Sexually transmitted diseases (STDs), often referred to as sexually transmitted infections, are incredibly common throughout the United States and the rest of the world. In fact, in the U.S. about 1 in 2 sexually active people will contract an STI or STD by the time they turn 25 years old. In the U.S. and elsewhere, many STDs and STIs are on the rise, while recent scientific advancements have helped curb the rates of others.

Young people account for about half of all new cases of sexually transmitted diseases and infections, but only about 12% of people in this age group are tested in any given year, meaning that while millions of people, especially those between 15 and 24, are living with STDs, it’s likely that most of them don’t know it.

Use this page to learn more about the statistics and prevalence of some of the most common STDs in the United States and throughout the world.

All STDs

Across the world every day, more than 1 million sexually transmitted diseases are acquired. Just four conditions, all entirely treatable and curable, account for the vast majority of all STD infections across the world every year:

  • Chlamydia (131 million)
  • Gonorrhea (78 million)
  • Trichomoniasis (143 million)
  • Syphilis (5.6 million)

In addition to new infections, hundreds of millions of people throughout the world are living with a sexually transmitted disease, including human papillomavirus (80 million in the U.S. alone), genital herpes (500 million in the world) or HIV (37 million in the world).

In addition to the sheer human toll of illness from STDs, the U.S. economy loses about $16 billion every year as a direct result of the prevalence of such infections. The truth is that anyone who has sex is at risk of contracting one or more sexually transmitted diseases or infections, and the only way to be sure that you remain healthy and that you don’t spread disease to your sexual partners is to get tested regularly.

Chlamydia

About 3 million Americans are infected with chlamydia every year, but about half of those cases go unreported because the infected individuals’ bodies don’t show any obvious signs of the STD. About two-thirds of new cases of chlamydia occur in people 15-24 years of age, and about 1 in 20 sexually active young women (14-24) have chlamydia, according to CDC estimates.

Highest chlamydia infection rates (cases per 100,000 people)

Alaska 799.8
Louisiana 742.4
Mississippi 707.6
New Mexico 651.6
South Carolina 649.8

Several states have seen large increases in their rates of chlamydia cases over the past few years, with 11 states seeing their rates increase by at least 25%.

Increases in chlamydia infection rates (percentage increase in infections per 100,000 people), 2013-2017

New Hampshire 40%
Connecticut 40%
Maine 32%
Nevada 31%
Utah 28%
California 28%
Oregon 26%
North Carolina 26%
Colorado 26%
Iowa 25%
Virginia 25%

Women are more likely than men to contract chlamydia, though among those over 40, men are more likely to have chlamydia.

Reported chlamydia cases per 100,000 population (15+) by age group and sex

Age group Male Female
15–19 924.5 3,265.70
20–24 1,705.40 3,985.80
25–29 1,091.90 1,725.40
30–34 598.9 725.7
35–39 351.1 361.8
40–44 197.5 170.8
45–54 106.3 63.3
55–64 37.5 17.9
65+ 6.7 2.5

Hepatitis

Hepatitis is most often caused by a virus, and the infection attacks the body’s liver. Most viral hepatitis cases are caused by one of three strains of the virus — A, B or C. All three strains have different typical infection methods, though both hepatitis B and C can be sexually transmitted.

Hep B is more closely associated with sexual transmission than hep C, but it is possible for hep C to be spread sexually. Hep C is particularly concerning for members of the baby boomer generation, who are at an elevated risk of having hep C without even knowing it, possibly because of medical practices that were common during the period of 1945 to 1965 in which it was less common to sterilize needles after every use.

More than 4 million Americans are living with either hep B or hep C, though the exact figure is not known because many more people are infected without knowing it. About 75% of people living with hep C are baby boomers, and an estimated 67% of those who have hep B don’t know it.

Incidents of both hep B and hep C have risen recently, and the opioid crisis is being blamed largely for the rise in hep B, which is spread easily among injection drug users.

Acute hepatitis B infections, 2012-2016

2012 2,895
2013 3,050
2014 2,791
2015 3,370
2016 3,218

Acute hepatitis C infections, 2012-2016

2012 1,778
2013 2,138
2014 2,194
2015 2,436
2016 2,967

 Herpes

Genital herpes is caused by infection of one of two viruses, herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). While either type of the virus can cause sores on either the face or genitals, HSV-1 is more closely associated with facial or oral herpes, while HSV-2 more frequently causes sores in the genital area. While herpes cannot be cured, it’s very common, and about 1 in 6 Americans have genital herpes, while more than half have oral herpes.

Women are more likely than men to have either strain of herpes, but prevalence of both HSV-1 and HSV-2 have fallen over the past couple of decades.

