Can a person with syphilis spread the disease?

A diagnosis of syphilis can feel overwhelming, especially when you start wondering, “Can a person with syphilis spread the disease even if they feel fine?” Understanding when syphilis is contagious, how it spreads, and how treatment works helps you protect both your health and your partners.

This guide walks you through what you need to know in clear, practical language so you can make informed choices and lower the risk of transmission.

How syphilis spreads

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. You get it through direct contact with a syphilis sore or rash during sexual or very close physical contact.

According to the CDC, a person with syphilis can spread the disease through direct contact with a syphilis sore during vaginal, anal, or oral sex, even if there is no penetration or ejaculation (CDC). These sores, called chancres, are often firm, round, and painless and can appear:

In or around the vagina or vulva
On the penis or under the foreskin
Around the anus or rectum
In the mouth or on the lips

Because chancres can be hidden in the mouth, rectum, or under folds of skin, you may not notice them, yet the infection is still contagious. You cannot catch syphilis from toilet seats, bathtubs, clothing, cutlery, door handles, swimming pools, or hot tubs (Mayo Clinic).

When a person with syphilis is most contagious

Syphilis does not stay the same over time. It moves through stages, and the risk that you can spread the disease changes with each stage.

Primary and secondary stages

You are very contagious in the primary and secondary stages.

Primary syphilis: A painless sore (or several sores) appears at the site where the bacteria entered your body. This might be the genitals, anus, rectum, or mouth. These chancres make it easy to infect sexual partners through direct contact (Mayo Clinic).
Secondary syphilis: If untreated, the infection progresses to a widespread rash, sometimes on the palms and soles, along with other symptoms like fever, swollen lymph nodes, or sore throat. You are still highly contagious during this stage, because the rash and other lesions can shed bacteria.

The Cleveland Clinic notes that a person with syphilis is very contagious and can easily spread the infection to sexual partners during the primary and secondary stages when sores, ulcers, or rash are present, typically within the first weeks to months after infection (Cleveland Clinic).

Early latent and late latent stages

After the visible symptoms go away, syphilis moves into the latent stage.

In early latent syphilis (within the first year after infection), you may still be considered potentially infectious, especially if you recently had symptoms of primary or secondary syphilis or a recent positive blood test.
In late latent syphilis (infection for more than one year, or unknown duration), the CDC notes that latent syphilis itself is not sexually transmissible. People with latent syphilis do not spread the infection to sexual partners through sex (CDC).

However, there is an important exception: even in the latent stage, you can still pass syphilis to a fetus during pregnancy, which is called congenital syphilis (Cleveland Clinic).

Can you spread syphilis without symptoms?

Yes. You can have syphilis and spread it even if you do not notice sores or feel sick.

Syphilis sores can be painless and hidden, so you might never see them. A person with syphilis can still transmit the disease even if they have no symptoms or if symptoms such as painless chancres have healed, which is why medical treatment is necessary regardless of how you feel (Medical News Today).

Even after sores or rashes disappear, the infection can still be in your body. The CDC explains that even after syphilis sores heal, a person can still spread the infection unless they receive appropriate treatment (CDC).

If you are sexually active, especially with multiple partners or if you do not always use barrier protection, regular STI testing, including syphilis screening, is one of the best ways to catch an infection early and reduce the chance of passing it on.

How long can a person with syphilis spread the disease?

Without treatment, a person with syphilis may remain contagious for a long time. You can generally spread the disease:

During the primary stage, while chancres are present
During the secondary stage, when rashes or other lesions are present
Possibly during early latent syphilis, especially within the first year of infection

The Cleveland Clinic notes that someone with untreated syphilis remains contagious until they complete antibiotic treatment. Sores may disappear, but the infection can persist and still be transmitted (Cleveland Clinic).

During late latent syphilis of more than one year, sexual transmission is not expected to occur (CDC). However, vertical transmission from a pregnant person to a fetus can still happen without treatment.

Transmission routes beyond sexual contact

Sexual contact is the main way syphilis spreads, but it is not the only route.

Mother-to-baby (congenital syphilis)

Syphilis can be passed from a pregnant person to their baby during pregnancy or childbirth. Congenital syphilis can cause:

Miscarriage or stillbirth
Premature birth
Severe health problems in the newborn
Developmental issues or even death if untreated

Both the CDC and Cleveland Clinic highlight that syphilis can be transmitted from a pregnant person to their fetus and that this can lead to serious health problems or fetal death if the infection is not treated during pregnancy (CDC, Cleveland Clinic, Mayo Clinic).

Close nonsexual contact with sores

Less commonly, syphilis can spread through very close skin to skin contact, for example through kissing or touching an active sore on the lips, mouth, breasts, or genitals. Mayo Clinic notes that this can happen, but only when there is direct contact with an active lesion (Mayo Clinic).

Casual contact like hugging, sharing a bathroom, or using the same dishes does not spread syphilis.

When are you no longer contagious after treatment?

The good news is that syphilis is curable with the right antibiotics. Once you are fully treated and your healthcare provider confirms that the treatment has worked, you will not continue to spread the infection to sexual partners.

However, timing matters.

Medical News Today reports that syphilis remains contagious for at least one week after completing treatment, so you should avoid sex during this time to prevent spreading the infection (Medical News Today).
The CDC recommends follow up blood tests at 6 and 12 months after treatment to confirm the infection has cleared or to detect reinfection (Medical News Today).

Once your doctor confirms that your blood test results are improving as expected and you have completed the recommended period of sexual abstinence after treatment, your risk of passing syphilis to others is extremely low.

It is important to remember that treatment stops the infection and prevents further damage, but it does not reverse complications that may have already occurred in late stage syphilis (Medical News Today).

Can you get or spread syphilis again after treatment?

Yes. Having syphilis once does not give you immunity. You can be cured and then become infected again if you are exposed in the future.

The CDC notes that a person can get syphilis again after treatment if their sexual partners do not receive testing and treatment, since the infection can be passed back and forth (CDC).

If you have been treated for syphilis, your partner or partners from the past 90 days should be notified, tested, and treated if necessary. Doctors advise this to prevent reinfection and further spread (Medical News Today).

Even if you finish your antibiotics and feel fine, you still need follow up testing and open conversations with partners to avoid getting syphilis again.

How to reduce the risk of spreading syphilis

If you have syphilis, or you are worried you might, there are concrete steps you can take right now to protect yourself and others.

Get tested and treated promptly

If you notice a painless sore in the genital, anal, or mouth area, or if you have a new unexplained rash, especially after unprotected sex, ask for an STI panel that includes syphilis. The earlier you are treated, the easier it is to cure the infection and prevent complications and transmission.

Follow your provider’s instructions exactly for:

Antibiotic type and dosage
Number of injections or pills
Follow up blood tests and visits

Pause sexual activity during the contagious period

While you are being treated and for at least one week after completing treatment, avoid vaginal, anal, and oral sex to lower the chance of infecting someone else (Medical News Today).

After that, ask your doctor when it is safe for you to resume sexual activity based on your specific situation and test results.

Use barrier protection consistently

Condoms and dental dams lower, but do not completely remove, the risk of syphilis transmission. Syphilis spreads through contact with sores or rashes, which may be on skin that a condom does not cover. Using barriers every time you have sex still significantly reduces overall STI risk.

Inform and support your partners

Telling a partner about syphilis is not easy, but it is essential. Sharing this information gives them the chance to get tested and treated, and it reduces the chance that you will be reinfected later.

You can:

Share what your doctor told you about the stage of your infection
Offer to go to a clinic together
Emphasize that syphilis is common, treatable, and nothing to be ashamed of

If you prefer, some clinics and public health departments can help notify partners anonymously.

If you are pregnant or planning pregnancy

If you are pregnant or thinking about becoming pregnant, syphilis testing is critical. Syphilis during pregnancy can be passed to a baby and lead to severe outcomes, including fetal death, if not treated (Cleveland Clinic, Mayo Clinic).

Ask your provider for:

Syphilis screening early in pregnancy
Repeat testing later in pregnancy if you are at higher risk
Immediate treatment if you test positive, to protect both you and the baby

What to remember about spreading syphilis

Here are the core points to keep in mind if you are wondering, “Can a person with syphilis spread the disease?”:

Yes, a person with syphilis can spread the infection, especially in the primary and secondary stages when sores and rashes are present.
You can still be contagious even if you do not see symptoms or if sores have healed, until you are properly treated.
Latent syphilis of more than one year is not sexually infectious, but it can still be passed from a pregnant person to a fetus.
Treatment with the right antibiotics cures syphilis and stops you from spreading it, but you should avoid sex for at least a week after finishing treatment and follow up with blood tests.
You can get syphilis again after treatment if you are exposed to an untreated partner.

If you suspect you might have syphilis, or you know a partner has been diagnosed, the best next step is to schedule an STI test as soon as you can. Getting answers quickly lets you treat the infection early, protect your partners, and move forward with more confidence in your sexual health.