County Health Rankings Model

Sexually Transmitted Infections

In the model

Use County Health Rankings’ model of health to explore the measures that influence how long and how well we live.

Loading interactive model…

About

Number of newly diagnosed chlamydia cases per 100,000 population. The 2022 County Health Rankings used data from 2019 for this measure.

Chlamydia incidence rates are associated with unsafe sexual activity. Chlamydia is the most common bacterial sexually transmitted infection (STI) in North America and is one of the major causes of tubal infertility, ectopic pregnancy, pelvic inflammatory disease, and chronic pelvic pain.[1] STIs are associated with a significantly increased risk of morbidity and mortality, including increased risk of cervical cancer, infertility, and premature death.[2] STIs also have a high economic burden on society. The direct medical costs of managing sexually transmitted infections and their complications in the United States, for example, was approximately 15.6 billion dollars in 2008.[3] This measure is also significant to health equity as chlamydia disproportionally affects underserved communities, particularly adolescent minority women.[4]

Find strategies to address Sexually Transmitted Infections

Data and methods

Data Source

National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention

Data on sexually transmitted infections were provided by the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP). The NCHHSTP is responsible for public health surveillance, prevention research, and programs to prevent and control human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), other sexually transmitted diseases (STDs), viral hepatitis, and tuberculosis (TB). Center staff work in collaboration with governmental and nongovernmental partners at community, state, national, and international levels, applying well-integrated multidisciplinary programs of research, surveillance, technical assistance, and evaluation.

Website to download data
For more detailed methodological information

Key Measure Methods

Sexually Transmitted Infections is a rate

Sexually Transmitted Infections is the number of newly diagnosed chlamydia cases per 100,000 population in a county. Rates measure the number of events in a given time period (generally one or more years) divided by the average number of people at risk during that period. Rates help us compare risks of health factors across counties with different population sizes.

Some data are suppressed

A missing value is reported for counties with 1 to 3 cases in the time frame.

Measure limitations

An important caveat in chlamydia rate reporting is that increases in reported infections may reflect true increases in disease, but may also reflect expanded screening, use of increasingly sensitive diagnostic tests, increased emphasis on case reporting from providers and laboratories, and improvement in the information systems for reporting. Communities with lower rates of screening may report artificially low rates of chlamydia incidence. Finally, chlamydia is only one of many STIs.

Numerator

The numerator is the number of reported chlamydia cases in a county.

Denominator

The denominator is the total county population.

Can This Measure Be Used to Track Progress

This measure can be used to measure progress with some caveats. It is important to be aware that, although an increase in reported infections may reflect an increase in disease incidence, the increase could also be due to other factors. For example, an increase may also be reflective of expanded screening, better diagnostic tests, or improved reporting by a clinic or local health department. Communities with poor screening rates may have artificially low rates of sexually transmitted diseases.

Digging Deeper

Age1
Gender1
Race1
Education0
Income0
Subcounty Area0

While there is no national source for stratifying STI rates, most states publish STI data, often with age, race, or gender breakdowns. When available, we link to these resources in our Find More Data section.

References

[1] Genuis SJ, Genuis SK. Managing the sexually transmitted disease pandemic: A time for reevaluation. American Journal of Obstetrics & Gynecology. 2004; 191:1103-1112.
[2] Meade CS, Ickovics JR. Systematic review of sexual risk among pregnant and mothering teens in the USA: Pregnancy as an opportunity for integrated prevention of STD and repeat pregnancy. Social Science & Medicine. 2005; 60:661-678.
[3] Owusu-Edusei K Jr, Chesson HW, Gift TL, Tao G, Mahajan R, Ocfemia MC, Kent CK. The estimated direct medical cost of selected sexually transmitted infections in the United States, 2008. Sex Transmitted Disease. 2013; 40(3):197-201.
[4] Cooksey CM, Berggren EK, Lee J. Chlamydia trachomatis Infection in minority adolescent women: a public health challenge. Obstetrical & Gynecological Survey. 2010; 65(11):729–735.

Find strategies in What Works for Health