Syphilis and People with HIV

HIV and Syphilis: What’s the Connection?

Syphilis is a sexually transmitted infection* (STI) caused by a type of bacteria. Cases of syphilis have been increasing in the U.S. In fact, a CDC report showed that syphilis cases increased 80 percent from 2018-2022.

Gay, bisexual, and other men who have sex with men (MSM) are disproportionately impacted by syphilis. In 2022, MSM accounted for almost half (45%) of all male cases of primary and secondary (P&S) syphilis—the most infectious stages of the disease. 

Co-infection with HIV is common. According to CDC, in 2022, approximately 36% of MSM with P&S syphilis also had HIV. And MSM who are HIV-negative and diagnosed with P&S syphilis are more likely to get HIV in the future.

Having a syphilis sore may make it easier for HIV to enter your body. And having HIV and another STI may also increase the risk of HIV transmission.

Syphilis is treatable and curable. However, having HIV can make syphilis harder to treat, especially if you have advanced or untreated HIV. If you have both HIV and syphilis, it’s important to take your HIV medicine as directed and take a full cycle of medication to cure the syphilis.

How Is Syphilis Spread?

Syphilis can be transmitted during anal, vaginal, and oral sex without a condom with a partner who has syphilis. Any sexually active person can get it.

Syphilis is passed from person to person through direct contact with a syphilis sore. Because syphilis sores can be painless and hidden in the vagina, anus, under the foreskin of the penis, or in the mouth, it is possible to have syphilis sores and not know it.

If you are pregnant and have untreated syphilis, it can be passed to the baby during pregnancy or birth. This is called congenital syphilis, and it can lead to poor birth outcomes, including birth defects and infant death.

You can NOT get syphilis through casual contact with objects such as toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing, or eating utensils.

How Can You Know If You Have Syphilis?

Syphilis infection develops in stages (primary, secondary, latent, and tertiary). Each stage has different signs and symptoms. Read this information from CDC about signs and symptoms during each of the stages.

However, many people with syphilis do not have symptoms or do not notice them. The only way to know is to get tested.

Getting Tested for Syphilis

If you are sexually active, talk openly with a health care provider about your sexual history and ask whether you should be tested for syphilis or other STIs. If you don’t have a provider, use the HIV.gov Locator to find an STI testing and treatment site near you.

According to CDC, you should get tested regularly for syphilis if you are sexually active and

• are a gay or bisexual man;
• have HIV;
• are taking pre-exposure prophylaxis (PrEP) for HIV prevention;
• have partner(s) who have tested positive for syphilis; or
• Have certain risk factors for syphilis, like living in a community with high rates of syphilis

In addition, all pregnant people should receive syphilis testing at their first prenatal visit. Some pregnant people need to receive syphilis testing again during the third trimester at 28 weeks and at delivery.

The testing process: Most of the time, health care providers will use a blood test to test for syphilis. If you have open sores, a provider may swab the area to take a sample of fluid and test it. As required by the Affordable Care Act, most health plans must cover syphilis testing at no cost to you. 

Telling your partner(s): If you have syphilis, it is important to tell your sexual partner(s), if it is safe to do so, for their own health and to prevent you from getting syphilis again. Your local health department may offer partner services—a free service to help locate and inform your partner(s) of their potential exposure and provide them with testing, counseling, and linkage to care. Ask your testing site about partner services or call your health department.

Questions for your health care provider: Consider taking this list of questions when you go to get tested.

How Can You Prevent Syphilis?

The only 100% effective way to avoid getting syphilis and other STIs is to not have vaginal, anal, or oral sex. If you are sexually active, you can do the following things to lower your chances of getting other STIs:

Use condoms the right way every time you have sex. Condoms protect against syphilis by preventing contact with a sore. However, there may be sores outside the area covered by a condom. Contact with these sores can still transmit syphilis.

Talk to your health care provider about doxy PEP: medicine to prevent STIs.

• Doxy PEP is a way to prevent getting an STI. It involves taking a dose of the antibiotic doxycycline ideally within 24 hours but no later than 72 hours after condomless oral, anal, or vaginal sex. The drug can help prevent the STI from spreading to your system. The sooner you can take it after sexual contact, the better!
• Doxy PEP has been proven to reduce your chances of getting a bacterial STI (syphilis, chlamydia, and gonorrhea) by about two-thirds. But it is not for everyone. Doxy PEP has been proven effective in gay, bisexual, and other men who have sex with men (MSM) and transgender women. Studies of doxy PEP effectiveness among cisgender women are ongoing.
• Doxy PEP requires a prescription, so you’ll need to see a health care provider to get it. Talk to your provider and tell them you’re interested in taking doxycycline as PEP for STIs. You can also contact a local STI clinic and see if they are offering it. Find a clinic near you. They will write a prescription so that you have doxy PEP on hand when you may need it.

If you are sexually active, you can also avoid syphilis by being in a long-term mutually monogamous relationship with a partner who has been tested and does not have syphilis.

Can Syphilis Be Cured?

Yes. When diagnosed early, syphilis can be cured with appropriate antibiotics prescribed by a health care provider. However, treatment might not undo any damage the infection has already done. Also, due to increased demand, the U.S. is currently experiencing a shortage of the type of penicillin used to treat syphilis.

Having syphilis once does not protect you from getting it again. Even after successful treatment, you can get syphilis again.

If left untreated, syphilis can lead to very serious health problems, such as tumors; blindness; paralysis; and damage to the nervous system, brain, and other organs.

STI National Strategic Plan

The U.S. Department of Health and Human Services (HHS) released the first-ever STI National Strategic Plan (STI Plan) in December 2020, providing a road map for the prevention, diagnosis, care, and treatment of STIs, including syphilis.

In June 2023, HHS released the STI Federal Implementation Plan, a companion document outlining federal actions to reduce the burden of STIs in the United States through 2025.

Learn More

Learn more by visiting CDC’s About Syphilis, About Congenital Syphilis, and About STIs and Gay Men fact sheets.

* The terms STI and STD: The term sexually transmitted infection (STI) refers to a virus, bacteria, fungus, or parasite that is passed from person to person through sexual contact. A sexually transmitted disease (STD) is a disease that develops from an STI. Some people use both terms. Many health organizations – including HIV.gov – are using the term STI more often, except when referring to data or information from sources that use STD.