STIs vs. STDs: Understanding the Differences

In a topical glossary created by public health experts, infections are defined as "the entrance and development of an infectious agent in a human or animal body, whether or not it develops into an infectious disease" [2].

STIs can be caused by bacteria or by parasites and are often curable with treatment. Here are some of the most common bacterial and parasitic STIs.

Bacterial Vaginosis (BV)

BV can also occur without sexual transmission and falls under the category of vaginitis. Symptoms can be similar to yeast infections (yeast infections can be sexually transmitted). BV is treated with antibiotics prescribed by a healthcare provider.

Chlamydia

Chlamydia is caused by a bacterium called Chlamydia trachomatis and is most common in vulva owners between the ages of 19 and 25. Chlamydia is treated with antibiotics prescribed by a healthcare provider and should be treated promptly to prevent the development of Pelvic Inflammatory Disease (PID).

Learn more about chlamydia and how to get tested with the Chlamydia & Gonorrhea Test.

Gonorrhea

Gonorrhea is caused by a bacterium called Neisseria gonorrhoeae and should be treated as soon as possible to prevent further infection and damage to reproductive organs. Gonorrhea is treated with antibiotics prescribed by a healthcare provider.

Learn more about gonorrhea and how to get tested with the Chlamydia & Gonorrhea Test.

Syphilis

Syphilis is caused by Treponema pallidum, and tests can detect past or active syphilis infections. In 2020, the CDC was notified of nearly 134,000 new cases of syphilis. Syphilis is treated with antibiotics prescribed by a healthcare provider.

Learn more about syphilis and how to get tested with the Syphilis Test.

Trichomoniasis

Trichomoniasis is a parasitic infection caused by the parasite Trichomonas vaginalis. When untreated, vulva owners can be infected for weeks or even years, whereas penis owners' infections typically last less than two weeks. Trichomoniasis is treated with antibiotics prescribed by a healthcare provider.

Learn more about the Trichomoniasis Test.

Pubic lice

This infection is parasitic and usually referred to as "crabs." Treatment is similar to what you would do if you got head lice—medicated creams are commonly used, and removing hair in affected areas may also help.

Pelvic inflammatory disease (PID)

While PID is curable, if untreated it can cause permanent damage to reproductive organs, which can impact fertility. PID is treated with antibiotics prescribed by a healthcare provider.

STDs are caused by viruses that, once they enter the body, remain there—because they persist (active or dormant), they are considered ongoing diseases rather than temporary infections.

Dr. Milton Taylor, a microbiologist, defines viruses as packages of genetic information that enter other cells, take over, and then either kill the host cell and/or continue to replicate themselves [3]. Viruses use the cells in your body to recreate themselves [3]. Here are some of the most common viral STDs.

Hepatitis

Hepatitis C (HCV) requires treatment since it can trigger a variety of symptoms and, if left untreated, may result in liver disease, liver failure, or liver cancer.

Learn more about hepatitis C and how to get tested with the Hepatitis C Test.

Herpes

Herpes is a result of the herpes simplex virus (HSV) and can be commonly found on the genitals and in the mouth. The CDC estimated that "572,000 new genital herpes infections in the United States among people aged 14 to 49" occurred in 2018 [4].

HIV

Human immunodeficiency virus (HIV) is chronic and is something that you will manage for the rest of your life. Luckily, HIV medicine can decrease the amount of the virus in your body, and you can live a long life (and also have a robust sex life).

Learn more about HIV and how to get tested with the HIV Test.

HPV

Human papillomavirus (HPV) is the most common STD in the United States [5]. In most cases—9 out of 10—HPV goes away on its own within two years without causing health problems. But when HPV does not go away, it can cause health problems like genital warts and cancer [5].

STDs and STIs are primarily spread through sexual contact, including vaginal, anal, and oral sex. Some STDs and STIs can also be transmitted through skin-to-skin contact with infected areas, such as kissing or sharing sex toys. Some infections—like HIV—can also be transmitted through sharing needles or other injection equipment.

The first thing STIs and STDs have in common is that they are both sexually transmitted, meaning they are passed from one person to another via sexual contact. Second, both require STI or STD testing for diagnosis (with few exceptions).

Luckily, Everlywell has your back and wants to ensure that you get the testing you need. Browse our options for discreet, at-home sexual health testing kits, which include options such as the HCV Test and Syphilis Test. If your lab results are abnormal, Everlywell will also connect you with its national independent physician network for consultation and appropriate treatment.

While no single prevention method eliminates all risk, several strategies can significantly reduce the likelihood of contracting or transmitting an STI or STD.

• Use barrier methods. Condoms are effective at reducing transmission of STIs spread through genital fluids, including gonorrhea, chlamydia, HIV, and trichomoniasis. Because condoms may not cover all infected skin, they may be less effective against STIs transmitted through skin-to-skin contact, such as syphilis, herpes, and HPV.
• Get vaccinated. Vaccines are available for hepatitis A, hepatitis B, and HPV. Talk to your healthcare provider about which vaccines are right for you.
• Get tested regularly. Many STIs produce no symptoms, so regular testing is the most reliable way to know your status and protect partners.
• Talk openly with partners. Discussing STI testing history with a partner before sexual activity helps both people make informed decisions about their sexual health.