What are sexually transmitted infections (STIs)?

Sexually transmitted infections (STIs) are infectious diseases spread through sexual contact. About 50 out of 100 new STIs happen in people ages 15 to 24.

Protecting your teen from STIs

The best way to prevent your teen from contracting an STI is to advise them to not have any type of sexual contact with another person. But if they decide to be sexually active, or are currently sexually active, there are several safety measures to follow. These are advised by experts to help reduce your teen's risk of getting an STI. They include:

• Have a mutually monogamous sexual relationship with an uninfected partner.

• Use (consistently and correctly) a male latex or female polyurethane condom, even for oral sex.

• Reduce the chance of getting an HIV infection by preventing and controlling other STIs. Having another STI makes it easier to get infected with HIV.

• Strongly think about taking HIV prevention treatments, including:

  • PEP (post-exposure prophylaxis). Taking medicines to prevent HIV within 72 hours after a risky exposure.

  • PrEP (pre-exposure prophylaxis). Taking medicine regularly to prevent HIV infection from possible future exposures during unsafe sex.

• If you're going to have sex with someone who is HIV-positive, be very sure the other person is taking their HIV medicines and that their viral load is completely under control (undetectable).

• Delay having sexual relationships as long as possible. The younger a person is when they start to have sex for the first time, the more susceptible they are to getting an STI.

• Have regular checkups for HIV and STIs.

• Learn the symptoms of STIs. Get medical help as soon as possible if you have any symptom.

• Don't have sex during menstruation.

• Don't have anal intercourse.

• Don't use a male latex condom and topical microbicides together. The topical agent can break down the condom, making it less effective.

• Don't douche.

What should my teen do if diagnosed with an STI?

• Have your teen start treatment right away. They should take the full course of medicines and follow their healthcare provider's advice.

• Tell all recent sex partners and urge them to get healthcare checkups. If your teen doesn't want to do this personally, your local health department can help. 

• Your teen shouldn't have sex while being treated for an STI, and generally not for at least 1week after. If your teen's partner also needs treatment, they should wait until their treatment is done as well.

• Your teen should have a follow-up test to be sure the STI has been successfully treated.

What are some common types of STIs?

Many STIs have been identified. Common types of STIs include:

• HIV. HIV, the virus that causes AIDS, destroys the body's ability to fight off infection. It is spread by unprotected sex with an infected person. It's also spread by contact with infected blood or contaminated needles. People with advanced HIV infection are very susceptible to many life-threatening diseases and to certain forms of cancer.

• HPV. Human papillomavirus (HPV) is a common STI that can cause genital warts. These can happen on the inside or outside parts of the genitals and rectum. They may spread to the nearby skin or to a sex partner. HPV infection doesn't always cause warts. So you may not know you're infected. Women with an HPV infection have a higher risk of cervical and anal cancer. Men with HPV infection can get cancer of the penis or anal area. Regular cervical Pap tests can find HPV infection, as well as abnormal cervical cells. A Pap test can also be done of the anus to look for HPV infection and abnormal cells. An HPV vaccine is available to help prevent cervical cancer and genital warts. This vaccine is advised starting at age 11. But it can be given as young as age 9. Discuss this with your child's healthcare provider. There is treatment for genital warts. These sometimes go away on their own. But the virus remains and warts can come back. Some types of HPV can also cause warts (called common warts) on other body parts such as the hands. But these don't generally cause health problems.

• Chlamydia. Chlamydial infections, the most common of all STIs, can affect both men and women. They may cause an abnormal genital discharge, burning with urination, and rectal discharge and bleeding. In women, untreated chlamydial infection may lead to pelvic inflammatory disease (PID). This is an infection of the uterus, fallopian tubes, and other reproductive organs. It causes symptoms such as lower belly pain. Chlamydial infections can be treated with antibiotics. Unfortunately, many people with chlamydial infection have few or no symptoms. The most common and serious complications happen in women and include pelvic inflammatory disease, tubal (ectopic) pregnancy, and trouble having children (infertility). Men may have urinary symptoms or no symptoms at all.

• Gonorrhea. Gonorrhea causes a discharge from the vagina, penis, or rectum. It also causes painful or difficult urination or bowel movements. The most common and serious complications happen in women. These include pelvic inflammatory disease, ectopic pregnancy, and trouble having children (infertility). Gonorrhea infections can be treated with antibiotics.

• Genital herpes. Genital herpes infections are caused by the herpes simplex virus (HSV). Symptoms may include painful blisters or open sores in the genital or rectal area. First there may be a tingling or burning feeling in the area. The herpes sores often go away in a few weeks. But the virus stays in the body. And the sores may come back from time to time. There is no cure for HSV. But there are antiviral medicines that can shorten an outbreak, reduce symptoms, help to prevent recurrences, and decrease the chance of passing the virus on to others.

• Syphilis. The first symptom of syphilis is a painless open sore. It is often seen on the penis, in the vagina, in the mouth, or on the skin around these areas. Untreated syphilis may go on to more advanced stages. This includes a short-term rash. Over time, the heart and central nervous system may be seriously affected. Syphilis infections can be treated with antibiotic therapy.

• Pelvic inflammatory disease (PID). PID is a serious complication women can get from some STIs, such as chlamydia and gonorrhea. PID is an infection of the uterus, fallopian tubes, and other reproductive organs. It can cause lower belly pain. Later on it can cause problems having children.

Other diseases that may be sexually transmitted include:

• Bacterial vaginosis

• Chancroid

• Cytomegalovirus infections

• Granuloma inguinale (donovanosis)

• Lymphogranuloma venereum

• Molluscum contagiosum

• Pubic lice

• Scabies

• Trichomoniasis

• Oral ulcers (oral sex can result in ulcers from gonorrhea or herpes)

Facts about STIs and teens

1. STIs affect people of all backgrounds and income levels. But nearly 50 out of 100 STI cases in the U.S. happen in people younger than age 25.

2. STIs are on the rise, possibly due to more sexually active people who have multiple sex partners during their lives.

3. Many STIs cause no symptoms at first. And many STI symptoms may be confused with those of other diseases not spread by sex, especially in women. Even symptomless STIs can be contagious and can later cause long-term (chronic) or serious health problems. 

4. Women suffer more frequent and severe symptoms from STIs:

   • Some STIs can spread into the uterus and fallopian tubes and cause PID. This can lead to both infertility and ectopic (tubal) pregnancy.

   • Some strains of HPV infection in women may also be linked to cervical cancer. In both women and men, these strains may cause anal, head, and neck cancer.

   • STIs can be passed from a mother to her baby before or during birth. Some newborn infections may be successfully treated. Others may cause a baby to be permanently disabled or even die.

5. Once diagnosed, many STIs can be successfully treated. Some STIs, such as herpes, can't be completely cured and may happen again. But each recurrence can be prevented or treated.

6. Key ways to prevent transmission of HIV infection include PEP within 72 hours of exposure and PrEP to prevent transmission if there is ongoing risk. Also make sure that HIV-positive partners are under treatment and have their virus under control.