Introduction Population-based studies help provide more-robust prevalence estimates and related factors, which are needed to drive sexually transmitted infection (STI) prevention and control programmes. We use data from the Brazilian Survey of Knowledge, Attitudes, and Practices (PCAP) to examine the prevalence of self-reported STIs and its association with demographics, behaviour, and the uptake of interventions.

Methods A probability sample survey was conducted in 2013 (PCAP-2013; n=12,000) and in 2008 (PCAP-2008; n=8,000) among men and women aged 15–64. The participants completed the survey in their homes through computer-assisted face-to-face interviews and self-interviews. We describe the age-specific and sex-specific prevalence of self-reported STIs in relation to demographics, behavioural factors, and the uptake of interventions and explore associated changes since the PCAP-2008.

Results Overall, 9.4% of men and 5.3% of women reported having had an STI in 2013. This prevalence decreased from that in 2008 (15.9% in men and 8.8% in women). In 2013, self-reported STIs were mainly urethral discharge (5.8%) among men and genital ulcers (2.9%) among women. Men sought care and treatment more often than women did during their most recent experience of STI symptoms (care: 85.7% and 81.2%; treatment: 77.5% and 68.7%, respectively). Self-reported STI infections were associated with increasing age, decreasing socioeconomic status, current or previous drug use, sex with a casual partner in the last 12 months (for both sexes), sex with a same sex partner, and no condom use during the last sexual intercourse (for men), and non-indigenous status and one or more previous HIV tests (for women).

Conclusion This probability sample survey highlights a decrease in STIs for men and women in Brazil. Women carry a higher STI burden than men do. The increases in health care-seeking behaviour and treatment received when presenting symptoms are encouraging. Increasing age, casual sexual partners, and drug use are the main risk factors for STI acquisition.