Optimal screening strategy design for chlamydia infection

Chlamydia infection (CT) is caused by the bacterium, Chlamydia trachomatis, and is one of the most commonly reported sexually transmitted diseases in the United States. CT is often a "silent" disease with the majority of infected people having no symptoms. However, it can progress to serious reproductive and other health problems with both short-term and long-term consequences. CT can be accurately diagnosed through nucleic acid amplication tests and can be easily treated and cured with antibiotics. Identifying asymptomatically infected individuals efficiently is a key public health challenge. The Centers for Disease Control and Prevention (CDC) and the US Preventive Service Task Force recommend a screening strategy that carries yearly CT testing of all sexually active women age 25 or younger, older women with risk factors, and all pregnant women. There is no evidence-based justification of the optimality of this strategy in terms of cost and effectiveness, as opposed to alternative strategies. Since CT incidence rate varies over the age spectrum, age-specic screening methods may be cost-effective in controlling the disease. In this dissertation, an age-structured compartment model is developed for CT transmission and intervention (e.g., screening and treatment). Age-dependent per-encounter CT acquisition risk is estimated based on clinical observations of age-specific CT prevalence and sexual behavior, through a Monte-Carlo sampling approach. Cost-effectiveness analysis is performed on a series of CT screening strategies based on this age-structured model. Optimization problems are formulated to minimize the per capita total cost, and solved under different assumptions on the structure of the screening strategies.