How long can chlamydia go undetected and not be transmitted to somebody else?

Chlamydia can go undetected and untreated for many months, even years, in both men and women. This can lead to very serious problems including pelvic inflammatory disease (PID) and infertility. However, although it’s possible to have chlamydia for a long time without knowing it, while a person may not have symptoms and may be unaware they have the infection, they are still able to pass it to someone else. This silent spread is one of the things that makes chlamydia so difficult to control. Using condoms every time you have sex is one of the most effective ways to help prevent the transmission of sexually transmitted infections (STI), like chlamydia.