Assessing the role of school-based sex education in sexual health behaviours: a systematic review

Figures & data

Figure 1. PRISMA flow diagram depicts study identification via databases.

A flow chart showing the flow of information through the different stages of a systematic review.

Table 1. Characteristics of studies included in the review.

Study/Country/Quality Rating	Sample characteristics	Intervention characteristics	Sexual health behaviour outcomes	Length of follow up & Results	Effective Y/N
1. Menna et al. (2015)Design: Quasi-experimental Country: Ethiopia Quality: Moderate	Students/Adolescents (Grade 11) No mean age reported Age range 15 to 18 Pre-test intervention group: (n = 240, 85.7%); Pre-test control group: (n = 234, 83.6%) Post-test intervention group (n = 232, 82.9%); Post-test control group (n = 223, 79.6%)	Setting: Secondary school, Group level, face to face, classroom setting Duration: 2 sessions per week, 40 mins for both intervention and control Delivery agent: Peer educators Intervention: No information reported; Control: No information reported.	Target behaviour(s): Consistent condom usage in previous 12 months	Time points: Baseline and 3 months (End of Intervention) and 3 months (follow up) Length of follow up: Short-term <12 months	Yes
2. Musiimenta (2012) Design: Controlled pre & post test Country: Uganda Quality: Moderate	Secondary school students, all years recruited No mean age reported Age range 11 – 16 years Pre-test (N = 300) Intervention group (n = 152); Control group (n = 148) Post-test (N = 292) Intervention. Group (n = 146); Control group (n = 146)	Setting: Secondary school, Group level, face to face, classroom setting Duration: 14 lessons, no time allocation reported Delivery agent: Teachers Intervention: World Starts With Me, sexuality and HIV/AIDS intervention; Control: Not reported	Target behaviour(s): Abstinence, Number of sexual partners, Condom use	Timepoints: Baseline and 10 months (End of intervention) Length of follow up: Short-term <12 months	Yes
3. Berglas et al. (2016)Design: cRCT Country: USA Quality: Moderate	High school students, Grade 9 M age 14.2 (SD = 0.62) No age range reported N = 972 Intervention group (n = 412); Control group (n = 329)	Setting: High school, Group level, face to face, classroom setting Duration: 12 sessions, during regular class times Delivery agent: Health educators Intervention: The Sexuality Education Initiative intervention.Control: Received sexual health services and the control classroom curriculum.	Target behaviour(s): Primary outcomes: i) Pregnancy risk, ii) STI risk, iii) Multiple sexual partners, iv) Ever using sexual health services Secondary outcomes: (1) Ever engaging in vaginal or anal sex, (2) Ever engaging in oral sex, (3) Engaging in vaginal or anal sex in the previous 3 months, (4) Engaging in oral sex in the previous 3 months, (5) Using a condom at last vaginal or anal sex, (6) Using birth control or condoms at last vaginal or anal sex, and (7) Currently carrying a condom (e.g. in a pocket)	Timepoints: Baseline, intervention and 12 months follow up Length of follow up: Long-term: ≥12 months Results: Condom use effect size OR = 2.71, 95% CI = 1.44 – 5.09	Yes
4. Denny and Young (2006) Design: Quasi-experimental Country: USA Quality: Weak	High school students, Grades 9 or above No mean age and age range reported Pre-test: Treatment group (n = 226); Control group (n = 111) Post-test: Treatment group (n = 195); Control group (n = 92) 18 month follow up: Treatment group (n = 168); Control group (n = 76)	Setting: High school, group level, face to face, classroom setting Duration: 5 weeks, 24 sessions, no time allocation reported Delivery agent: Teachers (with 3.5 hours training provided) Intervention: Sex can wait curriculum; Control: Schools had existing sexuality education programmes.	Target behaviour(s): Yes/No items asking whether students had ever participated in sexual intercourse and whether they had done so in the last 30 days.	Timepoints: Baseline, 5 weeks (End of Intervention) and 18 months follow up Length of follow up: Long-term: ≥12 months	Yes
5. Esere (2008) Design: Quasi- experimental Country: Nigeria Quality: Moderate	Secondary school students, all school years recruited M age = 15.5 Age range 13–19 years Treatment Group A: Male (n = 6) & Female (n = 6) Control Group B: Male (n = 7) & Female (n = 5)	Setting: Secondary school, group level, face to face, classroom setting Duration: Eight sessions intensity, one session per week, no time allocation reported Delivery agent: Researcher of project Intervention: Sex Education Programme; Control: No treatment provided	Target behaviour(s): Self-reported exposure to 1) sexually transmitted diseases, 2) multiple sex partners, 3) anal sex, 4) oral sex, 5) non-use of condom. (Cronbach’s 0.73).	Timepoints: Baseline, 8 weeks (End of Intervention) Length of follow up: Not reported	Yes
6. Li et al. (2011) Design: Quasi-experimental Country: China Quality: Moderate	High school students, all school years recruited (M = 16.3, SD = 0.66) Age range 15–19 years Total sample: N = 304 students. Baseline: Intervention group (n = 140); Control group (n = 164) Follow up: Intervention group (n = 131); Control group (n = 156) 94.4% of the baseline cohort participated in the 6-month post-intervention survey (N = 287).	Setting: High school, Group level, face to face, classroom setting Duration: 8 session, delivery time of 12 hours (90 minutes per session) Delivery agent: Mix delivery agent - Four graduate students and seven faculty members from University in Nanjing Intervention: Cultural adaptation of the FOK HIV prevention programme.Control: Not reported	Target behaviour(s): Sexual intercourse in the past 6 months	Timepoints: Baseline and 6 months follow up Length of follow up: Short-term <12 months	No
7. Thato et al. (2008) Design: Quasi-experimental Country: Bangkok Quality: Moderate	High school students, Grades 9, 10, 11 Intervention group M age = 15.67; Control group M age = 15.93 Age range 13–18 years Total sample (N = 552) 3 month follow up: Intervention group (n = 230); Control group (n = 261) 6 month follow up: Intervention group (n = 230); Control group (n = 189)	Setting: High school, Group level Face to face sessions, classroom setting Duration: 6 weeks, one-hour modules (5 module total), divided equally into two consecutive 3-hour classes taught weekly by the first author Delivery agent: Researcher of project Intervention: CSCSEP Curriculum.Control: Not reported	Target behaviour(s): Condom use among sexually active and consistent condom use and frequency of sexual activity.	Timepoints: Baseline, 6 weeks (End of Intervention) and 3, 6 month follow up Length of follow up: Short-term <12 months Results: Frequency of sexual activity effect size OR 0.80, 95% CI = 0.84 – 0.95	Yes
