How Common Are STIs?

Patient Presentation
An 18-year-old male came to clinic for his health supervision visit. His past medical history showed that he was generally healthy and had all of his immunizations. During the social history he denied using alcohol, drugs, tobacco or being sexually active. The pertinent physical exam showed a healthy male with normal vital signs and BMI of 22.2, He was Tanner stage V and the rest of his examination was negative.

The diagnosis of a healthy male was made. The pediatrician recommended for him to receive his second Group B Meningococcal vaccine along with an updated tetanus vaccine as he was going to be working in construction and gardening over the summer. He said, “We also are screening all adolescents for HIV at your age. I know that you said you have not been sexually active but it is still recommended. The most important part is two-fold. One, the best way wait to prevent sexual infections and pregnancy is not to have sexual relations. So I recommend that you continue your current lifestyle. Two, if you do decide to become sexually active, use condoms each and every time along with some type of spermicide. That is also another good option to help prevent pregnancy and infections.” The physician discussed and gave the teen a handout on how to properly use a condom and when to have sexually transmitted infection testing (STI). “I always think its best to have all the information. Besides you can also keep this information for later or give it to a friend who might need it,” he remarked.

Of the 30 different microbes which can be transmitted by sexual contact, 8 have the greatest incidence of transmitting disease. Four are curable (Chlamydia, Gonorrhea, Syphilis and Trichomoniasis) and 4 are incurable at present (Hepatitis B, Herpes simplex virus (HSV), Human immunodeficiency virus (HIV) and Human papillomavirus (HPV)).
Sexually transmitted infections (STIs) are important as they can cause:

  • Increased rates of acquisition of other STIs (ie HSV and syphilis increase the rate of HIV infection acquisition)
  • Pelvic inflammatory disease and infertility
  • Stillbirth and neonatal death
  • Neonatal morbidity including low-birth weight, prematurity, conjunctivitis, pneumonia, sepsis, and congenital abnormalities
  • Genital cancer

In high-income countries diagnosis usually includes laboratory testing and then treatment. Short-course antibiotic treatment for curable infections is effective. In low- and middle-income countries laboratory testing is often cost prohibitive and the diagnosis is made by syndromic management using symptoms and guidelines to direct care. Syndromic management is good as patients can be treated the same day, but the majority of STIs are not detected because patients are asymptomatic. Preventative vaccines for Hepatitis B and HPV have and are showing high prevention rates. Other vaccines are also being developed. Other interventions show that male circumcision decreases the risk of heterosexually transmitted HIV infection and may provide some protection against other STIs. A vaginal microbicide called Tenofovir may have some efficacy against HIV and HSV prevention.

STI screening guidelines from the Centers for Disease Control (CDC) can be found here. 2016 STI treatment guidelines from the CDC can be found here.

Learning Point
The World Health Organization estimates that more than 1 million STIs are acquired daily with 357 million new infections of one of the 4 curable STIs occurring each year. An additional 500 million people are living with HSV and another 290 million women have HPV.

The United States saw an increase in STIs in 2015. It is estimated that 20 million new STIs occurred in 2015 with more than 50% of them in the adolescent/young adult population (age 15-24 years). The large increase in Chlamydia and Gonorrhea were in this age group. There is also an increase in Syphilis reported among men, particularly those who are bisexual or gay.

Total STIs by World Region from the World Health Organization Reported in 2016

Location Total STIs
Americas 64 Million
Africa 60 Million
Eastern Mediterranean 31 Million
Europe 18 Million
South-East Asia 39 Million
West Pacific 142 Million

STIs by Age Range in the United States Reported to the Centers for Disease Control in 2015

Location Total STIs Chlamydia Gonorrhea Syphilis
Age 0-14 years N.A. 11,308 2,538 Primary and secondary 12, Congenital syphilis 487, increase 6%
Age 15-24 years N.A. 981,359 increase 2.5-4.2% 196,593 increase 5.2-7.2% Primary and secondary 5,966 increase 10.2-14.9%
Total 20 Million 1,526,658 increase 6% 395,216 increase 13% Primary and secondary 23,872 increase 19%

Increased rates are from 2014 to 2015, ranges are given if more than 1 age group is included. N.A. is not available

Questions for Further Discussion
1. What are the 5P’s of screening in a sexual health history?
2. How is teenage confidentiality handled in your practice regarding sexual health?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Sexually Transmitted Diseases.
To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

CDC Fact Sheet. Reported STDs in the United States. 2015 National Data for Chlamydia, Gonorrhea, and Syphilis.Available from the Internet at (rev. October 2016, cited 5/2/17).
Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2015. Atlanta: U.S. Department of Health and Human Services; 2016.

World Health Organization. Sexually Transmitted Infections (STIs) Fact Sheet. Available from the Internet at (rev. 8/2016 cited 5/2/17).
World Health Organization. Global Health Sector Strategy Sexually Transmitted Infections 2016-2021. Available from the Internet at (rev. 6/2016, cited 5/2/17).

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa