The Most Common STIs in the U.S. and How to Protect Yourself

Sexually transmitted infections are far more common than most people realize. Millions of new cases occur in the United States every year, and many of them go undiagnosed because symptoms are mild or never appear at all. Knowing which STIs are most widespread, and how to lower your risk, is an important step in taking control of your sexual health.

The Most Common STIs

Chlamydia is the single most reported bacterial STI in the country. It often has no symptoms but, if untreated, can lead to complications like infertility. Gonorrhea is also very common and is becoming more difficult to treat as antibiotic resistance increases. Trichomoniasis, caused by a parasite, affects millions of people annually and can cause irritation or discharge, though many never notice symptoms.

Viral infections are also widespread. Human papillomavirus (HPV) is the most common STI overall, with most sexually active people exposed at some point in their lives. Some strains clear naturally, while others can lead to genital warts or certain cancers. Herpes simplex virus (HSV-1 and HSV-2) causes oral or genital outbreaks that come and go throughout life. HIV remains a serious infection, but early detection and treatment mean people can live long, healthy lives. Syphilis, while less common than chlamydia or gonorrhea, has been rising steadily in recent years and can cause severe complications if untreated.

Why These Infections Spread Easily

One of the biggest challenges is that many STIs are silent. You or your partner may feel healthy and still carry an infection. Because of this, relying on symptoms is not enough. Routine screening is the only reliable way to know your status.

How to Protect Yourself

Protecting yourself does not mean avoiding sex; it means making smart choices. Using condoms or dental dams lowers the risk of transmission. Regular testing keeps you informed about your status and allows for early treatment if needed. Vaccines, such as those for HPV and hepatitis B, provide powerful protection and are worth discussing with your healthcare provider. Open conversations with partners about testing and protection also reduce uncertainty and stigma.

The Bottom Line

STIs are common, but they are also manageable with awareness, prevention, and treatment. Understanding which infections are most prevalent and taking steps to protect yourself creates peace of mind and supports healthier relationships. Testing, protection, and open communication are the cornerstones of keeping yourself and your partners safe.

Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. If you have questions about your health, symptoms, or risk factors, you should consult with a licensed healthcare provider.