Sexually Transmitted Diseases (STD) / Sexually Transmitted Infections (STI)

What is a sexually transmitted disease?

A sexually transmitted infection or STI (commonly referred to as a sexually transmitted disease, or STD), is any infection that is passed from person to person through sexual contact. There are dozens of different types of STDs but the most common ones—and the ones we're seeing a dramatic increase in, according to the Centers for Disease Control—are:

  • Chlamydia
  • Gonorrhea
  • Syphilis (primary and secondary)
  • Congenital syphilis (affecting newborns)

Other common STDs include genital herpes, which is caused by herpes simplex virus type 1 (HSV-1) or 2 (HSV-2). The CDC states that genital herpes affects more than one in every six people between 14 and 49 years old in the United States.

Human papillomavirus (HPV) is another STD, which is a virus that can cause cervical, anal and throat cancers. It is predictable that any sexually active person is likely to get HPV at some point in their lives—unless they get the HPV vaccine.

Having any kind of STD also puts you more at risk for HIV infection. This is because the kinds of sexual behavior that puts you at risk for getting an STD is the same type of behavior that puts you at greater risk for becoming infected with HIV. This may include:

  • Having anal, oral or vaginal sex without a condom
  • Having multiple sex partners
  • Having anonymous sex partners
  • Engaging in sexual activity while under the influence of drugs or alcohol (leading to greater risk-taking behavior)

Certain types of STDs, such as syphilis, gonorrhea and herpes, also make you particularly vulnerable to HIV. Any break in the skin from an open sore, for example, may allow easier transmission of HIV infection. Find out more facts on STDs and HIV.

How do you get an STD?

Although any sexually involved person can get an STD, women are affected differently than men. Some of the symptoms of STDs, such as vaginal itching or discharge, may seem like other conditions women are familiar with, such as yeast infections, and they may not realize they're infected.

In many cases—and for people of all genders—there are no symptoms or very mild symptoms. Therefore, treatable STDs get transmitted unknowingly, and may go undetected for months or years.

An STD is most often transmitted through "sexual contact," which refers to vaginal, anal or oral sex, but you can also be infected through direct genital or skin-to-skin contact. The sources of STIs are bacterium as well as viruses and parasites. These can grow inside or on the body, causing a wide range of symptoms.


How you get chlamydia

Unprotected oral, vaginal, anal sex with a person who's been infected; chlamydia can pass to baby during childbirth. Symptoms (if any) include:


  • Abnormal vaginal discharge
  • Painful intercourse
  • Burning sensation during urination


  • Burning sensation during urination
  • Itching or burning sensation around opening of penis

Genital herpes

How you get genital herpes

Unprotected oral, vaginal, anal sex with a person who's been infected; herpes can pass to baby during childbirth. Symptoms can range from multiple painful sores to one single sore. Herpes is painful when a breakout occurs. Visible symptoms are sores near the area where the virus was contracted, but the virus can spread even when there are no sores.


How you get gonorrhea

Unprotected oral, vaginal, anal sex with a person who's been infected; gonorrhea can pass to baby during childbirth. Symptoms (if any) include:


  • Bleeding between periods
  • Pain when urinating
  • Increased vaginal discharge
  • Pelvic inflammatory disease (if untreated)


  • Discharge from penis
  • Pain when urinating
  • Testicle and prostate problems (if untreated)


How you get HIV

Through blood or semen from unprotected vaginal or anal sex or through sharing of needles when using injected drugs. HIV can be transmitted from mother to baby at any time during pregnancy, labor and delivery, and during breastfeeding. When you are first infected with HIV, you may experience:
  • Flu-like symptoms
  • Swollen glands

This is usually within the first few weeks. Other more severe symptoms may not show up for many months or years—which is why regular STD testing is so important. Just ask your primary care providerfamily medicine doctorOB/GYN, or LGBTQ Inclusive Care provider.


How you get syphilis

Unprotected oral, vaginal, anal sex with a person who's been infected; syphilis can pass to baby during pregnancy or childbirth. Symptoms include:

All genders

  • Small, painless sores
  • Nolin-itchy skin rash that is often on hands and feet
  • Swelling in lymph nodes
  • Or no symptoms at all

In pregnant women, syphilis can cause complications such as premature birth, birth defects, and even the loss of the fetus.

