STI stands for sexually transmitted infections. These are infections that are mainly (but not exclusively) spread through sexual contact. Examples include chlamydia, gonorrhea, syphilis, or HIV. Many STIs initially cause no symptoms but, if left untreated, can lead to serious health issues.

STD stands for sexually transmitted diseases. The term is often used interchangeably with STI but refers more specifically to the illness that may develop as a result of an infection. While an infection can exist without causing any complaints, it is considered a “disease” once symptoms appear.

Today, the term STI is increasingly used because it is more precise: not every infection automatically leads to a disease. In German, the word Geschlechtskrankheit (venereal disease) is still common, but it is inaccurate and can be stigmatizing. By using STI, we emphasize the medically correct and more neutral expression.

Chlamydia are bacteria (Chlamydia trachomatis) and are among the most common sexually transmitted infections. They often cause no symptoms but, if left untreated, can lead to serious complications such as infertility.

• Young people between 15 and 25 years old
• Gay and bisexual men of all ages
• The specific form LGV (lymphogranuloma venereum) occurs in Germany almost exclusively among men who have sex with men

• Vaginal, anal, or oral contact with mucous membranes
• Transmission through direct contact (smear infections) during sex is also possible

• Condoms significantly reduce the risk
• Early detection: In Germany, statutory health insurance covers one free chlamydia test per year for women up to the age of 25. Ask your health insurance provider if you are eligible.

Often none which is why many infections go unnoticed. If symptoms do appear, they may include:

• Women: Discharge (watery or purulent), itching, burning when urinating
• Men: Clear discharge from the urethra, burning when urinating
• Rectal infection: Discharge, itching, sometimes pain
• Throat infection: Usually no symptoms
• LGV: Severe pain, swollen lymph nodes in the groin, bleeding, problems with bowel moveme

• Urine sample
• Swabs from the urethra, cervix, rectum, or throat
• For LGV: specific testing to distinguish it from other chlamydia infections

• Usually antibiotics for at least one week (for LGV, three weeks)
• Sexual partners from the past few weeks are typically treated as well, even without a separate test, to avoid “ping-pong infections”

• Chlamydia are easily treatable
• Early detection helps prevent long-term complications
• Regular testing is especially important if you have changing sexual partners

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. If left untreated, it can affect various organs and lead to serious long-term complications but it can be effectively cured with antibiotics.

• Around 7,000–8,000 new cases per year in Germany
• Most affected: men who have sex with men (MSM)
• More common in large cities
• Reporting requirement: cases are anonymously reported to the local health authority

• Mainly through close mucous membrane contact during vaginal, anal, or oral sex
• Infection occurs via small wounds or direct contact with ulcers or moist warts (condylomata lata)
• Less common: transmission from mother to child during pregnancy, through blood, or via needle-stick injuries

• Condoms significantly reduce the risk (by about 95%) but do not offer complete protection, as sores may occur outside the condom-covered area
• Regular testing if you have risk contacts especially recommended for MSM with changing partners (every 3–6 months)
• Pregnant persons in Germany are routinely tested

Syphilis progresses in several stages:

• Early stage (around 3 weeks after infection): Painless ulcer at the site of entry (genitals, anus, mouth) + swollen lymph nodes
• Secondary stage: Skin rash (often on palms and soles), flu-like symptoms, moist warts in skin folds, hair loss
• Latent stage: Often years without symptoms, but still detectable
• Late stage (rare): Severe damage to the brain, heart, nerves, and other organs

• Blood test (antibody detection)
• In early stages, direct detection of the pathogen from the ulcer
• If there is suspicion of nervous system involvement: analysis of cerebrospinal fluid

• Standard treatment: Penicillin injection (once or over several weeks, depending on the stage)
• Alternative for penicillin allergy: other antibiotics (e.g. doxycycline)
• Important: Sexual partners from the past weeks or months should also be treated to avoid reinfection

• Syphilis does not leave immunity reinfection is always possible
• Early detection protects against severe long-term complications
• Testing is especially important with new or changing partners

Gonorrhea, commonly known as “the clap”, is a sexually transmitted infection caused by bacteria (Neisseria gonorrhoeae). It can affect the genitals, rectum, and throat, often without noticeable symptoms.

