Sexually Transmitted Infections: Prevention, Testing, and Treatment

Sexually transmitted infections (STIs; also known as sexually transmitted diseases or STDs) are common among young adults. There are an estimated 20 million new cases of STIs in the United States every year—half of those infections are in people under 25. 

There are two main types of STIs: bacterial and viral infections. Bacterial infections can be cured and include chlamydia, gonorrhea, and syphilis. Viral infections can be treated (but often not cured) and include the 4 Hs: hepatitis B, herpes, human immunodeficiency virus (HIV), and human papillomavirus (HPV). Another type of STI is parasitic (pubic lice, trichomoniasis). 

Most STIs do not have any symptoms—you can’t look at yourself or a sexual partner and know for sure whether you have an infection. The only way to know for sure is to get tested. See below for more information on STIs, including how to prevent them and how to test for them.

 

Chlamydia (bacterial)

How You Get It: Having oral, vaginal, or anal sex with someone who has chlamydia. Could also be transmitted from mother to a baby during childbirth.

Symptoms: Most people do not have symptoms. If symptoms are present, they may look like other infections. Symptoms include: abnormal discharge from the penis or vagina; painful urination; rectal discharge or itching.

Prevention: Not having oral, vaginal, or anal sex. Using condoms or other barrier methods correctly during every sexual act. Having sexual contact with only one person who is not infected and who is having sexual contact only with you.

Testing: A vaginal swab or urine sample can be used to test for chlamydia. If you are under 25 and sexually active with new sex partners, you should be tested for chlamydia at least once a year; you should be tested more often if you have increased risk. If you test positive for chlamydia, you should have repeat testing in 3 months.

Treatment: Antibiotics. It is important to take your medications the way your health care provider tells you. Do not engage in sexual activity until you’ve completed treatment. Your partner(s) may need treatment, too.

 

Gonorrhea (bacterial)

How You Get It: Having oral, vaginal, or anal sex with someone who has gonorrhea. Could also be transmitted from a mother to a baby during childbirth.

Symptoms: Most people do not have symptoms. If symptoms are present, they may look like other infections. Symptoms include: abnormal discharge from the penis or vagina; painful urination; rectal discharge or itching.

Prevention: Not having oral, vaginal, or anal sex. Using condoms or other barrier methods correctly during every sexual act. Having sexual contact with only one person who is not infected and who is having sexual contact only with you.

Testing: A vaginal swab or urine sample can be used to test for chlamydia. If you are under 25 and sexually active with new sex partners, you should be tested for gonorrhea at least once a year; you should be tested more often if you have increased risk.

Treatment: Antibiotics. It is important to take your medications the way your health care provider tells you. Do not engage in sexual activity until you’ve completed treatment. Your partner(s) may need treatment, too. Antibiotic strains of gonorrhea are becoming more common, making treatment harder, but not impossible.

 

Hepatitis B (viral)

How You Get It: Hepatitis B is transmitted through blood, semen, or certain other body fluids. It can be spread through sexual contact, sharing needles or syringes, or sharing personal items like a toothbrush or a razor.

Symptoms: Most people with hepatitis do not have any symptoms. If a person does have symptoms, they could take decades to develop. Symptoms can include: jaundice, fever, fatigue, dark urine, or joint pain, among other symptoms.

 

Prevention: There is a vaccine for hepatitis B that most people born in the U.S. get as a child. If you have not been vaccinated, talk to your health care provider about being vaccinated. To prevent hepatitis B, people should avoid contact with body fluids during sexual activity. Condoms can be used to reduce the risk, too. Do not share needles, syringes, or other works.

Testing: It is recommended that people who have not been vaccinated against hepatitis B and are high risk be tested. This includes: people with HIV, people with hepatitis C, people who were born in countries with high rates of hepatitis B. Talk to your health care provider to see if you should be tested for hepatitis B.

Treatment: There is no medication to treat acute (early) infection, but people with chronic (long-term) infection could be treated with antiviral drugs.

 

Herpes (viral)

How You Get It: Herpes is transmitted through oral, vaginal, and anal sex; it could also be passed through skin-to-skin contact in an area infected with herpes, including kissing. A person does not have to have a herpes sore present to transmit the virus.

Symptoms: Most people with herpes do not have symptoms, or symptoms are mild. If someone has symptoms, it may look like small bumps (blisters) at the site of infection. The blisters will break open and leave painful sores that last for a week or two.

Prevention: Not having oral, vaginal, or anal sex. Avoiding sexual activity with someone right before and during an outbreak. Limiting the number of sexual partners. Using condoms and other barrier methods may help to reduce the risk, but if a herpes infection is outside of the area covered by a condom or barrier, then it will provide less protection.

Testing: If someone has bumps or blisters, a health care provider may be able to diagnose herpes by looking at the symptoms. The provider could also take a sample from the bumps to send to a lab for confirmation. Routine testing for herpes is not recommended.

Treatment: There is no cure for herpes, but medications can treat the symptoms and reduce outbreaks.

 

Human Immunodeficiency Virus (HIV) (viral)

How You Get It: Through blood, semen, pre-ejaculate (pre-cum), rectal fluids, vaginal fluids, and breast milk. A person must have HIV in order to transmit it to other people. In the U.S., HIV is mainly spread through sexual contact (including vaginal and anal sex), as well as by sharing needles, syringes, or other “works” used when injecting drugs. It is possible for HIV to be transmitted during pregnancy, childbirth, or breastfeeding.

Symptoms: HIV weakens a person’s immune system by destroying important cells that fight viruses and infection. Most people do not have any symptoms, or the symptoms look like other infections. If a person becomes infected with HIV, they may experience flu-like symptoms within 2-4 weeks. Those symptoms will go away after a period of time. A person with HIV who is not receiving treatment may go 10 or more years before developing symptoms (although this is different for each person). At this point, the person’s immune system has been damaged by HIV and they may start developing symptoms that could lead to an AIDS diagnosis.Acquired immune deficiency syndrome (AIDS) is a clinical diagnosis usually made when someone’s immune system has been weakened by HIV. In order to be diagnosed with AIDS, a person must be infected with HIV, but not everyone with HIV has an AIDS diagnosis. Only a health care provider can make this diagnosis.

Prevention: Not having vaginal or anal sex. If you are sexually active, have sexual contact with only one person who is not infected and who is having sexual contact only with you. Use condoms and other barriers correctly and consistently from start to finish with each sexual encounter. Discuss with a potential partner about being tested for HIV before you have sex with each other. Do not share needles or other works.

Testing: Everyone 13-64 years old should get tested for HIV at least once. If you have certain risk factors, you should be tested more often. These include having unprotected vaginal or anal sex, having sex with someone who is HIV-positive, and/or sharing needles or syringes. Talk to your health care provider about how often you should be tested and available tests for HIV.

Treatment: There is no cure for HIV or AIDS, but there are medications that can lengthen a person’s life and decrease their risk for spreading the virus to other people. If you have HIV, it is important that you see a health care provider who specializes in treating the virus. It is also important that you take your medication as prescribed.

There are medications available for people who have been exposed to HIV or before exposure happens.

 

Human Papillomavirus (HPV) (viral)

How You Get It: Having oral, vaginal, or anal sex with someone who has HPV; it could also be passed through skin-to-skin contact in an area infected with HPV.

Symptoms: There are many strains of HPV—some can cause genital warts, some can cause changes to cervical cells that could lead to cervical cancer, and some can lead to other types of cancer. Most people do not have symptoms. If someone is infected with HPV that causes genital warts.

Prevention: Not having oral, vaginal, or anal sex. Limiting the number of sexual partners. Using condoms and other barrier methods may help to reduce the risk for HPV. Vaccines are available for males and females to prevent several strains of HPV. It is recommended that people 11 to 26 years old be vaccinated. The vaccines are most effective if given before someone is sexually active. Make sure to get all of the vaccines in the series (usually 3 shots) to increase effectiveness.

Testing: A health care provider can usually diagnose genital warts by looking at the genital area. There is an HPV test available for women over 30 years old. It is not recommended for women younger than 30. An HPV test can be done in conjunction with a Pap test. For more information on Pap testing, click here.

Treatment: In most cases, HPV will go away on its own. For genital warts, they could be treated by a health care provider. For information on treating changes to the cervix, visit this section.

Almost 59% of students reported receiving the HPV vaccine. The HPV vaccine may prevent some of the most common strains of HPV and may prevent HPV-associated cancers and genital warts.

 

Pubic Lice (parasite)

How You Get It: Pubic lice are spread through sexual contact. While rare, it is possible for pubic lice to be spread through close personal contact that is not sexual or by sharing clothing, beds, bed linens, or towels. Pubic lice are not spread through animals or toilet seats.

Symptoms: The most common symptom is itching in the genital area. Depending on the stage, a person might see eggs or crawling lice.

Prevention: Avoid contact with another person’s genital area. If you are sexually active, have sexual contact with only one person who is not infected and who is having sexual contact only with you.

Testing: A diagnosis is usually made by seeing crawling lice or eggs. If a person thinks they have pubic lice, they should see a health care provider to be tested for other sexually transmitted infections (STIs).

Treatment: Pubic lice can be treated with over-the-counter lotions and creams. A health care provider can write a prescription for other lice-killing medicines. It is important to wash clothes, bedding, and towels with hot water and dry them using the hot cycle of the dryer.

 

Syphilis (bacterial)

How You Get It: Having oral, vaginal, or anal sex with someone who has syphilis. Could also be transmitted from a mother to a baby during childbirth. There are 4 stages of syphilis: primary, secondary, latent, and tertiary. A person can spread the infection to others if they are in the primary or secondary stage.

Symptoms: Symptoms are broken down by stage:

  • Primary: 1 or more sores at the site of infection. The sore is usually painless and will go away on its own. If it goes away, a person still has syphilis and can still infect others.
  • Secondary: usually a skin rash or sores in the mouth, vagina, or anus. Could also include fever, fatigue, or swollen lymph nodes. The rash can go away on its own, but a person can still transmit the infection to others.
  • Latent: Usually a person has no symptoms during this time. Someone is often not infectious during this stage.
  • Tertiary: This stage is rare, but could impact vital organs, such as the heart and brain

Prevention: Avoid contact with another person’s genital area. If you are sexually active, have sexual contact with only one person who is not infected and who is having sexual contact only with you. Condoms and other barrier methods may help to reduce the risk; they should be used consistently and correctly.

Testing: A blood test is used to test for syphilis; a finger stick or a blood draw from a vein could be used to get a sample. Anyone who is at an increased risk for syphilis should be tested. This could include people with multiple sexual partners and people living with HIV/AIDS. Talk to your health care provider to see if you should be tested.

Treatment: Antibiotics can be given at any stage of infection, but antibiotics cannot undo any long-term effects caused by syphilis, such as organ damage. It is important to take your medications the way your health care provider tells you. Do not engage in sexual activity until you’ve completed treatment. Your partner(s) may need treatment, too.

 

Trichomoniasis (parasite)

How You Get It: Most often spread through vaginal sex, including penis-vagina and vagina-vagina sex.

Symptoms: Most people do not have symptoms. If someone does have symptoms, they could include genital itching, burning with urination, or unusual discharge.

Prevention: Avoid contact with another person’s genital area. If you are sexually active, have sexual contact with only one person who is not infected and who is having sexual contact only with you. Condoms can help to reduce the risk; they should be used consistently and correctly.

Testing: A health care provider can collect a sample through a swab of the vagina or penis, or through a urine sample.

Treatment: Medications can treat trichomoniasis. It is important to take your medications the way your health care provider tells you. Do not engage in sexual activity until you’ve completed treatment. Your partner(s)may need treatment, too.

