STIs—A to Z

Sexually transmitted infections (STIs), affect people of all ages, backgrounds, and from all walks of life. As the name suggests, STIs are usually are passed on through sex—vaginal, oral or anal.

Some STIs can be spread through any contact between the penis, vagina, mouth or anus, even if there is no penetration. For example, genital herpes and human papillomavirus (HPV) can be spread through direct skin-to-skin contact—no penetration necessary. Some STIs can be spread in other ways also. For example, HIV and hepatitis B are also spread through sharing needles for injecting drugs or medicines.Knowing about STIs and how to get tested and treated is essential to taking care of your sexual health.

STIs are very common

Anyone who is sexually active can get an STI. In the U.S. alone there are approximately 20 million new cases each year. About half of these cases are in young people ages 15-24 years.

Most STIs have no symptoms

The fact that most STIs have no noticeable symptoms is one reason why the term STI is now more commonly used—a person can have an infection but no signs on any disease. So symptoms (or the lack or symptoms) is no way to judge whether you, or someone else, has an STI. The only way to know is to get tested.

Without treatment, STIs can cause severe health problems

Take chlamydia as an example. This STI is easily treated and cured with antibiotics. But if chlamydia goes untreated in a person with a uterus, it can lead to a more severe condition called pelvic inflammatory disease (PID). The uterus, fallopian tubes, and ovaries can all be damaged by untreated infection and this damage can harm future fertility (the ability to have children). In the U.S., PID is the leading cause of infertility in women.

Syphilis is another example. In the early stages of infection, syphilis can be treated and cured with antibiotics. But left untreated, syphilis can cause can cause serious, irreversibly damage and even death. Syphilis during pregnancy is also serious issue. It can cause miscarriage, stillbirth, and infant death. Babies born with syphilis can face lifelong medical issues.

All STIs are treatable

While not all STIs can be cured, they can all be treated. For example, while HIV infection can’t be cured, HIV treatment (antiretroviral therapy or ART) reduces the amount of HIV in your body and helps you stay healthy. It also helps prevent the virus from being passed on to sexual partners. Health problems can happen when STI are untreated, so getting tested regularly is important.

There are more testing options than ever before

If you have a regular health care provider, you can always ask them about STI testing. If you don’t already have a provider, you can search for a clinic that offers free or low cost testing near you. And now you can also test from the privacy of your own home, with tests conveniently delivered to you. Learn more about testing here.

A provider talks to a patient

Chlamydia is a Common and Curable Infection

Chlamydia is the most common reported bacterial STI in the U.S. It is most common in younger people—it is estimated that 1 in 20 sexually active young women aged 14-24 years has chlamydia.
Doxy-PEP works

New Studies Add to Evidence that Doxy PEP Works for STI Prevention

New studies add to our evidence that doxy PEP works to prevent bacterial STIs among transgender women and men who have sex with men.
A man speaks with a health care provider

Two Studies Show Doxy PEP is a Winning Strategy

Two studies published in this month’s JAMA Internal Medicine offer encouraging findings about the use of doxy PEP.
Many hands are placed on a pregnant person's belly

The Impact of STIs on Fertility

Infertility can stem from factors affecting both men and women. Sometimes, these are related to sexually transmitted infections (STIs). Learn more out the impact of STIs on fertility.
At-home test for chlamydia, gonorrhea, and trich

FDA Approves a New At-Home Test for Three Common STIs

The FDA just approved a new, fully at-home test for chlamydia, gonorrhea, and trichomoniasis. The tests, which is only for women, will be available without a prescription. Users can collect their own sample and have results in less than 30 minutes.
The State of STIs 2024

Latest Data Shows that Chlamydia, Gonorrhea, and Syphilis Rates are Dropping

The CDC just released STI Surveillance Data for 2024 that show cases of chlamydia, gonorrhea, and syphilis are slowly declining.
A prescription bag

Are Patients Not Following Through with STI Treatment?

About 1.6 million cases of chlamydia and 600,000 cases of gonorrhea are diagnosed in the United Sates each year. A new study suggests that these patients may not be following through with STI treatment or getting the right antibiotics.
Gonorrhea

Learn About Gonorrhea and How to Prevent It

Gonorrhea (also known as “the clap”) is an infection caused by the bacteria Neisseria gonorrhoeae. It is passed on during vaginal, anal, and oral sex (performing or receiving).
Doxy-PEP works

New Studies Add to Evidence that Doxy PEP Works for STI Prevention

New studies add to our evidence that doxy PEP works to prevent bacterial STIs among transgender women and men who have sex with men.
A man speaks with a health care provider

Two Studies Show Doxy PEP is a Winning Strategy

Two studies published in this month’s JAMA Internal Medicine offer encouraging findings about the use of doxy PEP.
Many hands are placed on a pregnant person's belly

The Impact of STIs on Fertility

Infertility can stem from factors affecting both men and women. Sometimes, these are related to sexually transmitted infections (STIs). Learn more out the impact of STIs on fertility.
At-home test for chlamydia, gonorrhea, and trich

