Heather Corinna replies:

Was her partner ever treated when she was?

Standard procedure when one person is diagnosed with Chlamydia is for a healthcare provider to make clear that all current or recent partners are informed so that they can also be treated at the same time. Some healthcare providers will even just provide two treatments for their patient to bring to their partner. A healthcare provider should also make clear that using condoms for at least a couple of weeks after treatment begins for both partners is advised.

If she was treated and took her full course of treatment properly, and her partner was treated -- and did complete his treatment -- and two months later, with the same partner, she's got it again, then yes, one of them likely did have sex with someone else to contract Chlamydia again. And if that partner got Chlamydia, the sex was probably unprotected, meaning that new risks of other STIs are also an issue.

Or, if one or both of them was not treated, didn't treat properly, or had unprotected sex during that time, it may be the same case of Chlamydia from the first time being passed back and forth between them.

So your friend knows, the safer sex protocol known to be most effective in reducing risks of sexually transmitted infections is as follows:
• Six months of sexual monogamy
• Six months of latex barriers -- condoms for vaginal or anal sex or fellatio (blowjobs), dental dams for cunnilingus (oral sex for women) -- for at least any oral, vaginal and/or anal sex during that time, and
• One full STI screen for both partners at the start of that six months, and one again at the end before going without latex barriers.

If an STI crops up after that period of time and those practices, like Chlamydia, then it's time to start that six month process all over again. Too, if either partner in those screenings tests positive for an STI, then latex barriers need to be used until they test negative again.

As well, if any partner isn't being sexually monogamous, then barriers need to be used no matter how long they've been together or what their test results have been, since possible new STI risks are being introduced by the other partner. Too, if your friend keeps getting Chlamydia, despite treatment for both of them, and she's being monogamous, she can be pretty sure her boyfriend isn't being monogamous, and also isn't using condoms with other partners, so that's not a person she'll want to have sex with without condoms, ever. (Obviously, if she only wants to be in a monogamous relationship, she'll also want to consider staying with him if he's not acting in agreement with that, or if he wants a more open arrangement.) Sounds like no matter what, she needs to have a chat with her boyfriend to find out what's going on, whether that's about him not being monogamous, not taking his treatment properly, getting tested again, or getting him treatment in the first place.

Here's some extra information for you to pass on to her: