Chlamydia can last indefinitely without treatment. Most untreated infections remain detectable for at least 60 days, and some persist for years. With antibiotics, the infection clears in about a week. The answer depends entirely on whether you get treated and how quickly.
How Long Chlamydia Lasts Without Treatment
If you don’t take antibiotics, chlamydia doesn’t go away on a predictable schedule. Studies tracking untreated women found that most infections remained positive on testing for more than 60 days, and smaller case series have documented infections persisting for years. Some infections do eventually clear on their own, but even when standard tests come back negative, there’s often evidence that the bacteria are still present in the tissue.
The reality is that researchers haven’t been able to pin down a median duration for untreated chlamydia. There’s no reliable curve showing that X percent of infections clear by Y months. For practical purposes, you should assume an untreated chlamydia infection will stick around until you take antibiotics.
How Long Treatment Takes
The standard treatment is a 7-day course of doxycycline, taken twice a day. There’s also a once-daily delayed-release version that works equally well over the same 7 days. An alternative is a single dose of azithromycin, which clears the infection with one pill.
How long you need to avoid sex depends on which treatment you take. With the 7-day doxycycline course, you can resume sexual activity the day after finishing your last dose. With the single-dose azithromycin, wait a full week after taking it. During that window, you’re still potentially contagious.
Why You Might Not Know You Have It
The reason chlamydia lingers so long in many people is that it frequently causes no symptoms at all. Most women and a significant number of men never notice anything wrong. When symptoms do appear, they typically show up one to three weeks after exposure, but the absence of symptoms doesn’t mean the infection is mild or harmless. It’s actively damaging tissue even when you feel fine.
If you think you’ve been exposed, testing is reliable about one week after contact and catches almost all infections by two weeks. Testing earlier than that risks a false negative because the bacteria haven’t multiplied enough to detect.
What Happens If It Lasts Too Long
The longer chlamydia goes untreated, the higher the risk of serious complications. In women, the main concern is pelvic inflammatory disease (PID), an infection that spreads to the uterus and fallopian tubes. Mathematical modeling suggests that about half of all PID cases that will develop from a chlamydia infection occur within roughly 228 days (about 7.5 months). But PID can also develop much sooner. It can happen at any point during an active infection, not just after a long delay.
PID can lead to chronic pelvic pain, scarring of the fallopian tubes, and infertility. In men, the primary complication is epididymitis, a painful inflammation of the tube that stores and carries sperm. Acute cases last less than six weeks, but chronic epididymitis can cause discomfort for months.
Reinfection After Treatment
Getting treated once doesn’t protect you from getting chlamydia again. Reinfection rates are surprisingly high. Among young women aged 15 to 19, roughly 1 in 5 tested positive again within 12 months of being treated. By 24 months, the repeat infection rate climbed to between 24 and 36 percent in that age group, depending on the population studied. Even among women in their late twenties and early thirties, about 10 to 15 percent had a repeat infection within two years.
These numbers reflect a mix of reinfection from untreated partners and new exposures. This is why the CDC recommends retesting three months after treatment for anyone who tests positive for chlamydia. That three-month retest isn’t checking whether your antibiotics worked. It’s checking whether you’ve been reinfected since then.
The Bottom Line on Timing
Untreated chlamydia lasts months at minimum and potentially years. With a standard 7-day antibiotic course, the active infection clears within that week. You’ll need to avoid sex for 7 days after a single-dose treatment or until the day after finishing a week-long course. A retest at three months confirms you haven’t picked it up again. The infection itself is straightforward to cure, but only if you know it’s there.