FDA Approves a New At-Home Test for Three Common STIs

The FDA just approved a new, fully at-home test for chlamydia, gonorrhea, and trichomoniasis. The tests, which is only for women, will be available without a prescription. Users can collect their own sample and have results in less than 30 minutes.
The State of STIs 2024

Latest Data Shows that Chlamydia, Gonorrhea, and Syphilis Rates are Dropping

The CDC just released STI Surveillance Data for 2024 that show cases of chlamydia, gonorrhea, and syphilis are slowly declining.
Historical poster on gonorrhea

Antibiotic-Resistant Gonorrhea is On the Rise Globally 

A new report from the World Health Organization (WHO) warns of rising levels of antibiotic-resistant gonorrhea. The data comes from reported cases of gonorrhea in 12 countries across five WHO regions.
A newborn

Why It’s Important to Vaccinate Newborns for Hepatitis B

Experts say that vaccinating newborns against hepatitis B is one of the most important things we do to protect infants.
Hepatitis C

The 5 Main Types of Hepatitis (including 2 you can vaccinated against)

Hepatitis is an inflammation of the liver that can be caused by a group of viruses—hepatitis A, B, C, D and E. When hepatitis viruses damage liver cells, scar tissue is formed and those cells can no longer function.
An infant with a bandage where a vaccine was administered

ACIP Changes Hepatitis B Vaccination Gudiance

A committee that advises the Centers for Disease Control and Prevention (CDC) made an alarming change to the recommendations for the hepatitis B vaccine that will leave some infants unprotected.
Hepatitis C

Cure Rates for Hepatitis C “Jarringly Low”

According to new data from the Centers for Disease Control and Prevention (CDC), only one in three adults in the U.S. infected with hepatitis C have been cured despite the introduction of direct-acting antivirals almost 10 years ago.
Doctor showing something to a patient

Fast facts about HSV (Herpes Simplex Virus)

Herpes is a very common viral infection caused by herpes simplex virus (HSV). I can cause sores on the mouth or face or in the genital area. Herpes cannot be cured, but it can be treated.
A microphone and a pair of headphones for a podcast conversation with Terri Warren

Diagnosing and Managing Herpes: A Two-Part Conversation with Terri Warren

In this two-part episode of ASHA's Sex+Health podcast, Terri Warren, RN, ANP explains many approaches to diagnosing herpes as well as strategies to effectively manage herpes in a relationship and deal with the emotional aspects of the diagnosis.
STI National Plan

HHS Recognizes Herpes as a Priority in the STI National Plan

The STI National Plan has now been amended to add genital herpes as a priority.
Doctor holding a sign that says herpes

ASHA Survey Shows Many Herpes Patients Diagnosed Incorrectly

Think you can tell that a rash or sore is a genital herpes infection just by looking at it? If you said “no,” you’re right. You can’t. And neither can your health care provider.
Five things to know about herpes

5 Things You Should Know about Herpes

ASHA answers many questions from the public about STIs, including about herpes. Here we offer five things to know about how to manage this common infection.
Managing Herpes

Managing Herpes: The Science, The Facts, The Feelings

Managing Herpes: The Science, The Facts, The Feelings helps take the mystery out of herpes, explaining everything from diagnosis and treatment, to symptom management, to herpes and pregnancy.
USPSTF Logo

Task Force Decides Against Routine Herpes Screening

The U.S. Preventative Service Task Force (USPSTF) has advised against routine herpes screening in adolescents, adults, and pregnant women.
HIV Affects Everyone

Fast Facts about HIV

HIV stands for human immunodeficiency virus. Learn the basics about HIV prevention, testing, and treatment.
Vampire facials

Vampire Facials Confirmed as Cause of At Least Three HIV Infections 

A joint investigation by the CDC and the New Mexico Health Department has confirmed that an unlicensed medi-spa is responsible for at least three cases of HIV from vampire facials.
National Gay Men's HIV/AIDS Awareness Day

Living with HIV

Life continues after becoming HIV positive. Thanks to new treatments, many people with HIV are living long, healthy lives.
PrEP in a pill or a shot

Should I take PrEP?

PrEP stands for pre-exposure prophylaxis. The word prophylaxis means to prevent or control the spread of an infection or disease. The goal of PrEP is to prevent HIV infection from taking hold if you are exposed to the virus.
Free HIV and STI Testing

HIV Testing

The only way to tell you have HIV is get tested. HIV testing is recommended at least once for everyone, and may be recommended more often for some. Testing can be quick, easy and confidential.
A pregnant woman looks at a sonogram

HIV and Pregnancy—Take Steps to Protect Your and Your Baby

There is a lot to think about when you want to have a baby or when a baby is on the way. One important step is to learn about HIV. Knowing whether you have HIV can help you decide how to protect your baby.
HIV Treatment

People with Low Viral Loads Have Almost Zero Chance of Transmitting HIV Through Sex

A new meta-analysis of eight published studies found that the risk of sexual transmission of HIV is almost zero in people with low viral loads.
An image of HPV

Human Papillomavirus (HPV)

Human papillomavirus, or HPV, is very common. Some types of HPV can cause genital warts and other types can cause cancer, including cancer of the cervix, vulva, vagina, penis or anus, as well as cancer in the back of the throat.
Early HPV vaccination saves lives

