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Syphilis: Who gets and causes

Who gets syphilis?

Anyone can get syphilis. This disease spreads mainly through sexual contact, so you have a greater risk of getting syphilis if you are sexually active and:

  • Have unprotected sex with multiple sex partners

  • Are HIV-positive

  • Are a man who has sex with other men

  • Have sexual partners who test positive for syphilis

If you take antiretroviral treatment (ART) for HIV, you still have a higher risk of developing syphilis if you are sexually active. ART helps to slow down HIV. ART cannot reduce your risk of developing other sexually transmitted diseases, such as syphilis.

You can reduce your risk of developing an STD by either: 1) not having sex at all, or 2) using condoms (or dental dams) if you do have sex.

What causes syphilis?

This disease is caused by bacteria. To survive, these bacteria need to live on or inside the human body. They cannot survive on a toilet seat, towel, or bedding.

Syphilis spreads through intimate contact

You cannot get syphilis from a toilet seat, towel, or bedding.

Hotel maid holding clean towels

How do you get syphilis?

Syphilis is a contagious disease. Most people catch it during sex.

When your sex partner has syphilis, the bacteria that cause the disease create open sores. These sores may appear on the genitals, where you might see them. The sores can also develop inside the mouth, anus, or vagina. These sores tend to be painless, so many people don’t know they have syphilis sores.

When you touch these sores during sex, the bacteria spread from your partner to you. Once the bacteria attach to your body, they start multiplying. This can happen quickly, within hours.

Syphilis can spread from one person to another through:

  • Oral, anal, or vaginal sex

  • Genital-to-genital contact

  • An open wound in your skin

  • Kissing (if syphilis has caused mouth sores)

A woman who is pregnant can give syphilis to her unborn baby: Syphilis can spread from mother to baby before (or during) birth. The medical term for this type of syphilis is “congenital syphilis.”

Testing can tell whether a woman who is pregnant has syphilis. If a pregnant woman is not tested, she may be unaware that she has syphilis and pass the disease to her unborn child. Babies who are infected in the womb might die before they are born. Some might be born with serious birth defects.

Most pregnant women in the United States get tested for syphilis during a prenatal checkup. When the disease is caught early, syphilis can be treated before it affects the baby.

To find out how doctors find, treat, and cure syphilis, go to:

Syphilis: Diagnosis and treatment

Getty Images

Forrestel AK, Kovarik CL, et al. “Sexually acquired syphilis Historical aspects, microbiology, epidemiology, and clinical manifestations.” J Am Acad Dermatol 2020;82:1-14.

Stary G, Stary A. “Sexually transmitted infections.” In: Bolognia JL, et al. Dermatology. (fourth edition). Mosby Elsevier, China, 2018: 1447-59.