STIs: Is infection possible without sexual intercourse?

Sexually transmitted infections (STIs) are often associated only with sexual intercourse (vaginal, anal, oral). However, transmission is also possible without sexual contact. For example, herpes can be spread through direct skin-to-skin contact, even without penetration. This blog explores the transmission routes of common STIs and offers valuable tips for effective protection.

Table of Contents

• Can you get STIs without having sex?
• Overview: What are sexually transmitted infections?
  • Chlamydia and Gonorrhea
  • Syphilis
  • Herpes
  • Human Immunodeficiency Virus (HIV)
  • Trichomoniasis
  • Human Papillomavirus (HPV)
• 4 tips for effective STI protection
• Summary

Can you get STIs without having sex?

Yes, sexually transmitted infections (STIs) can be contracted without having vaginal, anal, or oral sex. Many pathogens can be transmitted through close skin contact or via infected bodily fluids such as saliva or blood. Below is a closer look at the most common STIs and their typical transmission routes to provide a comprehensive understanding of infection risks.

Overview: What are sexually transmitted infections?

A sexually transmitted infection (STI) refers to the presence of pathogens such as bacteria, viruses, and parasites in the body that are mainly transmitted through sexual contact. The most common STIs and their respective pathogens include:

Source: WHO, 2024

For more comprehensive information on STIs, visit our blog category “Sexually Transmitted Diseases.”

Chlamydia and Gonorrhea

Chlamydia and gonorrhea infect the mucous membranes of the genitals, urethra, throat, eyes, and rectum. The primary transmission route is unprotected vaginal, anal, or oral sex. However, non-sexual transmission is also possible:

• Contaminated hands: Touching infected body fluids, followed by contact with the eyes or genitals.
• Birth transmission: Infected mothers can pass the bacteria to their newborn during childbirth.
• Contaminated sex toys: Sharing sex toys that haven’t been properly cleaned.
• Direct genital contact: Transmission is possible even without penetration, orgasm, or ejaculation.

These infections are not spread through kissing or everyday contact such as hugging, handshakes, or sharing toilets, pools, dishes, or towels (Cleveland Clinic, 2023; NHS, 2024).

Syphilis

Syphilis is transmitted not only through vaginal, oral, or anal sex but also through direct contact with syphilitic skin or mucous membrane lesions. This contact may occur during sex, but transmission is also possible through contact with infectious sores on the genitals, anus, rectum, lips, or mouth. Pregnant individuals with syphilis can transmit the infection to their unborn child via the placenta (congenital syphilis), which can result in miscarriage, stillbirth, or serious complications such as developmental issues, organ damage, or neurological problems in the newborn.

Syphilis is not spread through everyday contact like hugging, handshakes, or sharing toilets, pools, dishes, bedding, or clothing. Kissing typically poses no risk unless active sores are present in the mouth area (Cleveland Clinic, 2022).

Herpes

Herpes is caused by the herpes simplex virus (HSV), where HSV-1 usually causes oral herpes (cold sores) and HSV-2 causes genital herpes. However, both types can affect the mouth and genital areas. Transmission occurs mainly through direct skin or mucous membrane contact. Genital herpes can also be contracted even if the infected person has no visible blisters or is unaware of the infection. Aside from sexual contact, transmission can occur through:

• Kissing: Direct contact with herpes sores, particularly with oral herpes.
• Saliva contact (in oral herpes): For example, drinking from the same glass during an outbreak.
• Contaminated hands: Touching herpes blisters and then touching mucous membranes (e.g., eyes, mouth, or genitals).
• Direct skin contact: In the case of genital herpes, such as during intimate contact without penetration.
• During childbirth: Transmission from an infected mother to the newborn.

Herpes is not transmitted via toilet seats, bedding, swimming pools, or contact with cutlery, soap, or towels (WHO, 2024).

Human Immunodeficiency Virus (HIV)

HIV is mainly transmitted through unprotected vaginal, anal, or oral sex when infected body fluids such as blood, semen, or vaginal secretions enter the bloodstream via mucous membranes or small wounds. Anal sex poses particularly high risk due to the vulnerability of the anal mucosa. HIV can also be transmitted through:

• Sharing needles or syringes: Especially among people who inject drugs.
• Breast milk: From an infected mother to her baby during breastfeeding.
• During childbirth: Through contact with blood and body fluids.
• Open wounds or injuries: Contact between infected blood and open wounds on both individuals.

Due to modern screening and hygiene practices, risks from blood transfusions and medical procedures are now rare but may still exist in areas with insufficient healthcare standards. HIV is not spread through everyday interactions such as shaking hands, hugging, kissing, sneezing, or coughing. The virus is only viable for a very short time outside the human body, so there is no risk of transmission via shared toilets, utensils, towels, bedding, or swimming pools (WHO, 2024).

Trichomoniasis

Trichomoniasis is caused by the parasite Trichomonas vaginalis and is almost exclusively transmitted through unprotected vaginal sex. Additional transmission routes include:

• Contaminated sex toys: Transmission can occur if shared without proper cleaning or protection.
• Moist objects (rare): Infection through shared towels or washcloths that came into contact with infected secretions. This is possible because the parasite can survive briefly in a moist environment outside the body.
• Mother-to-child transmission: In extremely rare cases during childbirth.

The infection is not spread through everyday contact (Mayo Clinic, 2022).

Human Papillomavirus (HPV)

HPV is primarily transmitted through close skin contact during vaginal, anal (even without penetration), or oral sex. The virus can enter the body through any mucous membrane, including the mouth, lips, anus, or genital area. Non-sexual transmission is very rare, for example from mother to child during pregnancy or birth. There is no transmission through everyday contact such as handshakes, toilets, or swimming pools (CDC, 2024).

4 Tips for Effective STI Protection

• Barrier protection: Condoms and dental dams offer protection from direct contact with mucous membranes and infected bodily fluids, reducing the risk of STI transmission during vaginal, anal, and oral sex.
• Regular STI testing: Especially important for individuals with multiple partners or new relationships, since many STIs are asymptomatic and can be unknowingly passed on.
• Open communication: Honest conversations with partners about STI status, test results, and protective measures build trust and help prevent misunderstandings.
• Vaccinations: Vaccines against HPV and hepatitis B can significantly reduce the risk of infection.

Source: WHO, 2024

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Summary

Sexually transmitted infections (STIs) can be spread not only through sexual intercourse but also through direct skin contact or the exchange of bodily fluids such as saliva or blood. Many pathogens, such as herpes, HIV, or syphilis, can be transmitted without penetration via skin-to-skin contact or infected wounds. To protect yourself, it is essential to use condoms, get tested regularly, and communicate openly with your partner. Everyday interactions like hugging or kissing without visible sores usually carry no risk.