Even More Evidence for the Value of Early HPV Vaccination

An exciting study in Scotland found no cases of invasive cervical cancer in young women who had gotten the HPV vaccine by the time they were 14. The study offers more evidence for the value of early HPV vaccination.
A couple sits with their heads together, with questions about HPV and relationships

HPV and Relationships—Answers to Your Questions

After a diagnosis, it's normal to have questions about HPV and relationships: What does this mean for our health? Did someone cheat? Should we stop having sex?
A young person wearing a mask gets vaccinated

HPV Vaccination Rates Among Teens Not Going Up

For the second year in a row, HPV vaccination rates among teens have not gone up according to the Centers for Disease Control and Prevention (CDC).
A uterus

New Option for Cervical Cancer Screening — Self Collected Samples

The FDA recently approved HPV testing using self-collected samples. Experts hope allowing people to collect their own samples will increase screening rates.
Human papillomavirus or HPV

Genital Warts

Genital warts are caused by human papillomavirus (HPV). The types of HPV that cause genital warts are usually spread by direct skin-to-skin contact during vaginal, anal, or possibly oral sex with someone who has this infection.
No speculum needed for HPV testing with self-collection

What You Need to Know About HPV Testing with Self-Collection

There’s a new way to screen for cervical cancer—no pelvic exam, stirrups, or speculum involved. Learn about HPV testing with self-collection.
Syphilis can be cured

Understanding Syphilis and How to Prevent It

Syphilis can be treated more easily if it is caught early. But undiagnosed and untreated syphilis can be dangerous. It can cause irreversible health damage and even death.
A pregnant woman holding her belly

Drug Shortage Means Pregnant Patients Get Delayed Care

As rates of congenital syphilis skyrocket, a severe shortage of the only antibiotic approved to treat syphilis in pregnant women is delaying care for pregnant patients.
A woman holds her pregnant belly
The number of babies born with syphilis in the United States is increasing at an alarming rate. There were over 10 times as many babies born with syphilis in 2022 than in 2012. Learn about syphilis and pregnancy.
Doxy-PEP works

New Studies Add to Evidence that Doxy PEP Works for STI Prevention

New studies add to our evidence that doxy PEP works to prevent bacterial STIs among transgender women and men who have sex with men.
An infant is in an incubator in the NICU

Understanding the Social Factors Associated with Congenital Syphilis

Public health experts have said that every case of congenital syphilis is a failure of STI screening and prenatal care. A new study looked more closely at cases to see what factors in a pregnant person’s life were most associated with congenital syphilis.
Finger prick blood test for an at-home syphilis test 

FDA Approves First At-Home Syphilis Test 

The FDA recently approved an at-home syphilis test that can provide initial results in just 15-minutes. Syphilis has been surging in recent years with the number of cases rising 80% between 2018 and 2022 alone.
Syphilis Testing in Pregnancy

New Guidelines on Syphilis Testing in Pregnancy

The American College of Obstetricians and Gynecologists released new guidelines for syphilis testing in pregnancy, recommending that all pregnant people be screened for syphilis three times during pregnancy.
Trichomoniasis

Trichomoniasis (a.k.a. “Trich)

With roughly two million cases in the U.S., trichomoniasis (“trich”) is the most common STI you’ve never heard of. Learn more about this common STI in our four-part expert series.
Healthy vaginas

Vaginal Health

What keeps a vagina healthy? Like many things in life, it’s all about balance. What's important is to know what's normal and when things may be off—and when to seek care for your vaginal health.
At-home test for chlamydia, gonorrhea, and trich

FDA Approves a New At-Home Test for Three Common STIs

The FDA just approved a new, fully at-home test for chlamydia, gonorrhea, and trichomoniasis. The tests, which is only for women, will be available without a prescription. Users can collect their own sample and have results in less than 30 minutes.
NGU

NGU, or Nongonoccocal Urethritis

Nongonococcal urethritis—or NGU—is an infection of the urethra caused by germs other than gonorrhea. The most common cause is chlamydia.
Mgen

MGen: The STI You’ve (Probably) Never Heard Of

Mycoplasma genitalium, or Mgen, was first identified in 1981. It is a bacterium that can infect the reproductive tract and is passed on through sexual contact.
Molluscum A sample is viewed under a microscope

Molluscum Contagiosum

Molluscum contagiosum is a skin disease caused by the molluscum contagiosum virus (MCV) Once a disease primarily of children, molluscum has evolved to become a sexually transmitted infection in adults.
A person with lesions on their abdomen from scabies

Scabies

Scabies is an infestation of the top layer of skin caused by the parasite. Scabies are passed on through close physical contact. Transmission is more likely when partners spend the night together than during a brief sexual encounter.
Pubic lice or crabs

Crabs (a.k.a. Pubic Lice) usually don’t cause anything more than discomfort and inconvenience

Pubic lice, also known as crabs, are small parasites that are usually found on the pubic hair. Symptoms of crabs can be bothersome, but in general crabs don't cause anything more than discomfort and inconvenience.