Sexually transmitted infections (STIs), formerly called sexually transmitted diseases (STDs), are diseases that primarily spread through sexual contact. STIs can be bacterial, such as chlamydia, gonorrhea, and syphilis, or viral, including herpes, HIV, and HPV. Transmission may involve body fluids (blood, saliva, semen, vaginal secretions) or direct skin-to-skin contact. While abstinence is the only way to prevent STIs altogether, knowing the risk factors for transmission can help you protect yourself if you are sexually active.
Most sexually transmitted infections (STIs) do not go away on their own without treatment. Bacterial STIs, such as syphilis, chlamydia, and gonorrhea, require treatment with antibiotics to clear. Viral STIs, such as herpes and HIV, are treated with antiviral medications to address symptoms, prevent recurrent outbreaks, and halt disease progression.
STIs are infections that are spread through intimate contact including vaginal, oral, or anal sex and foreplay. Some STIs are spread through body fluids including blood, saliva, semen, and vaginal secretions, while others are spread through skin-to-skin contact. STIs can produce obvious symptoms such as genital itching, discharge, or sores, however, people can have an STI with no symptoms.
All sexually active men and women should be tested for STIs from time to time, but how often depends on your lifestyle. People who have multiple sex partners, sexually active gay and bisexual men, and women under 25 should be tested annually. STI testing is recommended for all pregnant women. In addition, all sexually active people from ages 13 to 64 should be tested for HIV at least once.
The only sure way to avoid getting an STI is to abstain from all intimate contact. For most people, that isn’t practical, but fortunately, STIs are largely preventable. Consistent and correct use of condoms helps, but they are not equally effective for all infections. Understanding how STIs are spread and taking appropriate precautions reduces the risk of STI transmission.
The cost of testing for STIs depends on a few factors. Under the Affordable Care Act, some STI tests fall under preventive care and must be covered by insurance free of charge under certain circumstances. For example, sexually active women under 25 get free preventive screenings for chlamydia and gonorrhea each year, and HIV and syphilis screenings are free for all men and women.
Some sexually transmitted diseases (STIs) are easily treatable, while others are not. Bacterial STIs can be cleared with antibacterial treatment, but viral STIs are more difficult to treat. Currently, hepatitis B, herpes simplex virus (HSV), human immunodeficiency virus (HIV), and human papillomavirus (HPV) are incurable. Antiviral medications are used to treat the symptoms or halt the progression of these diseases, but there is no cure.
A bacterial infection is an infection caused by bacteria. Bacteria are single-celled organisms that have many different purposes. Infectious bacteria reproduce quickly in your body making you ill. They are treated with antibiotics. Bacterial STIs include chlamydia, gonorrhea, and syphilis.
Discharge from the vagina or the penis can be a symptom of a sexually transmitted disease or other infection. Vaginal discharge is most often a normal occurrence, but penile discharge is not. Abnormal vaginal discharge can indicate infection and may be foul smelling, thick or chunky, and white, yellow, or green. If you have abnormal vaginal or penile discharge, see your doctor.
An ectopic pregnancy is a nonviable pregnancy in which the fertilized egg has implanted outside the uterus. Sometimes called a tubal pregnancy, it commonly occurs in the fallopian tubes, but the egg may also implant on the cervix or elsewhere in the abdomen. Ectopic pregnancies can't reach viable status and may be life-threatening if left untreated.
Pelvic inflammatory disease (PID) is an infection of the reproductive organs. Commonly caused by an untreated sexually transmitted disease, such as chlamydia or gonorrhea, PID occurs when bacteria travels through the cervix to the uterus and fallopian tubes. PID can lead to complications if left untreated.
A viral infection is an infection caused by a virus. Viruses are microscopic organisms that are transmitted from person to person. Some viruses, like the common cold, influenza, and COVID-19, can cause upper respiratory infection, while enteroviruses commonly cause vomiting and diarrhea. Viral sexually transmitted infections include HIV, herpes, HPV, and hepatitis B.
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Centers for Disease Control and Prevent. Diseases & related conditions: What are STDs? Updated November 4, 2016.
Centers for Disease Control and Prevention. Sexually transmitted disease preventive services coverage. Updated August 18, 2020.
Centers for Disease Control and Prevention. Which STD tests should I get? Updated June 30, 2014.
U.S. National Library of Medicine. Bacterial infections. Updated October 1, 2020.
U.S. National Library of Medicine. Viral infections. MedlinePlus. Updated October 19, 2020.
World Health Organization. Sexually transmitted infections. Updated June 14, 2019.