HIV, Other STIs, and Teen Pregnancy: Group-Based Comprehensive Risk Reduction Interventions for Adolescents

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Findings and Recommendations

The Community Preventive Services Task Force (CPSTF) recommends group-based comprehensive risk reduction (CRR) interventions delivered to adolescents to promote behaviors that prevent or reduce the risk of pregnancy, HIV, and other sexually transmitted infections (STIs). The recommendation is based on sufficient evidence of effectiveness in:

  • Reducing a number of self-reported risk behaviors, including:
    • Engagement in any sexual activity
    • Frequency of sexual activity
    • Number of partners, and
    • Frequency of unprotected sexual activity
  • Increasing the self-reported use of protection against pregnancy and STIs
  • Reducing the incidence of self-reported or clinically-documented sexually transmitted infections

There is limited direct evidence of effectiveness, however, for reducing pregnancy and HIV.

The full CPSTF Finding and Rationale Statement and supporting documents for HIV, other STIs and Teen Pregnancy: Group-Based Comprehensive Risk Reduction Interventions for Adolescents are available in The Community Guide Collection on CDC Stacks.

Intervention

Comprehensive risk reduction (CRR) interventions promote behaviors that prevent or reduce the risk of pregnancy, HIV, and other sexually transmitted infections (STIs). These interventions may:

  • Suggest a hierarchy of recommended behaviors that identifies abstinence as the best, or preferred method but also provides information about sexual risk reduction strategies
  • Promote abstinence and sexual risk reduction without placing one approach above another
  • Promote sexual risk reduction strategies, primarily or solely

This review evaluated CRR interventions delivered in school or community settings to groups of adolescents (10-19 years old). These interventions may also include other components such as condom distribution and STI testing.

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review of 62 studies with 83 study arms (search period 1988 — August 2007). The systematic review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to preventing HIV, other STIs, and teen pregnancy.

Study Characteristics

Interventions that evaluated STIs were mostly implemented in community settings with adolescents at high-risk for STIs.

Interventions included in this review were:

  • Targeted to adolescents
    • Girls only
    • Boys only
    • Girls and boys together
  • Delivered in group settings in schools or communities
  • Led by adult or peer educators
  • Implemented as single or multicomponent programs
  • Tailored to groups or individuals

Content of these interventions addressed prevention of:

  • HIV and STIs
  • Pregnancy

Summary of Results

Sixty-two studies with 83 study arms qualified for this review.

  • Results from meta-analyses show that effects were favorable and statistically significant for the following outcomes.
    • Sexual activity: decrease of approximately 12% (54 study arms)
    • Frequency of sexual activity: odds ratio (OR) = 0.81, 95% confidence interval (CI) 0.72, 0.90 (14 study arms)
    • Number of partners: decrease of approximately 14% (OR = 0.83, 95% CI 0.74, 0.93; 27 study arms)
    • Unprotected sexual activity: decrease of approximately 25% (OR = 0.70, 95% CI 0.60, 0.82; 28 study arms)
    • STIs: decrease of approximately 31% (OR = 0.65, 95% CI 0.47, 0.90; 8 study arms)
    • Use of protection (including use of condoms, oral contraceptives or both): increase of approximately 13% (OR = 1.39, 95% CI 1.19, 1.62; 50 study arms)
      • Condom use: increase of approximately 12% (OR = 1.45, 95% CI 1.20, 1.74; 44 study arms)
  • Results from meta-analyses were also favorable but statistically nonsignificant for the following outcomes.
    • Oral contraceptives: increase of approximately 22% (OR=1.29, 95% CI 0.89, 1.85; 10 study arms)
    • Dual use (use of both condoms and oral contraceptives): increase of approximately 17% (OR=1.21, 95% CI 0.70, 2.12; 4 study arms)
    • Pregnancy: decrease of approximately 11% (OR=0.88, 95% CI 0.60, 1.30; 11 study arms)
  • The review team also examined consistent condom use, a subgroup of the condom use outcome. The results were in the favorable direction, though statistically nonsignificant.
    • Consistent condom use: OR=1.24, 95% CI 0.96, 1.62 (19 study arms)
  • In 17 of the studies, at least one relevant outcome was reported that could not be included in the meta-analyses because of too little information to calculate an odds ratio. The results for these studies were consistent with the results of the meta-analyses.
  • Interventions may be somewhat more effective for boys than girls.

