Many of us will at some point in our lives experience the sinking feeling that accompanies the news that we have contracted a sexually transmitted infection (STI), also known as STDs. According to Planned Parenthood, half of Americans will get an STI at some point. For the majority of people, it will be curable with short-term treatment, but for some, an STI will be life changing and devastating.

Sexually transmitted infections (STIs) are infections that pass from one person to another during sexual contact. STI is a broad term used to categorize many diseases and infections that are all transmitted in a similar manner but are tested, prevented and treated in different ways.

Aren’t they called STDs?

Infections are only called diseases when they cause symptoms, and many STIs do not have symptoms. Nonetheless, people commonly use the term sexually transmitted diseases or STD, even when there are no signs of disease. The technical term for all of the infections and disease we will cover in this blog is STI.

How common are STIs?

So you’re having sex or thinking about having sex, and you’d like to know how to protect yourself against pregnancy and sexually transmitted infections? We applaud your efforts to educate yourself and protect your health.

We’ve compiled the latest information on STI prevalence in the United States to help you be aware of the seriousness of STIs and to help you understand your chances of getting an STI.

Perhaps you’ve already contracted an STI? As you will see from the statistics below, you are not alone. Chances are you will receive a simple treatment for it. If it is a more serious STI, there are support groups where you can speak to people in a similar situation.

In 2010, the Centers for Disease Control and Prevention (CDC) compiled the most recent STI information for three of the most common STIs and compiled it in a 184- page packet available here. For an overview of that packet, other statistics from the CDC, and information from additional sources*, read on:

STI Statistics

Human Papilloma Virus (HPV)

6.2 million new cases each year

The statistic above is from the American Social Health Association. The CDC estimates that at least 50% of sexually active people will have genital HPV at some time in their lives. According to the CDC, 10 percent of people with HPV infections will develop persistent dysplasia or cervical cancer (women only).

Genital Herpes

Approximately one million new cases per year

Genital herpes has long been the most prevalent viral sexually transmitted infection. Every 30 seconds, another person gets genital herpes. Genital herpes affect nearly 20% of the United States population. Genital herpes can be treated, but it cannot be cured.

Chlamydia

1,244,180 cases in 2009

This is the largest number of cases reported to the CDC for any sexually transmitted condition. This may be due, in part, to better reporting agencies and practices. Regardless, in an age where birth control is readily available to Americans, to have the highest reportage of an STI is unfortunate news.

Pelvic Inflammatory Disease (PID)

One million women per year

PID is a serious infection that harms women’s reproductive organs and is primarily caused by untreated chlamydia or gonorrhea. It is usually, but not always, the result of sexually transmitted infections.

Gonorrhea

301,174 cases in 2009

Gonorrhea saw a dramatic 74% decline from 1975-96, followed by a ten-year plateau. In the last three years, instances of this infection have begun decreasing again. Bravo!

Syphilis

13,997 cases in 2009

2009 saw the highest incidence of syphilis since 1995. This is a 5% increase from 2008, making it unlikely that economic hardships played a primary role in the  increase.

Hepatitis B

Approximate total of 4,500 cases in 2009

This is the lowest rate ever recorded for hepatitis B, according to HIVandHepatitis.com.

HIV & AIDS

70,000 cases in North America in 2009

Statistics were published by Joint United Nations Programme on HIV/AIDS (UNAIDS). One in five people with HIV are thought to be unaware of having the condition.

Trichomoniasis (Trich)

7.4 million new cases per year in the U.S.

Trichomoniasis is often called “trich” and can be treated with a prescription medicine.

Pubic Lice

Estimated three million people treated each year

Pubic lice are also known as “crabs.” The statistics on cases of pubic lice are not very dependable, as not everyone is treated by a doctor, and there is no required reporting of pubic lice. Also, it’s possible for the same person to have several infections in one year. Pubic lice are primarily spread through sex play, but can be spread through day-to-day contact as they are capable of living in eyebrows and other non-pubic hair.

Chancroid

28 cases in 2009

According to the CDC, this disease, commonly found in developing countries, has generally declined since 1987.

Genital Warts

Genital warts statistics are difficult to assess. HPV is responsible for genital warts, and the strains of HPV that lead to genital warts are some of the most high-risk. High-risk strains of HPV are more likely to lead to cervical cancer; because of this, genital warts present more of a risk to women than men.

Up next, a guide to STI prevention.

*Statistics are provided by the CDC unless otherwise noted.