• An estimated 25,000–30,000 new cases per year in Germany
• The second most common bacterial STI after chlamydia
• Particularly affected: men who have sex with men (MSM) and young adults with changing partners

• Vaginal, anal, and oral sex
• Transmission is also possible via fingers or sex toys if no condoms or dental dams are used
• Mother-to-child transmission can occur during childbirth
• No transmission through toilets, towels, or swimming pools

• Condoms and dental dams significantly reduce the risk
• Regular testing if you have frequently changing partners; for MSM, testing every 3–6 months is recommended
• Tests can check for both chlamydia and gonorrhea at the same time

Often none, especially in the throat or rectum. If symptoms do appear, they may include:

• Women: Increased discharge, spotting, lower abdominal pain
• Men: Yellow-purulent discharge from the urethra, burning when urinating
• Rectal infection: Itching, discharge, sometimes bleeding
• Throat infection: Usually symptomless, sometimes sore throat
• If left untreated, gonorrhea can lead to inflammation, infertility, and chronic pain.

• Urine sample
• Swabs from the urethra, cervix, throat, or rectum
• Modern PCR tests are highly reliable and also detect asymptomatic infections

• Standard: single antibiotic injection (ceftriaxone)
• If resistance is suspected: targeted antibiotic treatment after testing
• Important: Sexual partners from the past 60 days should also be treated, even without their own test, to prevent reinfection

• No lasting immunity, reinfection is always possible
• Resistant strains (“super gonorrhea”) are increasing worldwide; timely and correct treatment is crucial
• Follow-up testing is recommended, especially for throat infections or during pregnancy

HIV (human immunodeficiency virus) attacks the immune system. If left untreated, it can lead to AIDS. Thanks to modern medication, people with HIV today can live almost as long as those without HIV if treatment begins early.

• Worldwide, around 40.8 million people live with HIV
• In Germany, around 96,700 people live with HIV, about 8% of whom are unaware of their infection
• The number of new infections in Germany has remained stable for years

• Sexual transmission: Mainly through unprotected anal or vaginal sex (highest risk with receptive anal sex)
• Blood contact: Sharing needles or syringes, blood transfusions (extremely rare in Germany due to strict screening)
• Mother-to-child transmission: During pregnancy, childbirth, or breastfeeding (in Germany, now almost completely preventable thanks to treatment)
• Not transmitted by: Shaking hands, hugging, kissing, sharing dishes

• Condoms: Significantly reduce the risk
• PrEP (pre-exposure prophylaxis): Preventive medication, up to nearly 100% effective when taken correctly
• PEP (post-exposure prophylaxis): Emergency medication that must be started within 72 hours after possible exposure
• Regular testing: Early diagnosis makes HIV very well treatable

• Often no noticeable symptoms at first
• In the first weeks after infection: flu-like symptoms such as fever, night sweats, sore throat, and body aches
• Skin rash, swollen lymph nodes, fatigue
• Nausea, diarrhea, or weight loss
• Later stages (without treatment): increasing immune deficiency, frequent infections, opportunistic diseases

• Blood sample (venous blood)
• Finger-prick blood (capillary blood)
• Oral swab / saliva sample
• Plasma / serum for highly sensitive laboratory tests

• Antiretroviral therapy (ART): Daily tablets or long-acting injections keep the viral load so low that HIV becomes undetectable
• “U = U”: Undetectable = Untransmittable when HIV remains below detection level, it cannot be passed on during sex
• Treatment should start as soon as possible after diagnosis

• With proper treatment, people living with HIV can lead almost normal lives today
• Modern therapies are very well tolerated and often available as a single tablet
• The earlier the diagnosis, the better the prognosis

Hepatitis C is a viral infection that primarily affects the liver. If untreated, it can cause hepatitis, liver cirrhosis, and liver cancer but with modern medications, it is now curable in almost all cases.

• Worldwide: around 50 million people
• Germany: an estimated 189,000 chronic infections
• Many affected people are unaware of their infection, as it often causes no symptoms

• Primarily through blood-to-blood contact, e.g. sharing needles or equipment when using drugs, unsterile tattoos or piercings, or needle-stick injuries in medical settings
• Sexual transmission is rare but the risk increases if other STIs are present
• Mother-to-child transmission during childbirth is possible
• Not transmitted by: Shaking hands, kissing, or sharing dishes

• Do not share needles, syringes, or related equipment
• Ensure sterile conditions for piercings and tattoos
• Use condoms in risk situations
• Practice good hygiene in medical and private settings (e.g. personal razors, toothbrushes)

Often none, or only vague complaints such as fatigue, muscle pain, or concentration problems. Possible signs of an acute infection include:

• Yellowing of the skin or eyes (jaundice)
• Dark urine, light-colored stool
• Pain in the upper right abdomen

If left untreated, hepatitis C can lead to cirrhosis or liver cancer over many years.

