A game-theoretical model of optimal condom usage to prevent chlamydia infection

Chlamydia trachomatis is one of the most common sexually transmitted infections worldwide, often asymptomatic and leading to severe reproductive health complications if untreated. In this work, we construct a game-theoretic model to investigate individual decisions regarding condom usage as a preventive measure against chlamydia infection. We consider two behavioral scenarios: non-discriminating and discriminating populations. In the first scenario, condom usage rates are independent of observed chlamydia symptoms. In the second scenario, individuals always utilize condoms upon recognizing chlamydia symptoms. Our findings demonstrate that the optimal population condom usage remains below the herd immunity threshold in both scenarios if the cost of condom usage is not negligible. The optimal condom usage is closer to herd immunity level in a non-discriminating population if the cost of condom usage relative to the cost of infection is close to zero. We performed uncertainty and sensitivity analyses to establish the robustness of our conclusions with respect to the uncertainty in the epidemiological model parameters. These results emphasize the critical role of reducing the perceived and actual costs of condom use in preventing chlamydia infections.