Summary of Economic Evidence

Ten studies qualified for the economic review, including 8 economic evaluations of individual programs. Monetary values are reported in 2008 U.S. dollars.

  • Program costs ranged from $66 to $10,024 per person per year (6 studies).
    • The wide range in costs is the result of variation in program content, number of participants, program duration, and type of program setting.
    • The highest cost programs tended to be multifaceted youth development interventions.
    • The lowest cost programs were school-based and curriculum-based education or involved a large number of participants.
  • The benefit over cost ratio ranged from 2.7 to 3.7. This means that every dollar invested in the CRR programs yielded between $2.70-$3.70 in returns based on savings in healthcare costs related to pregnancies, HIV, and STIs and improvement in income associated with higher educational attainment (2 cost-benefit studies).
    • A separate cost-benefit study that looked at the most expensive program found that the cost of the program exceeded the economic benefits of pregnancy prevention.
  • The net cost per quality adjusted life year (QALY) ranged from $9,000 to $76,000 (2 cost-utility studies).
  • CRR interventions resulted in healthcare savings from prevented pregnancies and STIs that ranged from $5.80 per participant per year for those aged 13-14 years to $338 per participant per year for those aged 18-19 years (1 dissertation).
    • Avoided pregnancies made up 80% of these savings for those aged 13-14 years and more than 95% for those aged 18-19 years.
  • Only 1 of 7 pregnancy prevention programs was found to be cost saving in the state of Washington. This is based on a review of programs requested by the state legislature.

Applicability

Results suggest that CRR interventions are applicable to:

  • Youth ranging from 10-19 years of age
  • Male only, female only and coed groups
  • Majority African-American, majority White, majority Hispanic and mixed race samples
  • Both virgin and nonvirgin populations
  • School and community settings

Evidence Gaps

Across both reviews, there was no consistent evidence of differential effects on outcomes for any of the 12 critical moderator variables (sex, virginity status, age, race/ethnicity, setting, dosage, focus, deliverer, multicomponent, targeting, study design, and comparison group type). Also, the majority of the studies examined interventions delivered to coed groups and results were not reported by sex. This limits the ability to determine differential effectiveness by sex for comprehensive risk-reduction and abstinence education interventions. This limitation extends to the evaluation of the effectiveness of parental participation as well, since it was an uncommon component in these reviews and often had low participation rates.

More consistent reporting of moderator variables by study authors is needed to clarify which of these (or other characteristics) may maximize the effectiveness of adolescent sexual behavior interventions. In addition, common measures of sexual behavior and standard intervals for follow-up assessments of these outcomes would allow for more comparability across studies and lead to a better determination of the overall public health impact of these interventions.

In terms of economic efficiency, future research is needed to examine how cost benefit or cost-effectiveness estimates vary depending on age, sex, and risk status of participants. For programs with objectives beyond pregnancy and STI prevention, future research needs to evaluate the full impact of such programs from a societal perspective, including non-health outcomes such as improved employment potential, and higher future earnings of program participants. Finally, for school-based programs, additional research needs to address the impact on school resources where the facilities, staff, or time from the school systems may be used for these programs.

Implementation Considerations and Resources

Barriers to intervention implementation can be organized into three categories:

  • Restrictions on intervention activities (e.g., community demands about intervention content)
  • Funding requirements (e.g., federal requirements associated with federal funding)
  • Participation challenges (e.g., low involvement from parents or adolescents, especially in voluntary programs)

Crosswalks

Healthy People 2030 icon Healthy People 2030 includes the following objectives related to this CPSTF recommendation.