Chlamydia in United States

United States

Chlamydia, a bacterial infection that can infect both men and women, is the most commonly reported sexually transmitted infection (STI) in the United States. More than 1.6 million chlamydia cases were reported in 2022. However, the true number of cases is difficult to determine because people may not seek testing if they do not have symptoms. Cases had steadily increased over the last decade, although this trend appears to have reversed in 2020. The Centers for Disease Control and Prevention (CDC) cautions that COVID-19-related decreases in health care use and STI screenings likely led to the underdiagnosis of chlamydial infections. 

Chlamydia infections often have no symptoms, but can still cause permanent damage to reproductive organs. Among women, untreated chlamydia can lead to pelvic inflammatory disease, inability to get pregnant or ectopic pregnancy, a life-threatening condition in which the fertilized egg develops outside the uterus. Untreated chlamydia in men rarely causes life-threatening damage but can cause painful testicular swelling (epididymitis).

Social conditions such as poverty, low educational attainment and unemployment can present barriers to accessing quality sexual health care. Living without consistent STI screening and medical care can lead to higher rates of chlamydia and untreated chlamydia.

According to America’s Health Rankings analysis, populations with higher rates of chlamydia include:

• Females, who are more likely to be diagnosed with chlamydia than males, due in part to routine screening and a higher frequency of symptoms. 
• Black, American Indian/Alaska Native, and Hawaiian/Pacific Islander populations compared with Hispanic, multiracial, white and Asian populations.

Other populations with higher rates of chlamydia include:

• Youth ages 15-24 compared with older age groups. 

Effective prevention and treatment strategies can combat the spread of chlamydia. While abstinence is the only completely effective prevention strategy, having a single sexual partner, reducing the number of sex partners, and proper use of latex condoms and/or dental dams can reduce transmission. 

Screening can prevent the development of pelvic inflammatory disease and other conditions from untreated chlamydia. Providers should integrate screening for chlamydia and other STIs into regular medical care. Annual screening is recommended by the CDC for:

• Sexually active and/or pregnant women younger than 25.
• Sexually active and/or pregnant women age 25 and older who have a new partner, multiple partners or a partner who tested positive for an STI.
• Sexually active gay or bisexual men.

If diagnosed, chlamydia is easily treated with antibiotics combined with a short period of abstinence from sex. Expedited partner therapy is available in some states and allows providers to prescribe antibiotics for sexual partners of individuals diagnosed with chlamydia, which has been shown to prevent reinfection. The CDC also recommends doxycycline postexposure prophylaxis (doxy PEP) to prevent chlamydia among high-risk populations, including men who have sex with men and transgender women.

Healthy People 2030 has an objective to increase the proportion of sexually active female adolescents and young women who get screened for chlamydia. 

Additionally, the U.S. Department of Health and Human Services has developed a national strategic plan with detailed approaches, goals and progress-tracking indicators to address the STI epidemic and reduce STI-related health disparities.

Bachmann, Laura H., Lindley A. Barbee, Philip Chan, Hilary Reno, Kimberly A. Workowski, Karen Hoover, Jonathan Mermin, and Leandro Mena. “CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024.” MMWR. Recommendations and Reports 73, no. 2 (June 6, 2024): 1–8. https://doi.org/10.15585/mmwr.rr7302a1.

Committee on Gynecologic Practice and Committee on Adolescent Health Care. “ACOG Committee Opinion No. 737: Expedited Partner Therapy.” Obstetrics & Gynecology 131, no. 6 (June 2018). https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2018/06/expedited-partner-therapy.

Das, Breanne, Jocelyn Ronda, and Maria Trent. “Pelvic Inflammatory Disease: Improving Awareness, Prevention, and Treatment.” Infection and Drug Resistance Volume 9 (August 2016): 191–97. https://doi.org/10.2147/IDR.S91260.

Gable, Jennifer, Jennifer Eder, and Cynthia Mollen. “Preventing Chlamydia and Gonorrhea Reinfection through Increased Use of Expedited Partner Therapy.” Evidence to Action Brief. Philadelphia: PolicyLab at CHOP Research Institute, December 2016. https://policylab.chop.edu/sites/default/files/pdf/publications/Preventing_Chlamydia_Gonorrhea_Reinfection_through_Increased_Use_of_EPT.pdf.

Kreisel, Kristen M., Ian H. Spicknall, Julia W. Gargano, Felicia M.T. Lewis, Rayleen M. Lewis, Lauri E. Markowitz, Henry Roberts, et al. “Sexually Transmitted Infections Among US Women and Men: Prevalence and Incidence Estimates, 2018.” Sexually Transmitted Diseases 48, no. 4 (April 2021): 208–14. https://doi.org/10.1097/OLQ.0000000000001355.