4 of the Most Common STDs: What to Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Dec 20, 2024.

Overview of STDs / STIs | Who's at Risk? | Common STIs | HPV | Chlamydia | Trichomoniasis | Gonorrhea | STI Prevention | Join the Support Group

Overview of STDs / STIs

Sexually transmitted infections (STIs) are common, contagious, and spreading widely in the U.S. And it’s not just HIV/AIDS. There are a wide array of highly transmittable and serious STIs for you to be aware of. Prevention, early detection, and proper treatment are key. If you are sexually active, be sure to talk to your healthcare provider about STI testing and which screening tests may be right for you.

• In 2023, over 2.4 million cases of syphilis, gonorrhea, and chlamydia were diagnosed and reported in the U.S. This includes over 209,000 cases of syphilis, 600,000 cases of gonorrhea, and 1.6 million cases of chlamydia.

The good news is that the number of STIs decreased by 1.8% or remained fairly stable in the years 2022 to 2023, with a 7.2% decrease in gonorrhea, a less than 1% change in chlamydia, and a 1% increase in total syphilis cases (including congenital syphilis).

What is the difference between STD and STI?

You may wonder if sexually transmitted infections (STIs) and sexually transmitted diseases (STDs) are the same thing? Sometimes these terms are used interchangeably, but they do have a slightly different meaning. 

• A sexually transmitted infection (STI) is a virus, bacteria, fungus, or parasite that a person can get through sexual contact. This might include STIs like chlamydia, gonorrhea or syphilis.
• A sexually transmitted disease (STD) develops due to an STI. STD means that the infection has led to symptoms of the disease.
• STD used to be used more commonly, but the CDC denotes that the public health goal is to prevent and treat STIs before they develop into STDs, so STI is now the preferred term. STD can still be used when referring to data or information from sources that use this term.

Who is most at risk for STDs / STIs?

Young people ages 15 to 24 make up the largest group that contract STIs, roughly about 50% of all new cases.

• In 2023, about 48.2% of reported cases of chlamydia, gonorrhea, and syphilis (all stages) were among adolescents and young adults aged 15–24 years. 
• Also, gay, bisexual and other men who have sex with men (MSM) are disproportionally impacted by STIs, including gonorrhea and primary and secondary (P&S) syphilis, and co-infection with HIV is common. About one-third of these cases occur in non-Hispanic Black or African American.

In addition, many young people do not realize they have an STI, as many infections have few, if any symptoms. When you’re not aware you have a sexually transmissible disease, you are more apt to spread it through unprotected sexual contact. The consequences of untreated STIs are often worse for young females, as it can affect fertility.

If you find out you have an STI, also get tested for HIV. CDC recommends that everyone between the ages of 13 and 64 get tested for HIV at least once as part of routine health care. For those at higher risk, CDC recommends getting tested more often, typically at least once per year.

Sexually active gay or bisexual men may benefit from more frequent testing (every 3 to 6 months). Talk to your health care provider about your risk factors and what testing schedule and options may be best for you.

4 Common STDs / STIs

• Human Papillomavirus (HPV)
• Chlamydia
• Trichomoniasis
• Gonorrhea

Chlamydia, trichomoniasis and gonorrhea are easily treated if caught early, but that’s not always the case, and HPV can prevented with a vaccine. Read here to learn how to recognize the symptoms that may be linked with these STIs, and what action you should take.

1. Human papillomavirus (HPV)

You may be familiar with this STI due to the news around the HPV vaccine to help prevent HPV-related cancer. 

• Over 42 million Americans are infected with types of HPV that are known to cause disease.
• About 13 million Americans, including teens, become infected each year.
• The human papillomavirus (HPV) is one of the most common sexually transmitted infection in the U.S. 

How do you get HPV?

HPV is a virus almost everyone catches at some point or another. You can get HPV by having vaginal, anal, or oral sex with someone who has the virus. Some types cause few symptoms and no medical problems, while others can lead to serious concerns like genital warts, cervical cancer and oropharyngeal cancer (cancer of the throat).

