Women seem to be more susceptible than men.
The incidence of infection seems to be directly related to sexual activity and geography, with urban populations having higher incidences. The incidence in pregnant women overall is 4 to 10 percent. Diagnosis of inclusion conjunctivitis is often difficult. Many times there are little, if any, symptoms. Infants whose mothers have untreated chlamydial infection have a 30 to 40 percent chance of developing neonatal chlamydial conjunctivitis.