Risky sexual activities for the transmission of sexually transmitted infections

Sex is a normal and often enjoyable part of all our lives, but practising it is associated with certain risks. Different sexual activities carry different levels of risk of acquiring various sexually transmitted infections (STIs). The level of transmission risk for individual STIs depends on how the infection is transmitted. In this article, we take a closer look at which risky activities are associated with the transmission of HCV, HIV, and syphilis, and how to reduce the risk of transmission in individual sexual activities.

Hepatitis C

To understand which sexual practices are risky for the transmission of the HCV virus, we need to realize that HCV is transmitted exclusively through blood—meaning there must be blood-to-blood contact. Therefore, risky are all activities where blood may be present, including due to unintended injuries (such as tears and other small wounds) during sex. Another important fact is that HCV can survive outside the human body, which means that surfaces and objects (e.g., sex toys, condoms, etc.) that came into contact with infectious blood can remain infectious for up to 90 days. Risky sexual activities for HCV transmission are therefore considered to be:

• anal sex without a condom,
• group sex without a condom during penetration (vaginal and anal), or not using a new condom when changing partners,
• fisting without gloves or not using new gloves when changing partners,
• sharing a container of lubricant during group fisting,
• sharing penetrative sex toys (vaginal and anal) without a condom or not using a new condom when changing partners,
• sharing tools for anal douching or enemas,
• sex during menstruation,
• chemsex can also be risky due to lowered inhibitions, caution, and vigilance.

The risk of HCV transmission can be reduced by using condoms, lubricant gel, and latex gloves. If sex lasts longer, it is recommended to change the condom every half hour. When changing partners during sex, it is necessary to use a new condom and gloves each time.

The only way to find out whether you have become infected is to get tested. Recommendations for regular testing for certain reference groups are as follows:

Human immunodeficiency virus

HIV is transmitted through blood and bodily fluids that contain T-lymphocytes from an infected person (i.e., semen, pre-ejaculate, rectal secretions, vaginal secretions, or breast milk). Specifically, this infected blood or bodily fluids must come into contact with the blood of an uninfected person, for example through small cracks and other injuries on the mucosa. Transmission is also possible through intact mucosa or inflammatory ulcers, but not through unbroken skin. The probability of transmission depends on several factors, such as the ability of the mucosa to absorb fluids, what type of fluid it is, etc.

So, if we were to rank forms of sex by their risk of HIV transmission, it would be as follows:

There is no possibility of HIV transmission through contact with the saliva of an HIV-positive person, including kissing, biting, or spitting. There is no possibility of HIV transmission through saliva containing a small amount of blood.

You can reduce the risk of HIV transmission by proper condom use and by using lubricant gel. There are also other factors that influence the risk of HIV transmission:

• A low or “undetectable” viral load significantly reduces or eliminates the possibility of HIV transmission.
• Pre-exposure prophylaxis (PrEP) significantly reduces the possibility of acquiring HIV.
• Post-exposure prophylaxis (PEP) significantly reduces the possibility of acquiring HIV.
• Male circumcision reduces the possibility of HIV transmission from woman to man.
• Risk-reducing practices, such as withdrawal (when ejaculation does not occur into the body of the HIV-negative partner) or strategic positioning (i.e., when the HIV-positive partner is in the receptive, not the insertive position), reduce the possibility of HIV transmission.
• Sexually transmitted infections (STIs) can, under certain circumstances, increase the possibility of HIV transmission.
• Chemsex can also be risky due to lowered inhibitions, caution, and vigilance.

The risk of HIV transmission can be reduced by using condoms, lubricant gel, and latex gloves. If sex lasts longer, it is recommended to change the condom every half hour. When changing partners during sex, it is necessary to use a new condom and gloves each time.

The only way to find out whether you have become infected is to get tested. Recommendations for regular testing for certain reference groups are as follows:

Syphilis

Syphilis is transmitted through blood and through direct contact with an infectious sore caused by syphilis—specifically through sexual contact, but also through contact with another part of the body (e.g., a hand) if there is an open cut on it. A sore caused by syphilis can be external or internal. It can be located, for example, in the mouth, on the penis, in the vagina, and/or in the rectum. Syphilis as such can be transmitted even without obvious symptoms. A person with untreated syphilis is most infectious in the primary and secondary stages.

Due to syphilis’ low resistance to external environmental influences, you cannot contract syphilis through casual contact with objects such as toilet seats, pools, hot tubs, bathtubs, sharing clothing, door handles, or sharing a lubricant container.

Risky sexual activities for syphilis transmission are all those in which a person is exposed to contact with an infectious sore—i.e., all forms of unprotected sex (vaginal, anal, oral). By protection we mean methods that create a “barrier”: a penis condom, an internal (vaginal) condom, and a dental dam/oral dam (for oral sex—both vaginal and anal), or for practices such as fisting, the use of latex gloves and similar. It is important to realize that sores can also occur in areas not covered by a condom. Contact with these sores can still transmit syphilis.

Chemsex can also be risky due to lowered inhibitions, caution, and vigilance. If sex lasts longer, it is recommended to change the condom every half hour. When changing partners during sex, it is necessary to use a new condom and gloves each time.

The only way to find out whether you have become infected is to get tested. Recommendations for regular testing for certain reference groups are as follows:

Especially risky sexual practices for the transmission of infections

Fisting (vaginal and anal) – painful irritation of the rectum and vagina or injuries such as small bleeding cuts, abrasions, or tearing of the rectal or vaginal wall can occur. This increases the risk of infection transmission.

Some BDSM practices (knife play, needle play, impact play) – since all infections are transmitted through blood, the presence of blood during these practices increases the risk of infection transmission.

Sex during menstruation – the presence of blood increases the risk of infection transmission.

Gagging, deep throating, swallowing – unintended injury from biting or vomiting can occur. This increases the risk of infection transmission.

Pissing, scat – the risk of infection transmission is mainly present if urine contains blood or bacteria, which may not be visible to the naked eye. With feces, there is transmission of pathogenic intestinal bacteria and protozoa (e.g., salmonellosis), and there is also a high risk of hepatitis A transmission.

Double penetration – painful irritation of the rectum and vagina can occur, increasing the risk of infection transmission.

Chemsex – due to lowered inhibitions, caution, vigilance, and longer endurance during sex, the risk of infection transmission increases.

In all cases, it is necessary to keep in mind safer sex principles—proper use of a penis condom, internal (vaginal) condom, dental dam/oral dam, latex gloves; it is also recommended to have trimmed nails, not to swallow a partner’s fluids, and to change the condom after every half hour of use. When changing partners, put on a new condom and gloves.

Sources:

Expert statement on scientific knowledge about HIV in the context of criminal law. Barré-Sinoussi F. et al. Journal of the International AIDS Society 2018, 21:e25161,
https://doi.org/10.1002/jia2.25161

CORE WP5 | Integrated Rapid Testing Training. 2023. Miguel Oliveira, Lisbon.

How to practice safer sex: sexual practices. Rozkoš bez rizika.