Why are chlamydia rates on the rise?

Decreased condom use, increased screening,

a lack of awareness, and funding cut backs are likely to blame, say experts

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Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.


  •  In 2017, nearly 2.3 million cases of chlamydia, gonorrhea, and syphilis were diagnosed in the US.
  • Chlamydia is by far the most common notifiable STI, with 1.7 million cases diagnosed in 2017—a 22% increase since 2013.
  • A drop off in condom use, increased screening, a lack of funding for STI prevention programs, and a lack of awareness about the disease are thought to be some of the main reasons behind this increase.

We’re No. 1! But in this instance, the distinction is no cause for celebration. The United States has the highest sexually transmitted infection (STI) rates in the industrialized world.  And they’ve been steadily increasing, with a new record set in each of the last several years. In 2017 (the last year for which complete data is available), nearly 2.3 million cases of chlamydia, gonorrhea, and syphilis were diagnosed.

Chlamydia is by far the most common notifiable STI, with 1.7 million cases diagnosed in 2017. That’s a 22% increase since 2013, according to a report by the Centers for Disease Control and Prevention (CDC).

“We have seen steep and sustained increases over the last five years,” said Dr. Gail Bolan, director of the Division of STD Prevention at the CDC. “Usually there are ebbs and flows, but this sustained increase is very concerning. We haven’t seen anything like this for two decades.”

“We are sliding backward,” said Jonathan Mermin, director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. “It is evident the systems that identify, treat, and ultimately prevent STDs are strained to near-breaking point.”

So what’s behind it? Why are chlamydia rates rising so dramatically?

Why are chlamydia rates rising?

Researchers think the rates of chlamydia, along with other STIs, are rising for four main reasons.

1. A rise in condomless sex

The development of effective treatments for HIV — and prevention in the form of PrEP — has led to a decline in condom use at the same time that location-based dating apps have made sex more easily accessible.

PrEP stands for Pre-Exposure Prophylaxis. The Federal Drug Administration (FDA) approved a medication known as Truvada in 2004 to treat HIV in combination with other medications.  In 2012, the FDA approved Truvada for use as PrEP for people who do not have HIV.

PrEP is a pill taken daily by people who do not have HIV to protect against HIV. There’s also a type of medication called PEP which stands for Post-Exposure Prophylaxis. As the name suggests, PEP is taken after a potential exposure to HIV to prevent becoming infected. Both are incredible advancements in reducing HIV transmission rates but may also be discouraging condom use and driving increases in the transmission rates of STIs, including chlamydia.

“Experts say many factors have contributed to the rapid rise, though the biggest one may be less frequent condom use,” NBC News reported. “It’s less clear whether dating apps, like Tinder, have contributed in some way to the spread of STDs, though some researchers think they have.”

2. Better detection and screening

In the vast majority of cases, chlamydia causes no symptoms. But it can cause serious complications in women. Rates of chlamydia are highest among young women: the CDC says 1 in 20 sexually active females between the ages of 14 and 24 are believed to be infected. That group has been targeted for routine chlamydia screening. So part of the increase in diagnosed cases could be due to more women being tested in some areas.

3. Cuts in STI-prevention programs

Public health programs — never particularly well funded in the U.S. — have cut even further in recent years. “It’s not a coincidence STIs are skyrocketing — state and local STI programs are working with effectively half the budget they had in the early 2000s,” said David Harvey, executive director of the National Coalition of STI Directors, in a statement. “If our representatives are serious about protecting American lives, they will provide adequate funding to address this crisis. Right now, our STI prevention engine is running on fumes.”

4. A lack of awareness

Because of reduced funding, STI clinics have been shuttered in some areas, leading to a reduction in education. “We’ve seen a tremendous increase [in STIs] in many areas primarily due to the eroding public health infrastructure,” Michael Fraser, executive director of the Association of State and Territorial Health Officials, told NBC News. “The lack of funding at the state and local level to really invest in prevention work is not just about medications, it’s about disease investigators who meet with the individual who is infected and talk about their behavior and do contact tracing to try to prevent the future spread.”

What is chlamydia?

Chlamydia is an STI caused by the Chlamydia trachomatis bacterium. It’s passed along during sexual contact with an infected person’s penis, vagina, mouth or anus. Ejaculation doesn’t have to occur for it to be transmitted. Chlamydia can also be spread from mother to infant during childbirth.

According to the agency, only 10% of men and 5 to 30% of women who test positive for a chlamydia infection will develop symptoms.

In women, chlamydia can cause pain, irritation, a vaginal discharge, or pain while urinating.

If left untreated, chlamydia can spread to the cervix, uterus, ovaries and fallopian tubes, causing pelvic inflammatory disease (PID), which is signified by abdominal pain or pelvic pain. It can have serious implications for women’s fertility, causing scarring or blockages in the fallopian tubes. This can cause infertility or an ectopic pregnancy, which can be fatal.

In men, chlamydia complications are less severe. It can lead to urethritis (a swelling in the urethra), which causes pain while urinating and discharge. Untreated chlamydia can lead to epididymitis, a swelling in the tubes in back of the testicles, causing pain.

Both women and men can be infected with chlamydia in the rectum, which can cause pain, discharge or bleeding.

How do you prevent chlamydia?

The only way to absolutely avoid STIs is to abstain from sexual contact. The next best way is to use condoms during intercourse.

If you have symptoms of chlamydia, see a health-care provider as soon as possible for testing. It’s also a good idea to ask your healthcare provider about routine STI testing and what’s right for you.

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