HIV, STI, & Hepatitis C Facts

Chlamydia & Gonorrhea

Chlamydia and gonorrhea are among the most common sexually transmitted infections (STIs) in the U.S. The CDC estimates that 2.86 million chlamydia and 820,000 gonorrhea infections occur every year. Any sexually active person can become infected with chlamydia or gonorrhea.

Chlamydia is a very common STI, especially among young people. The CDC estimates that almost two-thirds of new chlamydia infections occur among youth aged 15-24 years, and it is estimated that 1 in 20 sexually active females aged 14-24 years has chlamydia. 

Gonorrhea rates across Colorado are skyrocketing. In Tri-County Health Department's jurisdiction of Adams, Arapahoe, and Douglas Counties rates have increased 205%, 206%, and 188% respectively from 2013 - 2017. Statewide, gonorrhea rates have increased nearly 200% over the same time period. Gonorrhea infection is more commonly seen in men, white or Hispanic people, and in people 15 - 24 years of age but any sexually active person can be infected with gonorrhea or other sexually transmitted infections. More information
  1. Transmission
  2. Symptoms
  3. Testing
  4. More Information
Chlamydia and gonorrhea are bacteria that are spread through oral, vaginal, or anal sex with someone who has chlamydia or gonorrhea.

Both men and women may be infected with chlamydia and gonorrhea without knowing it, and as such may transmit the infection to their partners even if they feel fine and don't have any symptoms. 

People with male partners can be infected even if their partner does not ejaculate.

Women who are pregnant and have chlamydia or gonorrhea may pass the infection on to their child during delivery.

People who have received treatment for chlamydia or gonorrhea in the past may become infected again if they have sexual contact with a person infected with chlamydia or gonorrhea. 

The best way to prevent transmission of chlamydia and gonorrhea is to use a condom correctly with every sexual encounter and to be tested for STIs regularly. 


HIV stands for Human Immunodeficiency Virus, and is the virus that can lead to Acquired Immunodeficiency Syndrome (AIDS). The CDC estimates that 50,000 people become infected with HIV each year. Of the 1.2 million people in the United States living with HIV, it is estimated that 1 in 8 people living with HIV don't know they are infected. 
  1. Transmission
  2. Symptoms
  3. Testing
  4. More Information
HIV is a virus that is spread when the blood, semen, vaginal fluid, or breast milk of someone who is HIV+ has direct access to the blood stream or mucous membrane of another person.

According to the CDC in the U.S., HIV is mainly spread the following ways:

  • Having unprotected sex with someone who is HIV+
    • Unprotected anal sex is the highest-risk sexual behavior
    • Unprotected vaginal sex is the second highest-risk behavior
    • Multiple sex partners or having other STIs increases the risk of infection 
  • Sharing needles or injection equipment with someone who is HIV+
The best way to prevent transmission of HIV is to use a condom correctly with every sexual encounter and to be tested for HIV regularly.

People who are at high risk for HIV infection such as men who have sex with men, people who have unprotected sex with multiple partners, and people who have HIV-positive partners can reduce their risk of getting HIV by taking a regular HIV medication (Pre-Exposure Prophylaxis or PrEP). 

Hepatitis C

"Hepatitis" means inflammation of the liver. Hepatitis C is a specific type of hepatitis that is caused by a virus which is transmitted blood-to-blood. The CDC estimates that there are 2.7-3.9 million people in the US with chronic Hepatitis C, and many people don't know they are infected because they don't look or feel sick. 
  1. Transmission
  2. Symptoms
  3. Testing
  4. More Information
Hepatitis C is spread when the blood from a person infected with the virus enters the blood stream of another person.

According to the CDC, common ways that Hepatitis C is transmitted include:
  • Sharing needles or other injection drug equipment
  • Recipient of donated blood or organs in the U.S. before 1992 or anytime outside of the U.S.
  • Needle-stick injuries in health care settings 
  • Mother to child during childbirth
Less common ways of transmission include:
  • Sharing personal items such as a toothbrush or razors
  • Sexual contact with someone infected with Hepatitis C
Page last updated: Sept. 25 2018
Content source: Center for Disease Control and Prevention CDC ChlamydiaCDC GonorrheaCDC HIVCDC Hepatitis C