Syphilis may still be contagious for a short time after treatment. People can take precautions to help avoid transmission before and after treatment. This can include avoiding sex for at least 1 week.

Syphilis is a sexually transmitted infection (STI). A person with syphilis may have symptoms that come and go and can take time to develop. People can also have no symptoms despite still having the condition.

Syphilis is generally curable. However, the infection can still spread from one person to another for some time after treatment.

This article discusses how long syphilis remains contagious after treatment, including when a person can have sex again. It also discusses how long treatments last, preventing syphilis, and more.

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Syphilis can be contagious for a short time after treatment. A person may need to wait for at least 1 week after they finish treatment before having sex, as it may still be possible for the infection to spread during this time.

A person may need syphilis testing around 6 to 12 weeks after treatment. This is to help ensure that the treatment has been effective.

The Centers for Disease Control and Prevention (CDC) recommends people undergo syphilis testing at least 6 and 12 months after treatment, or more often if necessary, to help detect reinfection.

Doctors will typically recommend that a person does not have sex until at least 1 week after they finish treatment for syphilis. They also need to wait until their symptoms resolve.

The CDC recommends people with syphilis notify their sexual partners. Medical professionals also recommend contacting any sexual partners a person has had in the last 90 days. This is so they can also seek testing and treatment if necessary.

The incubation period of syphilis is around 10 to 90 days. It can take 21 days or longer for a person to experience symptoms.

Initial symptoms of syphilis usually include one or more open sores called chancres. They tend to develop in the genital area or inside the mouth.

As chancres feel painless and firm, people may not notice them. They usually heal within 3 to 6 weeks without treatment. However, people may still then be able to pass syphilis on to others. Their syphilis can also develop further, leading to serious complications.

Even if a person’s chancres have gone away, they still need to seek professional medical treatment.

Medical professionals usually recommend the antibiotic medication penicillin to treat syphilis. How long a person’s treatment lasts depends on the stage of their syphilis.

  • Early stages: A person usually requires a single dose of penicillin.
  • Late stages: Medical professionals usually recommend three shots of penicillin, administering one shot per week for 3 weeks.
  • Syphilis that affects their nervous system: If syphilis affects the nervous system, a person may require penicillin through an intravenous infusion into the veins. They will usually receive this daily for 10 to 14 days.

If penicillin is unsuitable, a doctor may recommend oral doxycycline or ceftriaxone injection. A person’s doctor can provide them with more information about what treatment they recommend.

Learn more about the stages of syphilis.

Treatment may completely cure syphilis. However, this treatment will not cure any damage or complications that syphilis may cause if it progresses to later stages.

People with hearing loss due to syphilis will still have hearing loss after syphilis treatment. If the condition has damaged a person’s heart, they may still need heart surgery to repair it.

A person’s doctor can advise on any additional treatments they may require for complications of syphilis.

The best way to prevent STIs, including syphilis, is by not having oral, anal, or vaginal sex.

There are steps a person can take to reduce the likelihood of syphilis. These include:

  • using a condom when they have vaginal or anal sex
  • covering the penis with a condom or the vagina with a latex or plastic square during oral sex
  • not sharing sex toys, and washing and covering them with a new condom before use
  • not sharing needles if injecting drugs

Condoms can help prevent contact with sores. However, chancres may occur in areas that condoms do not cover. If a person has contact with these sores, they can still get syphilis.

The CDC also recommends regular testing if a person is sexually active and:

  • is a gay or bisexual male
  • has HIV
  • is taking preexposure prophylaxis (PrEP), a medication for HIV prevention
  • has a partner who has tested positive for syphilis

A pregnant person with syphilis can also pass it on to their unborn child. Medical professionals should test all pregnant people for syphilis during their first prenatal visit and sometimes at later stages.

Syphilis may be contagious for at least 1 week after completing treatment. This means that, during this time, it is best for a person to avoid having sex.

A person may need follow-up tests to determine if the treatment has been successful. Their doctor can advise on when they may require the tests.

Although it may not be possible to completely prevent syphilis, a person can take steps to reduce the likelihood of reinfection. These include the use of condoms, not sharing sex toys, and not sharing needles.