Can you get reinfected with the same STI?

Many people assume they are permanently protected after successfully treating a sexually transmitted infection (STI). Unfortunately, this is a misconception: Some STIs can recur—even after a complete recovery. In this article, you’ll learn whether and why reinfection is possible, which pathogens are particularly involved, and how you can effectively protect yourself.

Table of contents

• Can you get the same STI again?
• Which STIs can occur more than once?
• Why are you not immune after an STI?
• How can you recognize a reinfection?
• What can you do to avoid getting infected again?
• When should you get an STI test?

Can you get the same STI again?

Yes—this is often possible. Even if an STI has been successfully treated, that does not automatically mean your body is permanently protected. Especially with bacterial infections like chlamydia or gonorrhoea, reinfection can occur—even with the same pathogen. Viral STIs like herpes or HPV can also recur (Cleveland Clinic, 2023).

Which STIs can occur more than once?

Sexually transmitted infections (STIs) can happen more than once. Depending on the pathogen, either reinfection or reactivation is possible:

• Reinfection means you get infected again—through repeated contact with the pathogen.

• Reactivation means the pathogen was already in your body, retreated (e.g., into nerve cells), and becomes active again later—often triggered by stress or a weakened immune system.

STIs with a risk of reinfection:

• Chlamydia

• Gonorrhoea

• Syphilis

• HIV

• Trichomoniasis

• Hepatitis B (if no immunity is present)

STIs with a risk of reactivation or reinfection:

• Genital herpes (HSV)

• Human papillomavirus (HPV)

• Hepatitis B (in chronic infection)

Source: WHO, 2025; Mayo Clinic, 2024

Why are you not immune after an STI?

STIs usually do not result in long-term immunity. This means that even if you have been infected before, you are not automatically protected from getting it again.

Bacterial pathogens like chlamydia, gonorrhoea, or syphilis generally do not trigger a lasting immune response. The immune system “forgets” the pathogen, which is why reinfection is always possible—especially if your partner is not treated at the same time.

Viral pathogens such as herpes simplex virus (HSV) or certain HPV types remain permanently in the body. After the initial infection, they retreat into certain cells—such as nerve cells or tissues—and can later reactivate. Such reactivation can be triggered by stress, other infections, or hormonal changes—even without renewed contact with the virus.

HIV is not a reactivatable infection in the classic sense. Instead, in the absence of protection—such as condoms or the use of PrEP (pre-exposure prophylaxis)—there is a consistently high risk of reinfection through unprotected sex or blood contact.

Source: WHO, 2019; CDC, 2021

That’s why regular STI testing is essential—even after a previously treated infection. This way, you can reliably protect yourself and others.

How can you recognize a reinfection?

A reinfection often presents similar symptoms to the initial one. These may include:

• Burning or pain during urination

• Unusual discharge from the vagina or penis

• Itching, blisters, or skin changes in the genital area

• General discomfort or fever

Note: Many STIs show no noticeable symptoms—both during the initial and subsequent infections. That’s why regular testing is especially important to detect infections early and prevent unintentional transmission (Mayo Clinic, 2024).

What can you do to avoid getting infected again?

Here are a few steps to reliably protect yourself:
✔ Use condoms or dental dams, especially with new or changing sexual partners.
✔ Talk openly with your partner about past test results or current symptoms.
✔ Get tested regularly, particularly after changing partners.
✔ Make sure both you and your partner get treated at the same time if an STI is diagnosed.
✔ Refrain from sexual activity until treatment is complete.

Source: CDC, 2024

When should you get an STI test?

There are specific situations where testing is particularly recommended:

• After unprotected sex

• When you have new or multiple sexual partners

• If you notice symptoms like discharge, burning, or skin changes

• If your partner is diagnosed with an STI

• After treatment of a previous STI, to rule out reinfection

• Routinely—every 6 to 12 months—for general health monitoring

Source: NHS, 2024

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