Sexually Transmitted Infections


Sexually Transmitted Infections (STIs), sometimes known as Sexually Transmitted Diseases (STDs), are very common in the United States (U.S.) with millions of new infections occurring each year. There are dozens of types of STIs. STIs are passed from one person to another through sexual activity and are preventable with the right preventative measures. STIs may be present in the body with mild to no symptoms, so it is possible to have an infection and not be aware. The ONLY way to know for sure if you or someone else has an STI is to get tested. If you are sexually active or planning to be, getting tested is one of the most important things you can do. If diagnosed with an STI, know that all can be treated with medicine and some can be cured entirely. In the U.S., people who get syphilis, gonorrhea, and herpes often also have HIV, or are more likely to get HIV in the future.

Sexually Transmitted Infections Data Overview

Check out the points below for the main takeaways from this page. 

• In 2018, a total of 1,758,668 chlamydial infections were reported in the U.S., an increase of 2.9% since 2017 (CDC). Highest rates of chlamydia have historically been found in southern NH, but increased rates were more widely dispersed in 2018.

• In 2018, 583,405 cases of gonorrhea were reported in the U.S., an increase of 5% since 2017 and an increase of 82.6% since 2009 (CDC). Hillsborough County, specifically the city of Manchester, bears the highest burden of gonorrhea in NH.

• In 2018, there was 35k cases of syphilis in the U.S., a 14.9% increase since 2017 and a 71.4% increase compared with 2014 (CDC). New infectious syphilis cases in NH were stable between 2012 and 2015, with an increase observed beginning in 2016 and outbreak status declared in 2017. In 2018, NH saw the first case of congenital syphilis since 2013. 

• In 2018, 37,832 people received an HIV diagnosis in the U.S. From 2010 to 2017, HIV diagnoses had decreased 11% in the U.S., however, new diagnoses have increased among some groups, such as injection drug users (CDC). From 2014 to 2018, 25% of persons newly diagnosed with HIV in NH were concurrently diagnosed with AIDS, meaning they received an AIDS diagnosis within 12 months of their first HIV diagnosis. Increases were noted in 2017-2018 in the proportion of new HIV cases in NH reporting injection drug use as an identified risk. 


What is Chlamydia?  

Chlamydia is the most commonly reported STI in the U.S. While chlamydia can infect both men and women, it can cause serious reproductive system damage in women, making it difficult or impossible for them to conceive. Since chlamydia is spread through unprotected vaginal, anal, or oral sex, anyone who is sexually active can contract chlamydia. 

Chlamydia Data Snapshot

The number of infections in women is seen to be much higher than men and highest among adolescents and young adults (15 to 24 years of age) than any other age group. Sexually active young people are at a higher risk due to their common behaviors and biological factors. 


What is Gonorrhea?

Gonorrhea is a very common STI that can infect both men and women. It can cause infections in the genitals, rectum, and throat.  Any sexually active person can get gonorrhea through unprotected anal, vaginal, or oral sex with someone who has gonorrhea. Pregnant women with gonorrhea can also give the infection to her baby during childbirth.

Gonorrhea Data Snapshot

Gonorrhea is very common among young people ages 15 to 24 years of age, with it's highest rates reported in individuals ages 20 to 24 years of age. Gonorrhea is also seen in more men than women. In 2016, NH declared a gonorrhea outbreak with 465 cases in the State, a 250% increase from the previous year. 


The only way for someone to know if they have HIV is to get tested, and the CDC recommends everyone between the ages of 13 and 64 get tested for HIV at least once. People at higher risk should get tested more often. While progress has been made in prevention and treatment efforts, HIV and AIDS remain a persistent problem around the world.

What is HIV?

The Human Immunodeficiency Virus (HIV) weakens a person’s immune system by destroying important cells that fight disease and infection. If not treated, HIV infection can lead to Acquired Immunodeficiency Syndrome (AIDS). There is no effective cure for HIV, but with proper medical care it can be controlled. 

What is AIDS?

AIDS is the late stage of HIV infection that occurs when the body’s immune system is damaged due to the virus. In the U.S., most people with HIV do not develop AIDS because taking HIV medicine every day as prescribed stops the progression of the disease.

HIV/AIDS and Health Equity

Some groups of people in the U.S. are more likely to get HIV than others due to risk factors including their sexual partners, their risk behaviors, and where they live. In the U.S., Blacks/African Americans and Hispanics/Latinos continue to be disproportionately affected by HIV. Blacks/African Americans and Hispanics/Latinos also have higher rates of some STIs than other races/ethnicities, increasing a person’s chance of getting or transmitting HIV. Knowledge of having the disease and stigma associated around care are two major barriers for these groups to receive prevention services and treatment.

Infectious Syphilis

What is Syphilis?

Infectious Syphilis is an STI that if not treated properly, can cause serious health problems including neuralgic (brain and nerve) problems, eye problems, and even blindness. Syphilis can be contracted by direct contact with a syphilis sore during vaginal, anal, or oral sex, and is divided into stages (primary, secondary, latent, and tertiary), all including different signs and symptoms. 

Syphilis Data Snapshot

 In 2017, NH declared a syphilis outbreak, as the number of cases was double that of previous years. Most cases of syphilis are seen among gay, bisexual, and men who have sex with men (MSM). Syphilis among MSM has been increasing for more than a decade. Syphilis is also linked to an increased risk of transmission of HIV infection, as there is a higher proportion of those diagnosed with infectious syphilis that report MSM and/or HIV co-infection compared to those diagnosed with chlamydia and/or gonorrhea. 

Health Equity & Sexually Transmitted Infections

A person's health can be seriously impacted by their race, ethnicity, gender, income level, education and other socioeconomic factors. In regards to sexually transmitted infections...

• African American males have 8.6 times the AIDS infection rate compared to white males and African American females have 18.6 times the AIDS infection rate as white females (Office of Minority Health, HHS).

• African American men are almost 6 times as likely to die from HIV/AIDS compared to non-Hispanic white men and African American women are almost 18 times as likely to die from HIV/AIDS compared to non-Hispanic white women. (Office of Minority Health, HHS).

• HIV continues to be a serious threat to the health of Hispanic/Latinx communities. In 2018, adult and adolescent Hispanics/Latinos made up 27% of the new HIV diagnoses in the United States. (Centers for Disease Control and Prevention). 

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