Sexually Transmitted Infections (STIs)

Reviewed by: HU Medical Review Board | Last reviewed: September 2019 | Last updated: February 2023

Sexually transmitted infections (STIs, also sometimes referred as sexually transmitted diseases, STDs) are infections that are transmitted from person to person during sexual activity. HIV is an example of an STI. STIs can be caused by viruses, bacteria, or parasites. Activities that carry the highest risk of transmitting a sexually transmitted infection include anal, vaginal, and oral sex. Other common sexually transmitted infections besides HIV include, but are not limited to:1

  • Herpes (herpes simplex virus or HSV), especially genital herpes
  • Gonorrhea
  • Human papillomavirus (HPV)
  • Chlamydia
  • Syphilis

How are STIs related to HIV?

Individuals with STIs including genital herpes, syphilis, chlamydia, and gonorrhea, among others, are three times more likely to get or transmit HIV. Essentially, the previous risk of any specific sexual behavior increases if there is another STI present during the act.2-4 This increase in risk can happen for a variety of reasons. Some STIs, like herpes, lead to open sores on or around the genitals that can serve as areas for transmission. Even STIs that don’t commonly produce sores, like chlamydia, can still lead to an increased amount of inflammation and inflammatory cells in the body that can be infected by HIV.

Additionally, when some STIs that co-occur with HIV are left untreated, like herpes, the affected individual may become even more infectious, or have a higher viral load, than another HIV-positive individual who does not have a co-occurring herpes infection. The more infectious a person is, the greater the likelihood that the virus will be transmitted.2,4 Further, HIV and other STIs share common risk factors, such as having multiple partners or unprotected sex.1 This could also be a reason why coinfections may be present.

Signs of an STI

The signs and symptoms of an STI can vary based on where the exact infection is, what caused the infection, and the gender of the individual with the STI (some STIs affect different individuals in different ways). Common STI symptoms include, but are not limited to:

  • Frequent urination
  • Painful urination
  • Blisters or sores, especially around the genital region or anus
  • Fever
  • Unusual discharge from the penis or vagina

Additionally, some STIs may not have any obvious symptoms. If you are concerned you may have an STI, or are experiencing potentially STI-related symptoms, contact a healthcare provider about STI testing. Free, confidential testing sites can also be found by visiting the HIV Testing Site Locator.

Treatment of STIs

The treatment of an STI depends on what is causing the infection. For example, STIs caused by bacteria, such as chlamydia, syphilis, or gonorrhea are treated with antibiotics. STIs caused by parasites can also be treated with medications. There are currently no curative medicines for STIs caused by viruses. However, individuals with a virally-caused STI can take medicines to alleviate symptoms or keep the infection under control.1

Part of the treatment and management of STIs involves testing others who may be at risk and treating them too. This may include current and former sexual partners if you have a confirmed STI. In some situations, you may also need to be retested after treatment to ensure that the treatment was successful.

Prevention of STIs

Prevention of STIs involves practicing safe sex behaviors. If an individual is sexually active, it is important to use barrier protection, such as condoms (specifically condoms made out of latex or polyurethane), especially when having sex with multiple or unknown partners. Limiting the number of sexual partners an individual has is also a method of reducing the risk of STIs.1

Unlike other STIs, recent research has suggested that those with HIV who take antiretroviral medications (ART) and achieve, and maintain, an undetectable viral load have virtually no risk of transmitting the virus to an HIV-negative partner. This idea has been referred to as “undetectable = untransmittable” or “U=U”. Therefore, the risk of HIV transmission to an HIV-negative partner can be greatly reduced when an HIV-positive partner is on ART and taking their medications as prescribed. The risk of getting HIV can also be significantly reduced with the use of PrEP (pre-exposure prophylaxis). PrEP is a medication taken every day by individuals at risk of getting HIV (such as those with an HIV-positive partner), but who do not currently have the virus.1,5-7

Talking about STIs

Identifying, treating, and preventing STIs all start with having open conversations with your healthcare provider about your risk and any potentially STI-related symptoms. In some cases, your healthcare provider may initiate these conversations. However, other times, they may not bring up STIs or ask about STI-related concerns. Although it may be scary or feel overwhelming, you may need to start the conversation around these issues yourself if they are concerning for you. STIs are common and talking about them is the best way to get a correct diagnosis and on the road to treatment.

If you feel uncomfortable talking to your healthcare provider about your sexual health but feel as though you should be tested for an STI, you can find a testing location that provides free and confidential testing near you here.

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