8. Burnett et al. (2011)Design: RCT Country: Swaziland Quality: Moderate	High school students, Grades 9 & 11 No mean age and age range reported N = 204 (101 males and 103 females) 66.5% completed surveys at pre and post-test (N = 135).	Setting: High school, group level, face to face, workshop setting Duration: 13 (weeks) half-day Saturday sessions, with 1 hour per module (4 modules per week) (4 hours total each week) Delivery agent: Health educators Intervention: It’s Our Future Too! Intervention. Control: Not reported	Target behaviour(s): 1) Ever had sex 2) Condom use at last sex	Timepoints: Baseline and 13 weeks (End of Intervention) Length of follow up: Short-term <12 months	No
9. LaChausse (2006) Design: Longitudinal experimental design Country: USA Quality: Moderate	High school students, Grade 9 No mean age or age range reported Pre-test: Intervention group (n = 216); Control group (n = 137) 6 month follow up: Intervention group (n = 174); Control group (n = 113)	Setting: High school setting, group level, face to face, classroom setting Duration: Six sessions, 45 minutes time allocation Delivery agent: Teachers Intervention: The Positive Prevention HIV/STD Curriculum.Control: Not reported	Target behaviour(s): Frequency of sexual behaviours, condom use, initiation of sexual intercourse	Timepoints: Baseline, 1 month and 6 month follow up Length of follow up: Short-term <12 months	Yes
10. Walker et al. (2006)Design: cRCT Country: Mexico Quality: Moderate	High school students, 1st year from 40 public high schools No age range reported N = 10,954 Post Intervention group (n = 9372) N = 7308 One year follow up (June 2003) Condom promotion group: Females (M age = 16.8) Males (M age = 16.9) Condom promotion group with emergency contraception: Females (M = 16.7) Males (M = 16.9) Control group: Females (M age = 16.7) Males (M age = 16.8)	Setting: High school, group level, face to face, classroom setting Duration: 15 weeks consisting of 30 hours and the contraception arm received two extra hours over 15 weeks resulting in a total of 32 hours Delivery agent: Teachers Intervention: HIV prevention course that promoted condom use and emergency contraceptionControl: Standardised sex education course implemented by the Ministry of Education.	Target behaviour(s): Primary outcome measure was reported condom use.	Timepoints: Baseline, 15 weeks (end of intervention), 12 and 16 month follow up Length of follow up: Long-term: ≥12 months	No
11. Daley et al. (2019)Design: Pair Matched cRCT Country: USA Quality: Moderate	High school students, 9^th grade, No mean age reported Age range 14–16 yrs. Total sample N = 4,789 Intervention group (n = 2,198); Control group (n = 2,590)	Setting: High school, group level, face to face, classroom setting Duration: 25 weekly sessions (over 9 months; 20 hours total) Delivery agent: Health educators Intervention: TOP Level 2 curriculum Control: Standard school sexual health curriculum.	Target behaviour(s): 1) Ever had sex (ever sex), 2) Ever having been pregnant or caused a pregnancy (ever pregnant), 3) Sexual intercourse in the past 3 months (recent sex), & 4) Condom use in the past 3 months (recent condom use).	Timepoints: Baseline, 12 months follow up Length of follow up: Long-term: ≥12 months	No
12. Tucker et al. (2007) Design: Cross sectional before & after Country: Scotland Quality: Moderate	Secondary school students, Year 3 and Year 4 Median age 14 years and 6 months. No age range reported Breakdown of sample not reported	Setting: Secondary schools, group level, face to face, classroom setting Duration: 20 sessions total across 2 school years (10 sessions in 3rd year and 10 sessions in 4th year) and time allocation not specified Delivery agent: Nurses Intervention: Healthy Respect’s Sexual Health And Relationships Education (SHARE). Control: Standard sexual health education programme	Target behaviour(s): Self-reported sexual intercourse at age <16 years.	Timepoints: Not reported Length of follow up: Not reported	No
13. Mwale and Muula (2019)Design: Quasi-experimental Country: Northern Malawi Quality: Moderate	Secondary school students, all years recruited. Intervention group (M age = 16.2); Control group (M age = 16.1) No age range reported N = 360 (Intervention group (n = 158); Control group (n = 202)).	Setting: Secondary school, group level, face to face, classroom setting Duration: 5 sessions over 3 months. No time allocation reported Delivery agent: 6 peer educators trained to facilitate and allowed to practice their roles before the intervention was implemented. Intervention: Peer education risk reduction intervention Control: Standard-as-usual Life skills regimen already provided to adolescents and young people in schools.	Target behaviour(s): Primary outcome: HIV risk reduction Secondary outcomes: Abstinence, Delayed debut, Reductions in unprotected sex, Correct and consistent condom use, Faithfulness to one partner, Reductions in multiple partnerships.	Timepoints: Baseline, 3 months (End of Intervention), 8 month follow up Length of follow up: Short-term <12 months Results: Frequency of sex effect size OR = 0.04, 95%, CI = 0.01–0.20Condom use effect size OR = 0.02; 95%, CI = 0.01–0 .04 Number of sexual partners effect size OR = 0.04, 95%, CI = 0.02–0.11	Yes
14. James et al. (2006)Design: Pre-test and post-test experimental control Country: South Africa Quality: Moderate	Secondary school students, two 9^th grade classes M age = 15.5 Age range 12 – 21 years Total sample: N = 1141 Baseline: N = 844. 6 month follow up (dropout rate 26%) and 4 month follow up: (N = 768)	Setting: Secondary school, group level, face to face, classroom setting Duration: 20-week duration. No time reported Delivery agent: Teachers Intervention: Life Skills Programme focusing on HIV and AIDS prevention. Control: Received odd lessons about aspects of HIV and AIDS education in a nonstructured format and in some cases celebrated awareness days on the topic.	Target behaviour(s): Self-report 1) whether they were ever sexually active (0 = no, 1 = yes), 2) sexually active in the recall period (6 months at T1 and T2, 3 months at T3), and 3) whether they used a condom the last time they had sex (0 = no, 1 = yes; only measured at T2 and T3).	Timepoints: Baseline, 20 weeks (End of Intervention), 6 and 10 month follow up Length of follow up: Short-term <12 months Results: Frequency of sexual activity effect sizes (B = –.05, SE = .26, Wald (1, 657) = 0.03, p = .86, OR = 1.04)Condom use effect sizes (B = –.21, SE = .41, Wald (1, 157) =0.27,p= .60,OR=.81).	No
15. Mba et al. (2007)Design: Pre and post intervention Country: Nigeria Quality: Weak	Secondary school students, all school years recruited M age = 14.3 years Age range 10 – 20 years Total sample: N = 360	Setting: Secondary school, group level, face to face, classroom setting Duration: 6 weeks, 3 hours Delivery agent: Not specified Intervention: Sexually transmitted diseases, HIV/AIDS and family planning intervention Control: Received no programme	Target behaviour(s): Sexual behaviour	Timepoints: Baseline, 6 weeks (End of Intervention) Length of follow up: Short-term <12 months	No
16. Gelfond et al. (2016)Design: Secondary analysis 3-year quasi experimental study Country: USA Quality: Weak	High school students, grades 9, 10 & 11 No mean age or age range reported Baseline: N = 1437 (Intervention group (n = 747); Control group (n = 690)). Before matching: N = 1113 students (Intervention group (n = 578); Control group (n = 535)). Matched: N = 964 (Intervention group: (n = 482); Control group: (n = 482)).	Setting: High school, group level, face to face, classroom setting Duration: Intervention consisted of 16 sessions, over three years (Autumn 2012–Spring 2015) and 25 minutes per session Delivery agent: Health educator Intervention: Need to Know (N2K), intervention Control: Received no programme	Target behaviour(s): Primary outcome: Pregnancy rate within the first 3 years of high school measured with Yes/No response items by 1) Pregnancy event, 2) Sex in past 3 months, 3) Sex in past 3 months without condom and 4) Sex in past 3 months without birth control.	Timepoints: Baseline, 4 years (End of Intervention) Length of follow up: Long-term: ≥12 months	No
17. Mason-Jones et al. (2013) Design: cRCT Country: South Africa Quality: Weak	High school students, Grade 10 No mean age or age range reported Total sample: N = 728 (Intervention group (n = 295); Control group (n = 433)).	Setting: High school, group level, face to face, classroom setting Duration: Not reported Delivery agent: Peer educators Intervention: Peer educators’ intervention on sexual health behavioursControl: Received no programme	Target behaviour(s): Primary outcomes were age of sexual debut and for those who were sexually active and use of a condom at last sex.	Timepoints:Baseline, 18 month follow up Length of follow up: Long-term: ≥12 months Results: Age of sexual debut effect size, adjusted Odds Ratio, 0.17, 95%, CI = −0.20 – 0.55Condom use effect size, adjusted Odds Ratio, 1.19, 95%, CI = 0.56 - 2.52	No
18. Lan et al. (2019)Design: Pre & post test Country: USA Quality: Weak	High school students, 9^th grade No mean age or age range reported Total sample: N = 300	Setting: High school, group level, face to face, classroom setting Duration: 60-minute sessions delivered over 8 weeks Delivery agent: Health educators Intervention: AMP live intervention. Control: Virtual intervention	Target behaviour(s): 1) whether they had ever had sexual intercourse, 2) whether they or their partner had used a condom at their last sexual intercourse.	Timepoints: Baseline, 8 week (End of Intervention) and 3 week follow up Length of follow up: Short-term <12 months	No
19. Cartagena et al. (2006) Design: Survey of 3-year intervention Country: Mongolia Quality: Weak	High school students, grade 10 No mean age reported Age range 15 to 19 Total sample: N = 647 (Intervention (n = 320); Control group (n = 327)).	Setting: High school, group level, face to face, classroom setting Duration: Not specified Delivery agent: Peer educators, trained for 3 days Intervention: Peer education prevention programme. Control: Not specified	Target behaviour(s): Sexual health practices - Condom use during the last three months of sexual intercourse.	Timepoints: Not reported Length of follow up: Not reported	No
20. Rohrbach et al. (2015) Design: cRCT Country: USA Quality: Moderate	High school students, 9^th grade Intervention M age = 14.15 (SD = .60); Control M age = 14.16 (SD =.55) Age range 12–18 years Total sample: N = 1447 (Intervention group (n = 769); Control group (n = 678)).	Setting: High school, group level, face to face, classroom settings Duration: Intervention: 53 days (12 sessions). No time reported; Control: Average span of 9 days Delivery agent: Volunteers (1 day training) Intervention: The SEI curriculum Control: Basic sex education control curriculum.	Target behaviour(s): Primary outcomes: 1) Pregnancy risk, 2) STI risk, 3) Multiple sexual partners, and 4) Use of sexual health services. Secondary outcomes: (1) Ever engaging in vaginal or anal sex; (2) Ever engaging in oral sex; (3) Engaging in vaginal or anal sex in the previous 3 months; (4) Engaging in oral sex in the previous 3 months; (5) Using a condom at last vaginal or anal sex; (6) Using birth control or condoms at last vaginal or anal sex; and (7) Currently carrying a condom	Timepoints: Baseline, 53 days (End of Intervention) and 12 month follow up Control, 9 days (No follow up) Length of follow up: Long-term: ≥12 months Results: Condom use effect size, Odds ratio, 1.97; 95% confidence interval, 1.39 - 2.80Frequency of sexual activity effect size, Odds ratio, 1.13; 95% CI, .82 - 1.56	Yes
21. Taylor et al. (2014) Design: RCT Country: South Africa Quality: Moderate	High school students, Grade 8 Mean age: Males (M = 14.6, SD= 1.4); Females (M = 13.9, SD = 1.1) No age range reported Total sample: N = 818 (Intervention group (n = 432); Control group (n = 386)). 8 month follow up: (Intervention group (n = 383); Control group (n = 298)).	Setting: High school, group level, face to face, classroom setting Duration: 12 weeks, no time reported Delivery agent: Researcher of project Intervention: School life skills programme.Control: Regular sexual health education established in school	Target behaviour(s): 1) ‘Have you ever had sex? 2) Do you use condoms? 3) Have you ever been pregnant/caused a pregnancy?’ (yes/no response) Condom use consistency ‘How often do you use condoms with your regular partner?’ (Four-point Likert response: 1 (never) - 4 (always)).	Timepoints: Baseline, 12 weeks (End of Intervention) and 4 and 8 months follow up Length of follow up: Short-term <12 months	Yes
