In a study of trachoma in owl monkeys, it was found that owl monkeys are equally susceptible to low and high doses of trachoma and that resistance to reinfection persisted for six months in the majority of animals. Previous infections with a single trachoma type did not elicit greater resistance than previous infections with two types.
Both serum antibodies and eye secretion titers correlated well with resistance to reinfection, but it is not as yet clear if either or both play a substantial role in immunity to trachoma.
Fraser CO, McComb DE, Murray ES, MacDonald AB. Immunity to Chlamydial Infections of the EyeIV. Immunity in Owl Monkeys to Reinfection With Trachoma. Arch Ophthalmol. 1975;93(7):518-521. doi:10.1001/archopht.1975.01010020534010