STIs are not spread through toilet seats, swimming, sharing utensils, hugging, or holding hands.

Find an STI testing facility near you: https://gettested.cdc.gov/.

Pap Testing

A Pap test (or Pap smear) is used to look for possible abnormal cervical cells. Abnormal cells could lead to cervical cancer, although not always. A Pap test does not test for HPV; there is an HPV test that is used, often starting at age 30 or older, for people with a cervix, to test for HPV. A Pap test is not used to test for other STIs.

To do a Pap test, a health care provider will insert a tool called a speculum into the vagina to open the walls of the vagina and look at the cervix. A soft brush is used to collect cervical cells for testing.

Pap Testing Recommendations

  • Pap testing is not recommended for people under age 21. This is because the body does a good job of clearing HPV infections on its own.
  • People with a cervix who are 21-29 years old should get a Pap test every three years.
  • People with a cervix who are 30-65 years old should get:
    • A Pap test every three years, or
    • An HPV test every five years, or
    • A Pap and HPV test together every five years

Even if you have received the HPV vaccine, you should still get regular Pap tests following these recommendations.

If you have an abnormal Pap test, your health care provider may recommend that you get screened more often. Depending on the type of abnormal Pap test you receive, your clinician may recommend other testing called colposcopy. During a colposcopy, your health care provider uses an instrument called a colposcope to look closer at the abnormal cells. Your clinician may take a sample of those cells (a biopsy) and send it to the lab to determine the best steps for treatment.

HIV Testing

There are several types of HIV tests available. Most tests screen for HIV antibodies, not the virus itself. No test can detect HIV immediately after infection. The time between when a person has been infected with HIV and when a test can tell if someone has HIV is called the window period. The window period varies from test to test. Because most tests use HIV antibodies to detect infection, the window period for antibody tests range from 18-90 days. This means that a person would need to wait 18-90 days after possible exposure with HIV to be tested for HIV. If a person engages in activities that could put them at risk for infection (such as having sex without a condom or sharing needles) within that window period, then the window period resets. If a person is tested for HIV during the window period and their result is negative, it does not necessarily mean that they do not have HIV. It is important for that person to be tested again after 18-90 days to ensure that they are HIV-negative.

It is possible to test for HIV through blood and through an oral fluid test. With a blood test, a person could have blood drawn from a vein or provide a finger-stick to collect a blood sample. With an oral fluid test, a special swab is used to collect an oral fluid sample. Rapid blood and oral fluid tests are available, with results given in 20-30 minutes or less.

If someone has an HIV antibody test and the result is positive, a confirmatory test will need to be done. If you have blood drawn in a lab, they are often able to do a confirmatory test on that sample. If you have a rapid blood or oral fluid test, you will be sent to a health care provider for follow up testing. There is a chance that the result could be a false positive, which is why confirmatory testing is needed.

PrEP/PEP for HIV Prevention

PrEP

Pre-exposure prophylaxis (PrEP) is when people who are at high-risk for HIV take medications daily to reduce their chances of infection. It is highly effective if taken as prescribed. PrEP is recommended for people who are HIV-negative and are in an ongoing sexual relationship with someone who is HIV-positive, as well as for people who inject drugs. Not all insurance covers the cost of PrEP, so people often have to pay for it out of pocket. Talk to your health care provider to learn more about PrEP.

PEP

Post-exposure prophylaxis (PEP) is when people take medications to reduce the risk of HIV infection after they have been exposed to HIV. PEP should only be used in emergency situations and should be started within 72 hours of possible exposure to HIV. PEP can be used in the following situations:

  • Someone has been exposed to HIV during sex (such as if the condom broke)
  • Someone shared needles or other works with someone with HIV
  • Someone is sexually assaulted

PEP should not take the place of regular HIV prevention methods, such as PrEP, condom/barrier use, and using your own clean needles to inject drugs. Talk to your health care provider to learn more about PEP.

Learn more about PrEP and PEP here.