Is it rare to contract chlamydia through oral sex?

No.: Less common than herpes, but can be transmitted orally to whoever is performing the oral sex. Can cause chlamydial pharyngitis!

Yes, quite rare: This is a bit controversial. For decades, it was gospel among STD and infectious disease experts that oral chlamydia is very rare and not transmitted by oral sex. With better lab tests, we now know oral chlamydia is somewhat more frequent, but it's still uncommon compared with genital infeciton, and CDC recommends against oral testing. Oral to genital transmission is very rare.