• Blood test for hepatitis C antibodies
• If positive: confirmation by virus detection in the blood (HCV-RNA test)
• Liver examinations to assess damage (e.g. ultrasound, elastography)

• Modern tablet therapies (DAAs) for 8 to 12 weeks
• Cure rates above 95%
• Treatment is covered by health insurance in Germany
• No vaccine available
• Reinfection is possible after successful treatment

• Early diagnosis prevents severe late complications
• Regular testing is important if you are at risk
• Treatment today is short, well tolerated, and highly effective

HPV are very common viruses that can affect the skin and mucous membranes. There are over 200 types: some cause harmless warts, others can lead to cancer.

• More than 80% of all sexually active people will get an HPV infection at some point
• In most cases, the infection clears on its own within 1–2 years
• Anyone can be affected

• Mainly through sexual contact (vaginal, anal, oral) even without penetration
• Less commonly, from mother to child during childbirth
• Condoms lower the risk but do not provide full protection

• Vaccination: Provides very reliable protection against the most dangerous HPV types. Recommended for all children and adolescents between 9 and 14 years (catch-up vaccination until age 17)
• Cost coverage: Many health insurance providers cover the HPV vaccine up to a certain age. Be sure to check with your insurance about their coverage limits
• Condoms: Reduce the risk and also protect against other STIs
• Early detection: Regular check-ups, such as Pap smears at the gynecologist

• Low-risk types: Genital warts (unpleasant, but not dangerous)
• High-risk types: Cell changes that can develop into cancer, e.g. cervical, anal, or throat cancer

• Cervical swab (Pap test) to detect early cell changes
• HPV DNA test for direct detection of the virus, often combined with a Pap test
• Visible warts in the genital or anal area can be clinically diagnosed
• For men, there are no routine screenings; testing is usually symptom-based

• In many cases, an HPV infection clears on its own without treatment
• Visible changes such as genital warts can be removed with creams, freezing, laser therapy, or surgery
• Cell changes on the cervix are monitored and removed depending on the findings
• There is currently no treatment that eliminates the virus itself

• Most HPV infections resolve on their own
• Only a small percentage become chronic and may cause cancer which is why regular check-ups are important
• HPV can affect anyone, regardless of gender

Herpes is an infection caused by herpes simplex viruses (HSV), typically presenting with painful blisters on the lips, genitals, or other body areas. The virus remains permanently in the body and can reappear during times of weakened immunity or stress. There are two main types: HSV-1 and HSV-2.

• HSV-1: Almost everyone is infected; it usually appears as cold sores on the lips but can also spread to the genitals or anus of a partner
• HSV-2: Around 20% of the population is infected; it typically affects the genitals and is painful there. Heterosexual individuals are affected more often. Once infected, outbreaks can occur at any time, though frequency varies greatly from person to person

• Genital, rectal, oral: Mucous membrane-to-mucous membrane contact
• Smear infection: Contact with infectious fluid from blisters

• Condoms reduce transmission risk only slightly. HSV can also be transmitted “around the condom” through kissing, oral sex, or touch (e.g. via fingers)
• Avoid direct contact with blisters or sores
• If blisters are present on the genitals or lips, avoid kissing and oral/sexual contact until they heal (about 1–2 weeks)

• Genital, rectal, oral: Burning, painful, itchy blisters
• The lesions (blisters) always heal again, with or without treatment but herpes viruses remain “hidden” in the nerves and can reappear in the same spot, especially during stress, intense sun exposure (on the lips), or other simultaneous infections
• In cases of weakened immunity, severe courses with organ involvement or brain infection are possible

• Medical examination based on typical blisters and symptoms
• Swab of blister fluid for direct virus detection in the laboratory
• Blood test for antibodies if the infection is unclear or occurs without visible symptoms

• Mild cases: Local treatment with ointments
• Severe cases: Antiviral medication (drugs that inhibit viral replication) as tablets or intravenously

• Herpes viruses remain in the body for life once infected
• Herpes is not curable, but outbreaks can be treated and well controlled
• Stress, sun, or a weakened immune system can trigger a recurrence
• Blisters are contagious, especially through direct skin or mucous membrane contact