Facts, testing, and locations


Sexually transmitted infections, sometimes abbreviated as STIs or STDs, are common infections that spread from one person to another during sex. They're so common that most sexually active people will get at least one in their lifetime. Often there are no symptoms, but if left untreated, STIs can cause serious health issues, and in some cases, death. 

Not all STIs are transmitted the same way. Some STIs, like gonorrhea and chlamydia, are transmitted by bodily fluids. Other STIs, like syphilis or herpes, are passed by skin to skin contact. 

The good news is all STIs, including HIV, are treatable, and many are curable. 



Every year more than 18 million new cases of STIs occur. Both nationally and in Colorado, the rates of STIs are increasing dramatically, and have been for the last four years. STIs are preventable, and there are several ways to avoid them.

Abstinence and/or celibacy are the only ways to completely avoid STIs.Those options may work for some, but for those who don't want to abstain from sex entirely, there are other ways to prevent STIs. 

Limit your sexual partners and have open conversations about sex. This includes conversations about experiences between you and your partner, as well as experiences between your partner and other people. Discuss previous sexual activities and any injection drug use or needle sharing. Talk openly about your history as well.

Condoms and dental dams are an effective way to prevent the transmission of STIs that are passed through body fluids. Using condoms and dental dams can also prevent STIs that are passed skin-to-skin, which includes oral sex. If you aren't using condoms, using lube can help reduce the risk of creating small tears in your skin that increase your chances of coming into contact with STIs.

Some STIs, such as hepatitis A, hepatitis B, and certain strains of human papillomavirus (HPV), can be prevented through vaccination.



If you are having sex, getting tested for STIs is one of the most important things you can do to protect your sexual health. This includes talking with your partners and staying informed. STI testing does not always happen as part of a regular checkup and is often not even discussed. Ask your doctor about testing and start an open and honest conversation about your sexual history.

Getting tested is quick and easy. Your provider may take a blood sample, a urine sample, or a swab from your throat, rectum, or genitals. The type of sex you're having and whether you think you have been exposed to an STI, may help your provider determine what type of STI testing is needed. Since some STIs look and act alike, it’s possible you may be tested for multiple infections. It’s important to know that you can get tested for most STIs whether or not you have any symptoms.

If you are not comfortable talking with your regular health care provider about STIs, many clinics provide confidential, free, or low-cost testing. 


Test easy, rest easy


STI testing may include: 

  • A urine test — you pee into a cup
  • A cheek swab — you rub the inside of your cheek with a soft swab to test for HIV
  • A blood test — a nurse or doctor takes blood from your arm or performs a quick finger prick
  • A physical exam — a nurse or doctor looks at your genital area to check for warts, sores, rashes, irritation, or discharge
  • Testing your sores — a nurse or doctor takes a sample of fluid with a swab from any sores or blisters you have 
  • A swab test - a nurse or doctor uses a swab to gently take discharge or cell samples from your penis, vagina, urethra, cervix, anus, or throat

STI testing recommendations:

  • All adults and adolescents from ages 13 to 64 should be tested at least once for HIV.
  • All sexually active women younger than 25 years should be tested for gonorrhea and chlamydia every year. Women 25 years and older with risk factors such as new or multiple sex partners should also be tested for gonorrhea and chlamydia every year.
  • All pregnant women should be tested for syphilis, HIV, and hepatitis A, B, and C (and vaccinated for A and B if negative) starting early in pregnancy. Pregnant women should also be tested for chlamydia and gonorrhea starting early in pregnancy. Testing should be repeated as needed to protect the health of mothers and their infants.
  • All sexually active gay and bisexual men should be tested at least once a year for syphilis, chlamydia, and gonorrhea. Those who have multiple or anonymous partners should be tested more frequently for STIs (i.e., at three- to six-month intervals).
  • Sexually active gay and bisexual men may benefit from more frequent HIV testing (e.g., every three to six months).
  • Anyone who has unsafe sex or shares injection drug equipment should get tested for HIV and hepatitis C at least once a year.

Chlamydia is one of the most common STIs with an estimated 1.7 million new cases a year in the U.S. Many people who have chlamydia do not know it. Often there are no symptoms. If left untreated, chlamydia can cause infertility and pain in both women and men. Once diagnosed, it is easily cured with antibiotics. For more information, see the CDC's chlamydia fact sheet.

Gonorrhea is common, especially among teens and people in their 20s. Sometimes called "the clap" or "the drip," gonorrhea may not show symptoms. Left untreated, it can cause infertility and pain in both women and men. Once diagnosed, it is easily cured with antibiotics. For more information, see the CDC's gonorrhea fact sheet.

Viral hepatitis is a serious but preventable condition that affects the liver. The three most common types of viral hepatitis are A, B, and C, and each can be transmitted from person to person in different ways. There are many ways a person can reduce the likelihood of acquiring viral hepatitis: Get vaccinated for hepatitis A and hepatitis B. Practice safer sex. Practice safer drug use. Practice good personal hygiene, such as thorough handwashing. Hepatitis A and B are preventable, and hepatitis C is curable. For more information, see the CDC's viral hepatitis fact sheets.

Herpes is an STI that can cause sores on the genitals and/or mouth. An estimated one in six people in the U.S. has genital herpes, and there is no cure. Still, prescription medication can ease symptoms and lower the chances of passing the virus to others. Herpes can be painful but usually does not lead to serious health problems. For more information, see the CDC's herpes fact sheet.

HPV is the most common STI with an estimated 14 million new cases in the U.S. each year. There are more than 150 different types of HPV, and while some forms of HPV cause genital warts, many do not show any symptoms. Some forms can be severe and lead to cancer. The HPV vaccine protects against specific types associated with genital warts and cervical cancer. For more information, see the CDC's HPV fact sheet.

Trichomoniasis, sometimes called "trich" for short, often does not show any symptoms. An estimated 3.7 million people are living with trich in the U.S. Trich is usually not serious and can be cured in most cases. Once diagnosed, it is easily cured with antibiotics. For more information, see the CDC's trichomoniasis fact sheet.