22. Lohan et al. (2018)Design: cRCT Country: Northern Ireland Quality: Moderate	Secondary school students, no years reported M age = 14 No age range reported Total sample: N = 831	Setting: Secondary School, group level, face to face, classroom setting Duration: 12 months, no time reported Delivery agent: Teacher Intervention: If I Were Jack intervention. Control: Usual school-based sex education programme	Target behaviour(s): Unprotected sex	Timepoints: 12 months (End of Intervention), 9 month follow up Length of follow up: Short-term <12 months Results: Effect size (95% CI 0.5 to 2.2%)	Yes
23. Markham et al. (2014) Design: RCT Country: USA Quality: Moderate	Middle school students, 7^th grade M age = 12.6 No age range reported Follow up surveys completed by N = 1,233 (29.2% attrition), 10^th grade students Excluded 46 students leaving sample of N = 1,187	Setting: Middle school, group level, face to face, classroom setting Duration: 24 sessions (12 in 7th grade & 12 in 8th grade), 50 minutes duration Delivery agent: Researcher of project Intervention: It’s Your Game. Keep It Real (IYG), Risk Avoidance and Risk Reduction programmes. Control: Regular sexual health education established in school	Target behaviour(s): Primary outcome: Delayed sexual initiation by 10th grade Secondary outcomes: 1) unprotected sex at last vaginal intercourse, 2) number of lifetime sexual partners, and 3) other recent (i.e. in the past 3 months) behaviours including frequency of oral, vaginal, and anal sex, 4) frequency of vaginal or anal sex without a condom and 5) number of sexual partners.	Timepoints: Not reported Length of follow up: Not reported Results: Initiation of sex effect sizes Risk Avoidance: adjusted odds ratio [AOR], .64, 95% confidence interval [CI], .42 −.99 Risk Reduction: AOR, .65, 95% CI, .50 - 84	Yes
24. Markham et al. (2012) Design: RCT Country: USA Quality: Moderate	Middle school African American and Hispanic students, 7^th grade Mean age = 12.6 (59.8% Female) No age range reported Total sample: N = 1,258	Setting: Middle school, group and individual level, face to face, classroom setting Duration: 24 lessons, duration of 50-minutes, with 12 lessons in 7th grade and 12 lessons in 8th grade. Delivery agent: Researcher of project Intervention: It’s your game (IYG), keep it real intervention.Control: Regular sexual health education established in school.	Target behaviour(s): Primary outcome: Delayed sexual initiation (oral, vaginal, or anal). Secondary outcome included 1) delayed initiation of oral, vaginal, and anal sex, and on 2) reduced sexual risk behaviour in 9th grade Secondary outcomes: (1) unprotected sex at last vaginal intercourse; (2) frequency of oral, vaginal, and anal sex in the past 3 months; (3) frequency of vaginal or anal sex without a condom in the past 3 months; (4) number of lifetime sexual partners; and (5) number of sexual partners in the past 3 months.	Timepoints: Not reported Length of follow up: Not reported Results: Adjusted odds ratio (AOR) .65, 95% CI = .54-.77	Yes
25. Rohrbach et al. (2019) Design: Quasi-experimental Country: USA Quality: Moderate	Middle school students, Grades 7 and 8 No mean age or age range reported	Setting: Middle school, group level, face to face, classroom setting Duration: 7th grade (18 sessions) 8th grade (6 sessions), no time reported Delivery agent: Teachers Intervention: HIV/STI/teen pregnancy prevention curriculum.Control: No intervention	Target behaviour(s): Primary outcomes: 1) ever engaged in oral sex (performed or received), 2) vaginal intercourse, or 3) anal intercourse (yes/no response) Secondary outcomes: Recent sexual behaviours: 1) ever engaged in oral, vaginal, or anal sex in the past 3 months (yes/no response) 2) condom use at last vaginal or anal sex (two items; yes/no) and 3) whether the subject had vaginal or anal sex with- out the use of condoms in the past 3 months (yes/no response).	Timepoints: Not reported Length of follow up: Not reported	Yes
26. Tortolero et al. (2010) Design: RCT Country: USA Quality: Moderate	Middle school students, 7^th grade students followed through to 9^th grade No mean age and age range reported Total sample: N = 907	Setting: Middle school, group level, face to face, classroom setting Duration: 24 sessions (12 in 7th grade & 12 in 8th grade), 45 minutes duration Delivery agent: Teachers Intervention: IYG intervention. Control: No IYG intervention	Target behaviour(s): Primary outcome: Delayed sexual initiation at 9th grade follow up Secondary outcomes: 1) delayed initiation of specific types of sex (oral, vaginal, anal); 2) delayed sexual initiation by gender and racial/ethnicity; and 3) reduced risk behaviour at the ninth-grade follow-up for those who reported being sexually active in the last 3 months.	Timepoints: Baseline, 24 month follow up Length of follow up: Long-term: ≥12 months	Yes
27. Peskin et al. (2015) Design: RCT Country: USA Quality: Moderate	Middle school students, 8^th grade into 9^th grade No mean age or age range reported Total sample: N = 1,374 Students received a $10 incentive when they completed the 1 year follow up survey	Setting: Middle school, individual level, computer based, classroom setting Duration: 13 sessions, 35–45 minutes Delivery agent: Teachers Intervention: IYG curriculum to simulate student skills practice in real-world situations.Control: No IYG	Target behaviour(s): Primary outcome: Delayed sexual initiation Secondary outcomes: 1) delayed initiation of specific types of sexual activity; 2) number of lifetime sexual partners; 3) current sexual activity (defined as sexual activity in the past 3 months); 4) number of occasions students had sex without a condom; 5) number of partners in the past 3 months; 6) number of partners without a condom in the past 3 months; and 7) use of a condom during last sex.	Timepoints: Baseline, 12 month follow up Length of follow up: Long-term: ≥12 months	No

