Objectives To prospectively evaluate the protective value of consistent and correct use of latex condoms against the acquisition of Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis.

Methods Patients (N=929) attending clinics that treat sexually transmitted infections (STIs) were prospectively followed for up to 6 months. Urine STI nucleic acid amplification testing was performed at baseline, 3 months and 6 months. Participants were instructed to respond to daily prompts from a handheld device by completing a report for each penile-vaginal sexual intercourse event. Generalised estimating equation models examined associations of consistent as well as consistent and correct condom use with STI incidence over 3-month intervals.

Results Consistent condom use was not significantly associated with STI incidence (Estimated OR (EOR)=0.75; 95% CI (CI) 0.43 to 1.30; p=0.31). However, individuals who used condoms both correctly and consistently were estimated to have 59% lower odds of acquiring an STI (EOR=0.41; 95% CI  0.19 to 0.90; p=.026), compared to those who did not.

Conclusions The correct as well as the consistent use of condoms greatly reduces the odds of non-viral STI acquisition.