosis and offer support for longer-term risk reduction efforts. This is the third in a series of ﬁve papers (see also Atkinson et al. 2009; Kelly et al. 2009; Kerndt et al. 2009; Remien et al. 2009) that describe results from the National Institute of Mental Health Multisite Acute HIV Infection Study (see Kerndt et al. 2009, for the overall aims of the study). In the analyses presented here, we examine changes in sexual risk behaviors, seeking speciﬁcally to understand the degree to which such changes are a product of reduc- tions in partners, reductions in sex acts, increases in con- dom use, and use of serosorting and seropositioning. The latter two approaches are informal risk reduction tech- niques. With serosorting, individuals choose partners thought to have a similar HIV serostatus (Suarez and Miller 2001; Suarez et al. 2001). Recent studies have documented its increasingly widespread adoption, particularly among men who have sex with men (MSM) (Grov et al. 2007; Mao et al. 2006; Osmond et al. 2007; Parsons et al. 2005; Truong et al. 2006). With seropositioning, HIV serodis- cordant male couples choose sexual positions in which the likelihood of HIV transmission is believed to be lower (e.g., the HIV-positive partner will be the receptive, as opposed to insertive, partner during anal sex) (Parsons et al. 2005; Van de Ven et al. 2002). Informal risk-reduc- tion techniques can in theory reduce the likelihood of HIV transmission, but require accurate health information and thorough disclosure to be successful. Inaccurate serostatus disclosures prior to serosorting have already been shown to lead to increased disease transmission events (Butler and Smith 2007). Methods Participants were 18 years of age or older, had sufﬁcient English proﬁciency to complete the study measures, and had documented evidence of acute or early HIV infection 1055 (see Kerndt et al. 2009). Participants were asked to attend two study visits: the ﬁrst slated for within 4 weeks of when the participant learned of his or her diagnosis (T1) and a second slated for 8 weeks later (T2). At each visit, par- ticipants completed an in-depth qualitative interview and a structured quantitative survey (see Remien et al. 2009). In the structured surveys, participants provided detailed information on their recent sexual history. Speciﬁcally, during their T1 interview, they were asked to describe their sexual behaviors in the 8 weeks before diagnosis and, sep- arately, their behaviors in the days or weeks that had elapsed between diagnosis and the day of the interview (M = 5.6 weeks; SD = 3.0 weeks). At their T2 interview, they described their behaviors in the weeks that had elapsed between the T1 and T2 interviews (M = 9.9 weeks; SD = 2.5 weeks). Interviewers used a visual schematic to help participants remember start and end dates for these recall periods. For each assessed time period, participants provided separate counts of the number of HIV-positive, HIV-nega- tive, and HIV-serounknown (i.e., unknown to the partici- pant) partners with whom they had had oral, vaginal, and/or anal sex. Then, for each partner type, they provided counts of the number of times they had engaged in oral, vaginal, and anal sex. (As applicable, the assessments separately captured insertive and receptive acts.) If vaginal or anal sex acts were reported, participants also provided counts of the number of times that condoms were used. During the in-depth qualita- tive interviews, participants were asked to focus on two narratives of importance to behavior change analyses: their social and sexual lives before becoming infected with HIV, and their social, sexual, and preventive behaviors following diagnosis. Analyses For quantitative analyses, we calculated the total number of partners (stratiﬁed by serostatus), and the total number of vaginal and anal sex acts (stratiﬁed both by condom use and partner serostatus). Oral sex was not included in the analyses. Because the recall periods differed in length, we standardized the counts by dividing the number of partners and risk acts reported for each participant by the number of weeks that had elapsed in a recall period for that partici- pant. For example, an individual who reported eight risk acts in an eight-week period would have a standardized count of one act/week. We then used paired-samples t-tests to assess the signiﬁcance in changes across recall periods in the mean number of partners and mean number of sex acts, and chi-square analyses to examine changes in the relative distribution of partners and sex acts across partner sero- status and condom use strata. For qualitative analyses, we coded and then sorted data following procedures described elsewhere (Remien et al. 123