Table 2. The commonly used Behaviour Change Techniques and examples from interventions.

BCT	Cluster	Description	Example of coded text
4.1 Instruction on how to perform a behaviour (6) 9%	Shaping knowledge	Advise or agree on how to perform the behaviour (includes ‘Skills training’)	‘All eighth graders received computerized skill-based activities practicing steps for correct condom use’
5.1 Information about health consequences (11) 17%	Natural consequences	Provide information (e.g. written, verbal, visual) about health consequences of performing the behaviour	‘Curriculum included modules with information on HIV and Sexually Transmitted Infection Basics; Prevention, Treatment, and Testing of HIV’
5.3. Information about social and environmental consequences (10) 16%	Natural consequences	Provide information about social and environmental consequences of performing the behaviour	‘Curriculum included modules with information on stigma and discrimination; and Living with HIV’
6.1 Demonstration of the behaviour (10) 16%	Comparison of behaviour	Provide an observable sample of the performance of the behaviour, directly in person or indirectly e.g. via film, pictures, for the person to aspire to or imitate (includes ‘Modelling’)	‘The peers are encouraged to: observe and imitate the behaviours of their peer educators and of others’
8.1 Behavioural practice/rehearsal (10) 16%	Repetition and substitution	Prompt practice or rehearsal of the performance of the behaviour one or more times in a context or at a time when the performance may not be necessary, in order to increase habit and skill	‘Role playing, were used to help students to build confidence to negotiate delay of sexual initiation, condoms use, asking a partner’s HIV status, and getting an HIV test done’
9.1 Credible source (15) 24%	Comparison of outcomes	Present verbal or visual communication from a credible source in favour of or against the behaviour	‘Having a doctor present in the lessons helped in giving accurate information about medical issues but the researcher controlled the process of delivery’.

