How common is chlamydia?
Chlamydia is the most common STI caused by bacteria. Nearly 2 million cases of chlamydia were reported to the CDC in 2019. The number of infections is likely even higher. When compared to previous years, 2019 infection rates increased among people of all genders, all races and ethnicities, and in every region of the U.S. Most cases of chlamydia are asymptomatic, which means there are no signs or symptoms of an infection. Many of these cases likely go unreported.
Certain demographic characteristics (like age, gender and race) may make you more likely to get diagnosed with chlamydia. You’re more likely to get diagnosed if you’re:
- A teen or young adult aged 15 to 24. More than half of all diagnosed chlamydia cases in the U.S. occur in this age group.
- A cisgender woman aged 15 to 24. Young women in this age group are targeted for chlamydia screenings, and the rate of infection among those who are tested is high.
- A man who has sex with men (MSM). Chlamydia infections disproportionately affect men who have sex with men.
- Black and non-Hispanic. Chlamydia infections disproportionately affect non-Hispanic Black populations.
Higher rates of transmission among certain groups are less about sexual behavior and more about networks and lack of access to STI prevention resources. For example, chlamydia is more likely to spread from person to person within communities that have higher infection rates. And it’s more likely to spread among groups that don’t have easy access to sex education or barriers to STIs like condoms and dental dams.