Background:  Observing individuals after the diagnosis of recent HIV infection provides information critical to secondary prevention from those highly infectious. We assessed transmission behaviors of men who have sex with men (MSM) with recent HIV infection during their first year post diagnosis. 

Methods:  Behavioral data from 193 recently HIV-infected MSM enrolled from 2002 to 2006 in the Southern California Acute Infection and Early Disease Research Program (AIEDRP) was collected via computer-assisted self-administered interviews, as often as every 3 months for one year. Changes over time in numbers and HIV status of partners, unprotected anal intercourse (UAI), drug use, and partnership dynamics via the Partnership Assessment Scale (PAS) were assessed. A bivariate random-effect logistic regression of UAI with separate but correlated random effects for baseline and follow-up was used to assess the associations with individual and partner characteristics.

Results:  Participants were mostly white (71%) and Hispanic (21%) with a mean age of 35 years and with 88% having some college education. During the first year of follow-up, participants reported on 1,011 total partnerships. The mean numbers of partners reported in the month preceding each interview decreased significantly (from 8.81 to 5.84; P <0.0001); decreasing most from baseline to 3 months (P< 0.0001 (95%CI 22% to 35% drop). Percents reporting UAI with any partner remained stable over the year, but increased among methamphatmine (MA) users. Those reporting UAI with their last HIV uninfected partner decreased from baseline to 6 months (66% to 20%) and then rebounded at 12 months to 79%. In multivariable models for the year following HIV infection, reported UAI was significantly associated with: Hispanic race/ethnicity, Adjusted Odds Ratio (AOR) 0.51, 95%CI 0.32 to 0.81); PAS score at baseline, AOR 1.05 (1.02 to 1.09); PAS during follow-up, AOR 1.06 (1.02 to 1.1); baseline MA use, AOR 3.2 (1.82 to 5.62); MA use during follow-up AOR 5.46, (2.24 to 13.3); HIV negative partner during follow-up, AOR 0.32 (0.18 to 0.59); and partners with unknown HIV status during follow-up, AOR 0.42 (0.21 to 0.84). 

Conclusions:  These MSM with recent HIV infection reported large decreases in risk behavior and increases in sero-sorting soon after diagnosis followed by a rebound after 6 months, potentially identifying critical time points for behavioral interventions targeting newly HIV-infected individuals.