Irene Fuertes, dermatologist: "All sexual relations carry a risk of STIs, not just penetration."

When talking about sexually transmitted infections (STIs), the focus is often on vaginal or anal penetration. However, limiting prevention to these practices alone leaves out infections that can occur from the first moments of intimate contact. Caressing, oral sex, or even skin-to-skin contact can be enough to transmit some STIs.

Expanding the concept of safe sex is essential to protecting sexual health. "All sexual intercourse must be considered a risky practice, not just penetration," warns Dr. Irene Fuertes, a dermatologist at Hospital Clínic Barcelona . She clarifies that when she mentions penetration, she doesn't just mean vaginal penetration, but also oral and anal penetration.

Oral sex is often underestimated in terms of its potential for transmission. "It's often thought that there's no risk of transmission, but there is," explains Dr. José Luis Blanco, an internist in the Infectious Diseases Department at Hospital Clínic Barcelona. In fact, HIV can also be transmitted this way, although the risk decreases significantly if the infected person maintains an undetectable viral load.

Some infections are easily transmitted without penetration, such as human papillomavirus (HPV), genital herpes, or syphilis. "They are all very prevalent, occupy many appointments, and do not require penetration to be transmitted," warns Dr. Fuertes. She also emphasizes that they can be transmitted even without ejaculation.

Genital and oral herpes are among the STIs most easily transmitted through direct contact, even without penetration. However, their diagnosis is often complicated, and therefore, their true incidence could be much higher than reported. The most recent data estimate around 46.3 cases per 100,000 inhabitants, although this figure could be just the tip of the iceberg.

HPV is one of the most common STIs worldwide, with approximately 102.3 cases per 100,000 inhabitants. Many of these infections go unnoticed because they resolve spontaneously within a few months. However, HPV is of particular health significance because some types are associated with cancers such as those of the cervix, vulva, vagina, penis, and anus.

Syphilis can also be transmitted, with a prevalence six times higher in men than in women. Most cases are diagnosed in people over 25 years of age, especially in men who have sex with other men. In Spain, in 2019, 5,822 cases were reported, equivalent to 13.29 cases per 100,000 inhabitants. If not detected early, it can become latent and affect nervous or vascular tissue.

How to prevent the transmission of STIs?

In the face of these threats, prevention remains the most effective tool. The consistent and correct use of barrier methods, such as the male condom , remains essential to reduce the risk of infection. If lubricants are used, it is recommended to avoid oil-based lubricants—such as butter, oils, cosmetic creams, or petroleum jelly—as these can weaken the latex and increase the likelihood of condom breakage. The female condom , made of polyurethane or nitrile, is also an effective alternative when used consistently. For oral sex, latex dental dams can be used, which help reduce the risk of infection.

Health professionals also recommend limiting the number of sexual partners and avoiding relationships with strangers or those under the influence of certain drugs that may impair the ability to make safe decisions. It is also essential to avoid sharing sex toys without sterilizing them or covering them with a new condom after each use. Finally, they recommend being careful with sharp or cutting objects—syringes, razor blades, tattoo or piercing instruments—and always discard or sterilize them.

Regular medical checkups, especially for those who engage in high-risk sexual practices, are key to detecting any infections early and receiving appropriate treatment. Furthermore, during these appointments, the appropriateness of vaccination can be assessed, although vaccines are currently available only for certain sexually transmitted infections.

Prevention What vaccines are there?

There are vaccines to prevent three sexually transmitted infections:

• Hepatitis B: It has been part of the official vaccination schedule in Spain since 1993 for adolescents and since 2005 for newborns. Those who have not been vaccinated or who come from other countries without this immunization should consult their doctor to assess their status and get vaccinated if necessary.
• Hepatitis A: Vaccination is recommended for people who engage in risky sexual practices, especially men who have sex with men.
• Human papillomavirus (HPV): Since 2007, the vaccine has been part of the national vaccination schedule for girls between 9 and 14 years of age, with a two-dose schedule. Since 2022, vaccination has been systematically extended to boys and girls to protect the entire population, and is funded for both groups. It is also recommended and funded for women and men under 26 years of age, as well as for people with HIV or at specific risk groups.