Behavioral Research and STIs Objectives l Discuss how behavior influences the basic reproductive rate of an epidemic l Describe some of the behavioral models l Discuss the concept of Core Group l Discuss Social Network Analysis

Behavioral versus Clinical

Basic Reproductive Rate of Infection

The Reproductive Rate R o > 1 epidemic R o = 1 equilibrium R o < 1 prevalence declines

R o basic reproductive rate l Defines the average number of secondary infections generated by one primary case in a susceptible population of defined density l the host population is divided into compartments: susceptibles, infected (latent), and infectious

(  )Transmission Probability l infected and susceptible l number of partners l types of partners l types of sexual acts l frequency of sexual acts l virulence of infection l duration of infection l when infection occurred l when infection was treated

Sexual Risk Behavior (Aral, 194) l Age at sexual debut l Number of sex partners l Non-discriminating sex partner recruitment l Sexual practices l Frequency of intercourse l Intercourse during menses l Condom use l Vaginal douching l Male circumcision

Behavioral Models of Disease

Trait Concept l Antisocial personality l Chronic self-destructiveness l Erotophobia-erotophilia l Impulsivity l Independence-conformity l Locus of control l Masculinity-femininity l Neuroticism-extraversion-psychoticism

Trait Concept l Risk taking l Self-efficacy l Self-esteem l Self-monitoring l Sensation seeking l Sex guilt l Social desirability

D - the Infectious Period

c- mean rate of sexual partner change l depends on demographic and social factors l magnitudes are correlated with other factors such as number of sex acts, type of sexual contacts and mixing. l Does a Core Group exist?

Core Group

Core Group (Thomas and Tucker, 1996) l Defined as: People who infected a large proportion of the time, infect more than one other person, are repeatedly infected, are prostitutes or their clients, geographic areas with large numbers of cases l Mathematical l Clinical-epidemiologic l sociocultural

Definitions applied to Core Group (Thomas and Tucker, 1996) l Groups whose prevalence of GC is > 20% l Prostitutes l Persons who have many sexual contacts l very sexually active persons who are asymptomatic when infectious l people repeated infected with STD l people with > 5 sex partners l people with clusters of high-risk behavior l adolescent males in detention l census tracts that are responsible for > 50% of cases

Social Network Analysis

Linear Concept of transmission of an STD

Network informed concept of disease transmission

Sexual Behaviors (Aral; 1994) l Early age at sexual debut l Large number of lifetime sexual partners l Large number of current sexual partners l Non-discriminating sex partner recruitment patterns l High risk characteristics of sexual partners l Specific sexual practices l frequency and timing of sexual intercourse l Sexual abuse during childhood

Health Behaviors (Aral; 1994) l Condom and Contraceptive use l Vaginal douching l Male circumcision l Health Care seeking l Compliance with therapy l Compliance with behavioral recommendations

Substance Abuse (Aral; 1994) l Associated with anonymous sex l Associated with exchange for drugs or money l Reduces likelihood that safer sex will be practiced l Includes injectables, inhalables, and alcohol

Transmission Process Shiboski and Padian, JID 1996;174 Partner choice sexual contact population/ group level factors individual/ Partner level factors Transmission