***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Studies enrolled 37724 North American youth; participants were ethnically diverse. Programs took place in schools (10), community facilities (24), both schools and community facilities (2), healthcare facilities (2), and family homes (1). Median final follow-up occurred 12 months after baseline. Results showed no evidence that abstinence-plus programs can affect self-reported sexually transmitted infection (STI) incidence, and limited evidence that programs can reduce self-reported pregnancy incidence. Results for behavioral outcomes were promising; 23 of 39 evaluations found a significantly protective intervention effect for at least one behavioral outcome. Consistently favorable program effects were found for HIV knowledge. No adverse effects were observed. Several evaluations found that one version of an abstinence-plus program was more effective than another, suggesting that more research into intervention mechanisms is warranted. Methodological strengths included large samples and statistical controls for baseline values. Weaknesses included under-utilization of relevant outcomes, self-report bias, and analyses neglecting attrition and clustered randomization. Many abstinence-plus programs appear to reduce short-term and long-term HIV risk behavior among youth in high-income countries. Evidence for program effects on biological measures is limited. Evaluations consistently show no adverse program effects for any outcomes, including the incidence and frequency of sexual activity. Trials comparing abstinence-only, abstinence-plus, and safer-sex interventions are needed.
Output:

This review included 39 randomized and quasi-randomized controlled trials comparing abstinence-plus programs to various control groups (eg "usual care," no intervention). Although we conducted an extensive international search for trials, all included studies were conducted among youth in the US, Canada, and the Bahamas (total baseline enrolment=37724 participants). The included programs took place in schools, community centers, and healthcare facilities. We did not conduct a meta-analysis because of missing data and variation in program designs. Using various control groups, 24 of 39 evaluations showed a significantly protective intervention effect on at least one biological or behavioral outcome at short-term, medium-term, or long-term follow-up. Eight trials found no evidence that abstinence-plus programs affect self-reported sexually transmitted infection (STI) incidence and limited evidence that programs have a protective effect on self-reported pregnancy incidence. Results for behavioral outcomes were inconsistent across studies. Findings in almost every trial assessing HIV-related knowledge favored the intervention group over controls. No harms were observed for any outcome, including incidence and frequency of sexual activity. Limitations for this review include underreporting of relevant outcomes, reliance on program participants to report their behaviors accurately, and methodological weaknesses in the trials.