Herpes prevalence by sex and type (% of 14-49 age group infected)

Type Male Female
HSV-1 45.20% 50.90%
HSV-2 8.20% 15.90%

Change in herpes prevalence by type, 2000-2016

Type 2000 2016
HSV-1 59.40% 48.10%
HSV-2 18% 12.10%

HPV

By far the most common sexually transmitted disease is human papillomavirus. In fact, almost all sexually active people will contract the virus at some point in their lives. More than 200 strains of HPV have been identified, but only about 40 of them can infect a person sexually and even fewer strains are responsible for causing cancer.

Men are more likely than women to have either oral or genital HPV.

HPV prevalence by sex

Type Male Female
Oral 11.50% 3.30%
Genital 45.20% 39.90%

While most cases of HPV go unreported, HPV is the leading cause of cervical cancer, which kills more than 4,000 women every year. It’s estimated that HPV is responsible for more than 90% of all cases of cervical cancer and large majorities of cancers of the anus, vagina, vulva and penis.

Highest HPV-associated cancer rates (cases per 100,000 people)

Kentucky 15.67
West Virginia 14.94
Mississippi 14.39
Florida 14.27
Arkansas 14.1

HIV

More than 1 million Americans are estimated to be living with HIV, and HIV infection rates in much of the rest of the world remain quite high, and a total of about 37 million people around the globe are living with the virus that causes AIDS.

HIV diagnosis rates in the U.S. have fallen steadily over the past several years, though some regions in the country are seeing diagnosis rates creep back up.

HIV diagnoses per 100,000 people by year and region

Region 2011 2012 2013 2014 2016 2016
Northeast 13.9 13.5 12.5 12.5 11.6 11.2
Midwest 8 8.1 7.9 7.5 7.7 7.5
South 18.3 17.5 16.9 17 16.9 16.8
West 10.4 10.4 9.8 10.4 10.2 10.2

Gay and bisexual men account for about 66% of all HIV diagnoses and 82% of cases among men. Among racial and ethnic groups, African-American and Hispanics/Latinos are disproportionately affected by HIV.

HIV diagnosis rate by race/ethnicity (cases per 100,000 people)

African-American 43.6
Hispanic/Latino 17
Multiracial 12.9
Native American/Alaska Native 10.2
Native Hawaiian/Pacific Islander 8.5
Asian 5.5
White 5.2

Gonorrhea

Gonorrhea is a common bacterial infection that can be spread during vaginal, oral and anal sex. Commonly referred to as “the clap,” gonorrhea is estimated to cause more than 800,000 new infections in the U.S. every year, though just over half are reported to federal health officials.

Gonorrhea rates are on the rise across the U.S., jumping by 63% nationally between 2013 and 2017. Rates peaked in the mid-1970s but have gone up all but one year since 2009.

Highest gonorrhea infection rates (cases per 100,000 population)

Mississippi 309.8
Alaska 295.1
Louisiana 256.7
South Carolina 254.4
Alabama 245.7

While several southern states have some of the highest infection rates for gonorrhea, the states that have seen their infection rates grow the fastest are all in other regions of the country. More than a dozen states have seen their rates jump by 100% or more.

Increases in gonorrhea infection rates (percentage increase in infections per 100,000 people), 2013-2017

Wyoming 523%
Idaho 347%
New Hampshire 322%
Montana 239%
Colorado 186%
Oregon 179%
Utah 154%
Maine 153%
Iowa 152%
Massachusetts 145%
Rhode Island 138%
New Mexico 134%
Washington 117%
Vermont 110%

Overall, men are more likely to have gonorrhea than women, but some age groups have wide variation between the sexes.

Reported gonorrhea cases per 100,000 population (15+) by age group and sex

Age group Male Female
15–19 323.3 557.4
20–24 705.2 684.8
25–29 645.9 413.7
30–34 431.6 223.3
35–39 291.8 129.3
40–44 181.6 63.8
45–54 112.8 25.7
55–64 46.6 7.2
65+ 8.3 0.8

Syphilis

Among the more common STDs, syphilis is one of the more dangerous. That’s because untreated syphilis can cause permanent blindness, brain damage and even death. In addition to being an easily spread STD, syphilis can be passed from a pregnant woman to an unborn child, and rates of congenital syphilis have been on the rise. Additionally, the rise in IV drug use is considered a major contributor to the increase in syphilis among otherwise relatively low-risk populations.

Overall, rates of primary and secondary syphilis (the non-congenital kinds) have surged by 72% in the U.S. since 2013, jumping 15% between 2016 and 2017 alone.

Highest syphilis infection rates (cases per 100,000 people)

Nevada 20
California 17.1
Louisiana 14.5
Georgia 14.4
Arizona 13.6

In addition to a large national increase, syphilis rates have surged in many parts of the country, with 20 states seeing increases of 100% or more.

Increases in syphilis infection rates (percentage increase in infections per 100,000 people), 2013-2017

Montana 820%
Maine 513%
West Virginia 325%
Idaho 322%
Vermont 320%
Mississippi 300%
Wyoming 250%
North Dakota 241%
Arizona 216%
Oklahoma 206%
Nevada 174%
North Carolina 173%
Kansas 156%
New Mexico 151%
Alabama 129%
Washington 127%
Tennessee 121%
New Jersey 115%
Kentucky 111%
Hawaii 100%

Men are far more likely than women to be diagnosed with syphilis, a distinction that applies in every non-child age group the CDC measures.

Reported syphilis cases per 100,000 population (15+) by age group and sex

Age group Male Female
15–19 10.1 3.2
20–24 41.1 7.8
25–29 51.9 7.1
30–34 39.3 5.1
35–39 30.3 4.1
40–44 20.5 2.8
45–54 17.8 1.5
55–64 7.3 0.5
65+ 1.5 0.1

 Trich

Trichomoniasis, or trich, is a very readily spread parasite that travels in sexual fluids. While most people who get trich aren’t virgins, the infection is so common that even people who’ve never had intercourse can get it. The CDC estimates that more than 3.5 million people have trich.

While trich can infect both men and women, women are much more likely to display symptoms, so they’re more likely to be diagnosed with the STD. About 75% of people with trich never show any symptoms.

Doctor visits for trich infections (women only) by year

2012 219,000
2013 225,000
2014 155,000
2015 139,000
2016 222,000

Conclusion

Seeing the cold, hard numbers of the impact of STDs on the world can be a sobering and scary thing. But one thing these stats help illustrate is just how common these types of infections are (remember most people who are sexually active will get at least one of these in their lives), which should serve to alleviate the stigma of getting tested — and getting treatment.

Additional References

  • American Sexual Health Association, Statistics. (Undated). Retrieved from http://www.ashasexualhealth.org/stdsstis/statistics/
  • World Health Organization, Sexually transmitted infections (STIs). (2019). Retrieved from https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-(stis)
  • Centers for Disease Control and Prevention, Table 2. Chlamydia — Reported Cases and Rates of Reported Cases by State, Ranked by Rates, United States, 2017. (2018). Retrieved from https://www.cdc.gov/std/stats17/tables/2.htm
  • Centers for Disease Control and Prevention, Table 10. Chlamydia — Reported Cases and Rates of Reported Cases by Age Group and Sex, United States, 2013–2017. (2018). Retrieved from https://www.cdc.gov/std/stats17/tables/10.htm
  • Centers for Disease Control and Prevention, Table 1. Sexually Transmitted Diseases — Reported Cases and Rates of Reported Cases per 100,000 Population, United States, 1941–2017. (2018). Retrieved from https://www.cdc.gov/std/stats17/tables/1.htm
  • U.S. Department of Health and Human Services, Viral Hepatitis in the United States: Data and Trends. (2016). Retrieved from https://www.hhs.gov/hepatitis/learn-about-viral-hepatitis/data-and-trends/index.html
  • Centers for Disease Control and Prevention, Surveillance for Viral Hepatitis – United States, 2016. (2018). Retrieved from https://www.cdc.gov/hepatitis/statistics/2016surveillance/index.htm
  • Centers for Disease Control and Prevention, Prevalence of Herpes Simplex Virus Type 1 and Type 2 in
  • Persons Aged 14–49: United States, 2015–2016. (2018). Retrieved from https://www.cdc.gov/nchs/data/databriefs/db304.pdf
  • Centers for Disease Control and Prevention, Prevalence of HPV in Adults Aged 18–69: United States, 2011–2014. (2017). Retrieved from https://www.cdc.gov/nchs/products/databriefs/db280.htm
  • Centers for Disease Control and Prevention, HPV-Associated Cancer Rates by State. (2018). Retrieved from https://www.cdc.gov/cancer/hpv/statistics/state/
  • Centers for Disease Control and Prevention, HIV Surveillance Report. (2017). Retrieved from https://www.cdc.gov/hiv/pdf/library/reports/surveillance/cdc-hiv-surveillance-report-2016-vol-28.pdf
  • Centers for Disease Control and Prevention, Table 21. Gonorrhea — Reported Cases and Rates of Reported Cases by Age Group and Sex, United States, 2013–2017. (2018). Retrieved from https://www.cdc.gov/std/stats17/tables/21.htm
  • Centers for Disease Control and Prevention, Table 34. Primary and Secondary Syphilis — Reported Cases and Rates of Reported Cases by Age Group and Sex, United States, 2013–2017. (2018). Retrieved from https://www.cdc.gov/std/stats17/tables/34.htm
  • Centers for Disease Control and Prevention, Trichomoniasis Statistics. (2017). Retrieved from https://www.cdc.gov/std/trichomonas/stats.htm
  • Centers for Disease Control and Prevention, Table 44. Selected STDs and Complications — Initial Visits to Physicians' Offices, National Disease and Therapeutic Index (NDTI), United States, 1966–2016. (2017). Retrieved from https://www.cdc.gov/std/stats17/tables/44.htm