In recent years, there has been an increase in sexually transmitted infections (STIs).

As for Sitges, the report from the Center for Epidemiological Studies on HIV and Other Sexually Transmitted Infections of Catalonia (CEEISCAT), published in 2021, indicates that the vast majority of STIs have increased in recent years.

In the last year, the first major disease in Sitges has been chlamydia, the second gonorrhea, the third syphilis. In Sitges we have an incidence of these diseases that exceeds the average for Catalonia, the incidence of syphilis, for example, triples the average for Catalonia and that of HIV still doubles it.

At Colors Sitges Link we have been working for years on health promotion and prevention programs. This guide wants to be a first approximation to Sexually Transmitted Infections, so that you have basic, clear and concise information about the most common STIs.

Prevention begins with your knowledge. We hope that the guide will be useful to you.


STIs are infections caused by bacteria, viruses, fungi, and parasites, usually transmitted during sexual relations, mainly through vaginal and anal penetration and oral sex (mouth-to-penis, mouth-to-vagina or mouth-to-anus contact). 

Some STIs are visible, causing symptoms such as ulcers or sores (open wounds), secretions or pus, warts or condylomas; while others may not show symptomatology during long periods of time or go unnoticed, which is the case with HIV, wart-less human papillomavirus (HPV), or hepatitis A, B and/or C. 

In many cases an STI may not cause symptoms, particularly when the infection takes place in less visible organs, such as the inside of the vagina, anus, or throat. Only four STIs are transmitted strictly through sexual relations: gonorrhea, chlamydia, syphilis and trichomoniasis. All other STIs can also be transmitted non-sexually.  Lesbians, gays, bisexuals and trans people (LGBT) may often encounter added difficulties when discussing our sex lives with others who, through their remarks, make it clear they are uninformed about our everyday lives. 

If this happens to you, go to our entity or to the CAP, there you will be able to find information about the socio-sanitary resources that exist in your area, since not presenting symptoms, even if they disappear, after having had them, does not mean that the infection is cured.

In company of a trusted health care professional, you can assess if any regular check-ups may be needed.



If you have been diagnosed with an STI or think you might have one, you can seek out information about how to carry on with your sex life in the best conditions. 

Learning what to specifically do and how to reduce risks depending on the type of STI you might have will be important for your health. 

It is also key that you keep in mind that open sores on your genitals or internally can facilitate the acquisition of other infections like HIV, since wounds concentrate greater amounts of white blood cells, which are particularly sensitive to the virus.



This virus is transmitted through specific fluids: blood, semen, vaginal fluid, and breast milk. In order for transmission to take place, the virus must reach the bloodstream through absorbent mucus, such as that of the anus or the vagina, or through open wounds or lesions caused by other STIs. There are three modes of transmission: sexually, through the blood, or mother-to-child.

This virus is transmitted through unprotected anal, vaginal, and oral sex. Therefore, oral sex, in absence of other STIs and open wounds, is considered a low-risk practice. If you already have an STI, the risk of HIV infection is greater. For instance, an STI can cause an ulcer or a wound on the skin, which helps the virus enter the organism. 

For oral sex, latex barriers or dental dam can be used; for a number of other sexual practices, gloves and lubricant can help protect and reduce risks. 

Condom use during sex prevents the transmission of HIV and other STIs, regardless of whether your viral load in undetectable. 

If you are diagnosed with HIV and you are under treatment with an undetectable viral load (less than 50-20 copies/mL), you will not transmit the virus to your sexual partners, even during unprotected sex. However, you will not be protected from other STIs, which may put your health at risk.



HPV is the most common type of sexually transmitted infection. There are many types of HPVs. Some are harmless, while others may cause condylomas or even cancer. 

HPV is easily transmitted through skin-to-skin contact, when your vulva, vagina, cervix, penis or anus come into contact with the genitals or mouth and throat of another person, usually during sex. 

Health care professionals can use various techniques to remove/cauterize condylomas. High-risk cases can easily be treated, preventing it from turning into cancer. This is why HPV testing and regular Pap smears are the best ways of reaching diagnosis. Even though condoms, dental dam and other barriers do not provide complete protection, they can help decrease the chances of HPV transmission.



Syphilis is an STI caused by a bacteria that can affect the vagina, the anus, the penis, the scrotum and, in some cases, the lips and the mouth. 

You can prevent it by using condoms or dental dam. 

The infection takes place when the vulva, the vagina, the penis, the anus or the mouth come into contact with the lesions (syphilitic chancres and/or “copper penny” spots) of a person with syphilis, usually during sex. Syphilis can be transmitted or acquired regardless of ejaculation. 

Syphilis is easily cured with antibiotics, though it can cause permanent damage if left untreated, since the disease has various phases. 

Having had syphilis in the past does not protect you from reinfection. 


Gonorrhea is an STI caused by a bacteria that is transmitted through unprotected anal, vaginal and oral sex. 

Many people do not show symptoms. Those who do show symptoms might experience a burning sensation when urinating, testicular pain, penile secretion, a change in color of vaginal fluids, vaginal bleeding between periods or discomfort in the lower abdomen. 

To reduce risks, you can use a male or female condom. 

A sample taken from the genital, pharyngeal or anal areas 

-depending on your sexual practices- is necessary for diagnosis. Gonorrhea is treated with antibiotics. 

Having had gonorrhea in the past does not protect you from reinfection. 


Chlamydia is an STI caused by a bacteria that is transmitted by having unprotected anal, vaginal or oral sex. 

Many people do not show symptoms. Those who do show symptoms may experience a burning sensation when urinating, testicular pain, penile secretion, a change in the color, quantity and smell of vaginal fluid, bleeding between periods, discomfort in the lower abdomen and even, in women, bleeding after sex. 

When symptoms appear in the rectum, they may include pain, secretion, and rectal bleeding. 

For diagnosis, a sample take from the genital area is needed. In other cases, a urine sample is required. If you have had oral or anal sex, pharyngeal or anal samples may also be necessary. 

Having had a previous infection does not protect you from reinfection.



Hepatitis is an inflammatory disease in the liver that can harm its functions and is sometimes caused by viruses that result in different types of hepatitis. 

Hepatitis A is transmitted through poor hand hygiene or through contaminated food or water. It can be transmitted through certain sexual practices that involve coming into contact with an infected person’s feces, such as anilingus (rimming).  

To protect yourself, you can wash your hands with soap and water after using the toilet and before handling food. During sex you can also use latex barriers such as condoms, dental dam and latex or vinyl gloves. 

If you have had hepatitis A in the past, you will be immune to it the rest of your life.  

The hepatitis B virus is primarily found in the blood, but can also be found in other bodily fluids such as semen or vaginal secretions.

As with hepatitis A, hepatitis B may subside within a few weeks without treatment, though it can become chronic.  

To protect yourself during sex, you can use condoms and dental dam.

As for hepatitis C, it is located primarily in the blood. Special care should be taken when carrying out sexual practices that involve coming into contact with the blood of a person with hepatitis C. In order to avoid infection, it is important to use a condom during anal and vaginal sex. You should also avoid sharing pointed objects, needles, syringes or other equipment used for injection and snorting. Lubricant and latex gloves can also help reduce risks.



Vaccines will also help you reduce risks, though they only exist for certain STIs.  

There are vaccines for Hepatitis A and B that are available to the entire population.  

There are also vaccines for certain types of HPV. They are administered in specific cases, so we recommend you check first with a trusted health care professional.



If you have any questions you can contact: 

We would like to thank the FELGTBI+ Health Programme for the documentation and information in this guide.