Changes in Sex Networks and Repeat STDs among Male Adolescents and Young Adults Jonathan M Ellen 1, Charlotte Gaydos 1, Michelle Chung 1, Nancy Willard 1, Cornelius A Rietmeijer 2 1 Johns Hopkins School of Medicine 2 Denver Public Health Department

Background Individuals with repeat infection are believed to play a greater role in maintaining endemic rates STIs Identification of individuals at increased risk for repeat infection could trigger specific interventions Studies have failed to identify predictors of repeat GC and CT beyond race/ethnicity, age, and geography

Initial vs. Repeat Infection Correlates of initial GC/CT –Condom use –Rate of sex partner turnover –Sex partners’ networks (local networks) Correlates of repeat GC/CT –Changes in correlates of initial STI after initial STI Little evidence that there are changes condom use If current sex partners treated, having a new partner may be protective or risky depending on their network

Sex Networks Prevalence of STI in local sex networks correlated with risk of STI of members Local sex networks vary in their prevalence of STI Individuals may migrate in and out of sex networks Sex networks are closely linked to social networks Could target social networks along with sex networks for control activties

Objectives To determine whether decrease in the percentage of sex partners who are within the index’s social network is associated with decrease risk for repeat GC and/or CT among those with new partners.

Methods Longitudinal research study Asymptomatic CT- and GC-infected boys years old from the non-detention venues in Baltimore City and Denver, CO Participants interviewed and sex contacts notified Re-interviewed and tested for GC/CT at 1 month and 4 months

Participant Interview Asked about each partner including –New partners since last interview –Old partners mentioned at other interviews Queried about their perceptions of their partners drug and sex behaviors and their link to social networks –Egocentric data

Social and Sex Network Overlap Each sex partner was coded as within participants’ social network or not within social network Defined as within network if any: –Met through close friends –More than ½ of friends knew –Friends had sex with partner –Partner knew any of other sex partners Percentage of sex partners within social network Number of Interval Sex Partners in Social Network Number of Total Interval Sex Partners X 100

Analysis Independent variables –New partner since last interview –Change in percentage overlap since last interview Between baseline and 1 month interview Between 1 month and 4 month interview Dependent variable –GC/CT diagnosis at end of interval Logistic regression and GEE Analysis stratified by city

Participants Baltimore N=51 Denver N=100 Mean age18.0 years20.4 years Race/Ethnicity AA Latino White Asian 98% 0% 2% 23% 48% 27% 2% Follow-up visits

Recruitment Venues Baltimore (N=51) Denver (N=100) SBHC51%4% Teen Clinic49%10% STD Clinic38% Drug Treatment2% Street Outreach9% DHD Outreach21% CBO15%

Overall: STD by New Partner (N=209 visits) No STDSTD No New partner125 (66%)8 (42%) New Partner65 (34%)11 (58%) Odds Ratio = 2.83 (1.03,7.80)

Baltimore: STD by New Partner (71 visits) No STDSTD No New partner39 (95%)2 (5%) New Partner25 (83%)5 (17%) Odds Ratio = 3.90 (0.70,21.70)

Denver: STD by New Partner (138 visits) No STDSTD No New partner86 (93%)6 (7%) New Partner40 (87%)6 (13%) Odds Ratio = 2.15 (0.65,7.08)

Baltimore: STD by Change in Overlap (30 visits)* No STDSTD No decrease in overlap12 (71%)5 (29%) Decrease in overlap13 (100%)0 (0%) Odds Ratio = (0.17,0.34) * Among those with a new partner

Denver: STD by Change in Overlap (38 visits)* No STDSTD No decrease in overlap21 (87%)3 (13%) Decrease in overlap12 (86%)2 (14%) Odds Ratio = 1.17 (0.17,7.99) * Among those with a new partner

Limitations Lack of validated definition of social and sex network overlap Relies on perceptions of partners behaviors Small sample size

Conclusion Failure to replicate Baltimore findings in Denver may be due to differences in populations, extent of DIS activity, or limitations of study To the extent that future studied replicate Baltimore findings, preventive treatment of social networks may reduce repeat infection among adolescents and young adults

Funding Centers for Disease Control and Prevention, Division of STD Prevention