Menna, T., Ali, A., & Worku, A. (2015). Effects of peer education intervention on HIV/AIDS related sexual behaviors of secondary school students in Addis Ababa, Ethiopia: a quasi-experimental study. Reproductive Health, 12(1), 84. https://doi.org/10.1186/s12978-015-0077-9

 PubMedGoogle Scholar

Musiimenta, A. (2012). A controlled pre-post evaluation of a computer-based HIV/AIDS education on students’ sexual behaviors, knowledge and attitudes. Online Journal of Public Health Informatics, 4(1)

 Google Scholar

Berglas, N. F., Jerman, P., Rohrbach, L. A., Angulo-Olaiz, F., Chou, C.-P., & Constantine, N. A. (2016). An implementation and outcome evaluation of a multicomponent sexuality education programme for high school students. Sex Education, 16(5), 549–567. https://doi.org/10.1080/14681811.2015.1133408

 Web of Science ®Google Scholar

Denny, G., & Young, M. (2006). An evaluation of an abstinence-only sex education curriculum: an 18-month follow-up. The Journal of School Health, 76(8), 414–422. https://doi.org/10.1111/j.1746-1561.2006.00135.x

 PubMed Web of Science ®Google Scholar

Esere, M. O. (2008). Effect of sex education programme on at-risk sexual behaviour of school-going adolescents in Ilorin, Nigeria. African Health Sciences, 8(2), 120–125.