Viral hepatitis

How you get viral hepatitis

Hepatitis is spread in a variety of ways:

HEPATITIS A – when someone ingests even a microscopic amount of fecal matter on food, drink or object touched by a person who's been infected. People most at risk are:

  • People who use drugs (injection as well as noninjection)
  • People who travel frequently, move around often, and live in different locations
  • Anyone who participates in anal sex
  • Recently incarcerated people or those currently incarcerated
  • People with cirrhosis, hepatitis B or C, or chronic liver disease

HEPATITIS B – when the blood, semen or other type of fluid of a person who's been infected enters the body of someone who is not infected. It can also be transmitted:

  • To a newborn by an infected mother
  • In a health care facility (outbreaks)
  • By sharing needles, syringes, medical equipment
  • Using the toothbrush or razor of a person who's been infected
  • By having sex with a person who's been infected

HEPATITIS C – when blood from a person who's been infected even in microscopic amounts gets into the body of someone who is not infected. It is rare for hepatitis C to be transmitted via sexual contact. Transmission happens when:

  • Contaminated needles or syringes are shared (drug use)
  • A baby is born to an infected mother
  • Health care facilities have poor infection control

Treatable STDs and how to prevent them

It's easier to prevent an STD than to have to treat one later. Here's how:

Abstinence is the only absolute way to avoid getting a sexually transmitted infection.

Abstinence means you avoid all sexual contact and there is no exchange of body fluids vaginally, orally or anally. Many young people do in fact choose to remain abstinent. This choice may not necessarily reflect religious beliefs or ideals, but a shift in mindset about healthy sexual behavior before committed partnership or marriage.

Vaccination helps prevent HPV and hepatitis A and B.

The HPV vaccine is available for children as young as nine years old and is often recommended for adolescents starting around age 11 or 12. The current recommendation is for all teen girls and young women through age 26 and all teen boys and young men through age 45 to receive the HPV vaccine.

You should get the hepatitis B vaccine if you did not receive it when you were younger. Keep in mind that vaccination does not prevent any other STDs.

Limit the number of sexual partners you have.

The more people you have sexual contact with the more likely you are to have a sexually transmitted infection—and vice versa. If you are involved with fewer partners, your chances of contracted an STI are less. But just because you have fewer sexual partners doesn't mean you're not at risk. You must still take precautions. Use condoms. Avoid risky behaviors, such as having partners you don't know, having sex while under the influence of drugs or alcohol, or trading sex for money or another commodity.

Agree to be in a mutually monogamous relationship with your partner.

When both of you are committed to being sexually involved only with each other, you are no longer putting each other at risk for STDs. However, you need to first find out if either of you is carrying an STD. This is time for open communication and perhaps even a trip to the doctor's office or clinic together. Remember, just about every sexually active person is likely to get HPV during their lifetime—let alone be vulnerable to all the other STDs out there—so there is nothing to blame each other about if one partner or both have a sexually transmitted infection. You can get treated at the same time and avoid reinfection.

Use condoms consistently and effectively.

Latex condoms are very effective in preventing STIs when having vaginal, anal or oral sex. Be informed about how to use them correctly to ensure they don't break or leak.

Getting screened for treatable STDs

Don't be afraid to find out whether or not you have a sexually transmitted infection. It's important to know now if you do so that you don't infect your partner(s) or perhaps experience relief if you don't have one.

Get the facts first. Get screened. It all starts by talking with your doctor.

Find a primary care physician you trust.

For young women, there may be additional tests you'll need to request of your gynecologist that are not part of your routine gynecological exam or Pap smear.

The current recommendation is that the following people be screened for STDs:

  • Anyone age 13 to 64 be tested at least once for HIV
  • Sexually active women under 25 tested for gonorrhea and chlamydia each year
  • Women over 25 at higher risk such as multiple sex partners or partner infected with STD, tested for gonorrhea and chlamydia each year
  • Pregnant women tested for syphilis, HIV and hepatitis B, beginning early in pregnancy
  • Pregnant women who are at-risk, tested for chlamydia and gonorrhea, beginning early in pregnancy

Any person who engages in unsafe sex or shares needles or syringes for intravenous drug use should get tested for HIV every year.

Gay and bisexual men who are sexually active should be tested once a year for syphilis, chlamydia, and gonorrhea, or more frequently if they have multiple or anonymous partners. More frequent HIV testing may also be recommended for people in this community. Find out about LGBTQ Inclusive Care at Main Line Health.