Evaluation of a sex education lesson on chlamydia to see whether it increases the likelihood that young adults will use condoms to protect against this sexually transmitted infection (STI)

INTERVENTION: In the experimental group, participants will receive the school's standard teaching on STIs plus a theory‐ and evidence‐based lesson on chlamydia. In the control group participants will receive just their school's usual teaching on STIs. The teaching will last 40 minutes. The duration of follow‐up is three months. CONDITION: Chlamydia trachomatis ; Infections and Infestations ; Sexually transmitted chlamydial infection of other sites PRIMARY OUTCOME: Intention to use condoms during vaginal sex with casual sexual partners over the next three months SECONDARY OUTCOME: 1. Use of condoms during vaginal sex with casual sexual partners over three months post delivery; 2. Perceived likelihood of chlamydia; 3. Perceived severity of chlamydia; 4. Response efficacy for condom use; 5. Self‐efficacy for using condoms during vaginal sex with casual sexual partners over the next three months INCLUSION CRITERIA: 1. Aged 13‐16 years old 2. Attending a secondary school in England which has a Sex and Relationships Education (SRE) protocol and curriculum 3. Have not received any previous formal education on STIs through school