 PubMed Web of Science ®Google Scholar

Li, X., Zhang, L., Mao, R., Zhao, Q., & Stanton, B. (2011). Effect of social cognitive theory-based HIV education prevention program among high school students in Nanjing, China. Health Education Research, 26(3), 419–431. https://doi.org/10.1093/her/cyr001

 PubMed Web of Science ®Google Scholar

Thato, R., Jenkins, R. A., & Dusitsin, N. (2008). Effects of the culturally-sensitive comprehensive sex education programme among Thai secondary school students. Journal of Advanced Nursing, 62(4), 457–469. https://doi.org/10.1111/j.1365-2648.2008.04609.x

 PubMed Web of Science ®Google Scholar

Burnett, S. M., Weaver, M. R., Mody-Pan, P. N., Thomas, L. A. R., & Mar, C. M. (2011). Evaluation of an intervention to increase human immunodeficiency virus testing among youth in Manzini, Swaziland: a randomized control trial. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 48(5), 507–513. https://doi.org/10.1016/j.jadohealth.2010.08.015

 PubMed Web of Science ®Google Scholar

LaChausse, R. G. (2006). Evaluation of the positive prevention HIV/STD curriculum. American Journal of Health Education, 37(4), 203–209. https://doi.org/10.1080/19325037.2006.10598904

 Google Scholar

Walker, D., Gutierrez, J. P., Torres, P., & Bertozzi, S. M. (2006). HIV prevention in Mexican schools: prospective randomised evaluation of intervention. BMJ, 332(7551), 1189–1194. https://doi.org/10.1136/bmj.38796.457407.80

 PubMedGoogle Scholar

Daley, E. M., Marhefka, S. L., Wang, W., Noble, C. A., Mahony, H., Arzola, S., Singleton, A., Malmi, M., Ziemba, R., Turner, D., Marwah, E., & Walsh-Buhi, E. R. (2019). Longitudinal evaluation of the Teen Outreach Programme: Impacts of a health promotion programme on risky sexual behaviours. Health Education Journal, 78(8), 916–930. https://doi.org/10.1177/0017896919857777

 Web of Science ®Google Scholar

Tucker, J. S., Fitzmaurice, A. E., Imamura, M., Penfold, S., Penney, G. C., Teijlingen, E. v., Shucksmith, J., & Philip, K. L. (2007). The effect of the national demonstration project Healthy Respect on teenage sexual health behaviour. European Journal of Public Health, 17(1), 33–41. https://doi.org/10.1093/eurpub/ckl044

 PubMed Web of Science ®Google Scholar

Mwale, M., & Muula, A. S. (2019). The efficacy of peer education in sexual behavioral change among school-going adolescents in Northern Malawi: A quasi experiment. Journal of HIV/AIDS & Social Services, 18(3), 229–247. https://doi.org/10.1080/15381501.2019.1620664

 Web of Science ®Google Scholar

James, S., Reddy, P., Ruiter, R. A. C., McCauley, A., & van den Borne, B. (2006). The Impact of an HIV and AIDS Life Skills Program on Secondary School Students in KwaZulu-Natal, South Africa. AIDS Education and Prevention: official Publication of the International Society for AIDS Education, 18(4), 281–294. https://doi.org/10.1521/aeap.2006.18.4.281

 PubMed Web of Science ®Google Scholar

Mba, C. I., Obi, S. N., & Ozumba, B. C. (2007). The impact of health education on reproductive health knowledge among adolescents in a rural Nigerian community. Journal of Obstetrics and Gynaecology: The Journal of the Institute of Obstetrics and Gynaecology, 27(5), 513–517. https://doi.org/10.1080/01443610701478991

 PubMedGoogle Scholar

Gelfond, J., Dierschke, N., Lowe, D., & Plastino, K. (2016). Preventing pregnancy in high school students: Observations from a 3-year longitudinal, quasi-experimental study. American Journal of Public Health, 106(S1), S97–s102. https://doi.org/10.2105/AJPH.2016.303379

 PubMedGoogle Scholar

Mason-Jones, A. J., Flisher, A. J., & Mathews, C. (2013). Peer education training for sexual health and well-being in public high schools in South Africa: Is it enough to change peer educators themselves? Journal of Child and Adolescent Mental Health, 25(1), 35–42. https://doi.org/10.2989/17280583.2012.730998

 PubMedGoogle Scholar

Lan, C.-W., Lightfoot, A., Gere, D., Taboada, A., Meyer, K., Harwood, J., & Milburn, N. G. (2019). Live or virtual? comparing two versions of amp!, a theater-based sexual health intervention for adolescents. American Journal of Sexuality Education, 14(3), 292–314. https://doi.org/10.1080/15546128.2019.1586270

 Web of Science ®Google Scholar

Cartagena, R. G., Veugelers, P. J., Kipp, W., Magigav, K., & Laing, L. M. (2006). Effectiveness of an HIV prevention program for secondary school students in Mongolia. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 39(6), 925.e9-16–925.16. https://doi.org/10.1016/j.jadohealth.2006.07.017

 PubMedGoogle Scholar

Rohrbach, L. A., Berglas, N. F., Jerman, P., Angulo-Olaiz, F., Chou, C.-P., & Constantine, N. A. (2015). A rights-based sexuality education curriculum for adolescents: 1-year outcomes from a cluster-randomized trial. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 57(4), 399–406. https://doi.org/10.1016/j.jadohealth.2015.07.004

 PubMed Web of Science ®Google Scholar

Taylor, M., Jinabhai, C., Dlamini, S., Sathiparsad, R., Eggers, M. S., & De Vries, H. (2014). Effects of a teenage pregnancy prevention program in KwaZulu-Natal, South Africa. Health Care for Women International, 35(7-9), 845–858. https://doi.org/10.1080/07399332.2014.910216

 PubMed Web of Science ®Google Scholar

Lohan, M., Aventin, Á., Clarke, M., Curran, R. M., McDowell, C., Agus, A., McDaid, L., Bonell, C., & Young, H. (2018). Can teenage men be targeted to prevent teenage pregnancy? a feasibility cluster randomised controlled intervention trial in schools. Prevention Science: The Official Journal of the Society for Prevention Research, 19(8), 1079–1090. https://doi.org/10.1007/s11121-018-0928-z

 PubMed Web of Science ®Google Scholar

Markham, C. M., Peskin, M. F., Shegog, R., Baumler, E. R., Addy, R. C., Thiel, M., Escobar-Chaves, S. L., Robin, L., & Tortolero, S. R. (2014). Behavioral and psychosocial effects of two middle school sexual health education programs at tenth-grade follow-up. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 54(2), 151–159. https://doi.org/10.1016/j.jadohealth.2013.10.204

 PubMed Web of Science ®Google Scholar

Markham, C. M., Tortolero, S. R., Peskin, M. F., Shegog, R., Thiel, M., Baumler, E. R., Addy, R. C., Escobar-Chaves, S. L., Reininger, B., & Robin, L. (2012). Sexual risk avoidance and sexual risk reduction interventions for middle school youth: a randomized controlled trial. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 50(3), 279–288. https://doi.org/10.1016/j.jadohealth.2011.07.010

 PubMed Web of Science ®Google Scholar

Rohrbach, L. A., Donatello, R. A., Moulton, B. D., Afifi, A. A., Meyer, K. I., & De Rosa, C. J. (2019). Effectiveness evaluation of it’s your game: keep it real, a middle school HIV/Sexually Transmitted infection/pregnancy prevention program. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 64(3), 382–389. https://doi.org/10.1016/j.jadohealth.2018.09.021

 PubMed Web of Science ®Google Scholar

Tortolero, S. R., Markham, C. M., Peskin, M. F., Shegog, R., Addy, R. C., Escobar-Chaves, S. L., & Baumler, E. R. (2010). It’s your game: Keep it real: Delaying sexual behavior with an effective middle school program. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 46(2), 169–179. https://doi.org/10.1016/j.jadohealth.2009.06.008

 PubMed Web of Science ®Google Scholar

Peskin, M. F., Shegog, R., Markham, C. M., Thiel, M., Baumler, E. R., Addy, R. C., Gabay, E. K., & Emery, S. T. (2015). Efficacy of it’s your game-tech: A computer-based sexual health education program for middle school youth. The Journal of Adolescent Health: official Publication of the Society for Adolescent Medicine, 56(5), 515–521. https://doi.org/10.1016/j.jadohealth.2015.01.001

 PubMed Web of Science ®Google Scholar

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article [and/or] its supplementary materials.