Cost effectiveness of <i>Chlamydia trachomatis</i> screening in women in Brazil

<b>Background:</b> <i>Chlamydia trachomatis</i> is the most prevalent bacterial sexually transmitted infection (STI) worldwide, often asymptomatic in women and associated with severe reproductive complications. In Brazil, population-based screening is not routinely implemented. This study aimed to evaluate the cost-effectiveness of <i>Chlamydia trachomatis</i> screening among asymptomatic women in different age groups. <b>Methods:</b> A hypothetical cohort of 10,000 women was simulated in a Markov model over 10 years, stratified into three age groups: 14-25, 26-30, and 31-35 years. We compared three screening strategies: annual screening, screening every three to 4 years, and no screening. Clinical outcomes included pelvic inflammatory disease (PID), infertility, ectopic pregnancy, and chronic pelvic pain. Costs were presented in Brazilian Reals (BRL) and U.S. Dollars (USD), and the main outcome was the incremental cost-effectiveness ratio (ICER) per significant case averted. <b>Results:</b> Annual screening in women aged 14-25 was the most cost-effective strategy, preventing 7,274 significant health outcomes at a total cost of R$ 7.39 million (USD 1.48 million), resulting in an ICER of R$ 1,015 (USD 203) per case averted. For women aged 26-30, screening every 3 years was more cost-effective, while for those aged 31-35, screening every 4 years yielded the best value for money. <b>Conclusions:</b> targeted chlamydia screening strategies by age group are cost-effective in Brazil. Annual screening of women aged ≤25 years, in particular, offers substantial health benefits at acceptable costs and should be prioritized in STI control programs.