Basic information for topics, such as "What is it?" and "How many people are affected?" is available in the About Sexually Transmitted Diseases (STDs) section. Answers to other Frequently Asked Questions (FAQs) specific to STDs and Sexually Transmitted Infections (STIs) are in this section.
STDs/STIs affect men and women of all races, backgrounds, sexual orientations, and economic levels. Anyone who is having or has had vaginal, anal, or oral sex has some degree of risk for an STI. In fact, some STIs can be passed through sexual play that does not involve intercourse.
You can analyze your risk for STDs/STIs with the STD Wizard —a free interactive online tool based on the Centers for Disease Control and Prevention's (CDC's) STD Treatment Guidelines. The STD Wizard recommends tests and vaccines based on your responses concerning some of your personal characteristics and behaviors. You can use these recommendations to start a discussion with your health care provider about your STD/STI risk and the tests you may need. The STD Wizard is available in both English and Spanish.
The most reliable ways to avoid STDs/STIs are to abstain from sexual contact or to be in a long-term monogamous relationship with a partner who has been tested and is uninfected.1 In addition, the following measures can also help you avoid STIs:
- Know your sexual partners' STI and health history.
- Talk to your health care provider about your risk, and get tested for STIs.
- Get vaccinated against hepatitis A virus, hepatitis B virus, and human papillomavirus.
- Use latex condoms correctly and for all sexual activity.
Remember, however, that while condoms greatly reduce the chance of getting certain STIs, such as gonorrhea, condoms cannot fully protect against infection because viruses and some bacteria can be passed from person to person by skin-to-skin contact in the genital area not covered by a condom.2
You should see your health care provider for treatment as soon as possible after receiving a diagnosis of an STD/STI. You also should notify, either yourself or with the help of the local health department, all recent sex partners and advise them to see their health care providers and be treated. These steps will reduce your risk of becoming re-infected, help avoid spreading the STI to other people, and decrease the risk that your previous sexual partners will develop serious complications from the STI. You and all of your sex partners must avoid sex until treatment is complete and all symptoms have disappeared.
In the case of STIs caused by viruses with no cure (for example, HIV, genital herpes, or hepatitis), special care and preventive measures can help control the infection, limit symptoms, and help maximize health.
STDs/STIs in women can cause pelvic inflammatory disease, which may result in infertility and chronic pelvic pain.
Men with STIs also can have problems with infertility.2
Additionally, a person with an STI other than HIV is two to five times more likely to contract HIV when exposed to an HIV-infected partner than a person without an STI. If a person is already HIV positive, having another STI increases the chances that he or she will pass the virus on to his or her sexual partner.3
Certain STIs, such as gonorrhea, chlamydia, HIV, and syphilis, can pass from a pregnant woman to the fetus in her womb. The effects can be life threatening, as is the case with HIV and syphilis. Other STIs, especially if left untreated, can cause a range of health problems in the infant, including deafness, blindness, and intellectual disability.
Having an STD/STI increases a person's risk for several types of cancer.
Certain high-risk types of human papillomavirus (HPV) can cause cervical cancer in women. In men, HPV infection can lead to the development of penile cancers. HPV also can cause cancers of the mouth, throat, and anus in both sexes.6
Acquiring viral hepatitis B or C puts a person at risk for liver cancer, and untreated HIV/AIDS increases risk for several types of rare cancers, including lymphomas, sarcomas, and cervical cancer.4
In most cases, STDs/STIs are linked to infertility primarily when they are left untreated.
For instance, chlamydia and gonorrhea are bacterial STIs that can be cured easily with antibiotics. But if left untreated, 10% to 20% of chlamydial and gonorrheal infections in women can result in pelvic inflammatory disease (PID)—a condition that can cause long-term complications, such as chronic pelvic pain, ectopic pregnancy (pregnancy outside of the uterus), and infertility.7,8,9
Additionally, some infections may not cause symptoms and may go unnoticed. These undiagnosed and untreated infections can lead to severe health consequences, especially in women, causing permanent damage to reproductive organs and infertility.7,8,9,10
Infertility from an STI is less common among men, but it does occur.9 More commonly, untreated chlamydia and gonorrhea infections in men may cause epididymitis, a painful infection in the tissue surrounding the testicles, or urethritis, an infection of the urinary canal in the penis, which causes painful urination and fever.11
Additional information on PID is available from CDC.
- Centers for Disease Control and Prevention. (2015). Sexually transmitted diseases (STDs): Genital herpes. Retrieved December 30, 2015, from http://www.cdc.gov/std/herpes
- Centers for Disease Control and Prevention. (2015). Sexually transmitted diseases (STDs): STDs & infertility. Retrieved December 30, 2015, from http://www.cdc.gov/std/infertility
- Centers for Disease Control and Prevention. (2015). Sexually transmitted diseases (STDs): HIV/AIDS & STDs. Retrieved December 30, 2015, from http://www.cdc.gov/std/hiv
- Simard, E. P., Pfeiffer, R. M., & Engels, E. A. (2011). Cumulative incidence of cancer among individuals with acquired immunodeficiency syndrome in the United States. Cancer, 117, 1089–1096.
- Centers for Disease Control and Prevention. (2015). 2015 sexually transmitted diseases treatment guidelines. Retrieved December 30, 2015, from http://www.cdc.gov/std/tg2015/
- Committee on Infectious Diseases. (2012). HPV vaccine recommendations. Pediatrics, 129, 602–605.
- Centers for Disease Control and Prevention. (2015). Sexually transmitted diseases (STDs): Pelvic inflammatory disease. Retrieved December 24, 2015, from http://www.cdc.gov/std/PID
- Centers for Disease Control and Prevention. (2015). Sexually transmitted disease surveillance 2014. Atlanta, GA: U.S. Department of Health and Human Services. Retrieved December 22, 2015, from http://www.cdc.gov/std/stats14/surv-2014-print.pdf (PDF – 4 MB)
- Stamm, W. E. (2008). Chlamydia trachomatis infections of the adult. In G. Gross & S. K. Tyring (Eds.), Sexually transmitted diseases (4th ed., pp. 575–593). New York: McGraw Hill.
- Hillis, S. D., & Wasserheit, J. N. (1996). Screening for chlamydia—A key to the prevention of pelvic inflammatory disease. New England Journal of Medicine, 334, 1399–1401.
- Centers for Disease Control and Prevention. (2015). Sexually transmitted diseases (STDs): Gonorrhea. Retrieved December 24, 2015, from http://www.cdc.gov/std/gonorrhea