• HPV can cause cervical and other cancers including cancer of the vulva, vagina, penis, or anus. Every year, HPV causes about 36,000 cases of cancer in both men and women in the U.S.
• It can also cause cancer in the back of the throat, including the base of the tongue and tonsils (called oropharyngeal cancer).
• It takes roughly 20 to 25 years for a new HPV infection to cause cervical cancer. That is why regular screening with a Pap, HPV or both tests is important.

Can you be screened for HPV?

Females should undergo routine cervical cancer screening (Pap test) between ages 21 and 65 years of age. An HPV DNA test can identify certain HPV types on a woman’s cervix and may be used with a Pap test. Even females who are vaccinated need cervical screening. You will need to repeat your Pap test every 3 or 5 years.

After age 65, you may be able to stop Pap test based on your health history and risk factors. Discuss this with your healthcare provider.

There is no approved routine HPV test for men.

How is HPV prevented?

Vaccination can protect both females and males from HPV, and the resultant cancers caused by HPV, including cervical cancer. HPV vaccination is most effective if started before the individual gets infected with HPV and before they have sex for the first time. 

Gardasil 9 vaccine

There are several HPV vaccines. In the U.S., the one available since 2016 is known as Gardasil 9.

• Gardasil 9 vaccine prevents genital warts and cancers caused by nine different subtypes of HPV.
• It is used in both males and females from ages 9 through 45 years of age.
• Gardasil 9 is given as an intramuscular (IM) injection in a 2- or 3-dose series, depending upon age.

Take away points

The CDC recommends HPV vaccine for all boys and girls ages 11 to 12 years old. It can be started as early as 9 years of age. If the HPV vaccine is started before age 15, two doses (6 months apart) can be used instead of three doses.

In adolescents and adults 13 to 26 years old who have not had the vaccines or who have not completed the vaccine series, catch-up vaccination is recommended. If you are younger than 45 years of age, discuss with your doctor or pharmacist if Gardasil-9 is right for you.

If you have not been vaccinated, reduce your risk of genital HPV by using latex condoms; however, the throat and other exposed skin areas may still be at risk for HPV. Genital skin-to-skin contact may increase risk. A monogamous (same person) relationship with a disease-free partner can help to prevent HPV if you are not vaccinated.

Genital warts can be treated with locally applied medications that destroy the tissue, freezing (cryotherapy), or surgical removal. Cancers may not be caught until screening.

See Also: HPV Support Group

2. Chlamydia

Chlamydia is the most common “reportable” STI in the U.S. In 2023, a total of 1,648,568 cases of Chlamydia trachomatis infection were reported. Reportable STIs must be documented to the local health departments when it is diagnosed to help track trends and control future outbreaks.

Rates of reported chlamydia were highest in 2023 among adolescents and young adults ages 15 to 24 years of age, at about 56% of cases.

How do you get chlamydia?

Chlamydia is spread via oral, anal, or vaginal sex. Gay, bisexual, and other men who have sex with men are also at risk since chlamydia can be spread through oral and anal sex.

Most people with chlamydia do not show symptoms. Symptoms of chlamydia in men include discharge from penis, burning urination, testicular pain and swelling. In females, burning urination and vaginal discharge can occur. Chlamydia can affect the rectum as well, with symptoms of rectal pain, discharge, and bleeding.

Can you be screened for chlamydia?

Sexually active females under 25 years of age should be screened for chlamydia and gonorrhea each year, as well as females 25 years of age and older at increased risk for infection (such as with new or multiple sex partners), per the U.S. Preventive Services Task Force (USPSTF). This includes pregnant females.

According to some clinicians, gay, bisexual, and other males who have sex with males should also get tested for chlamydia. In some cases, more frequent testing may be needed in other high risk groups.

However the USPSTF states there's not enough clinical data to weigh the risks and harms to determine if screening for chlamydia in men is warranted. They say more studies are needed.

How is chlamydia treated?

Chlamydia can be tested for and easily treated with antibiotics, but you can still get it again. If untreated, chlamydia can affect a woman's ability to get pregnant due to ongoing pelvic inflammatory disease.

Oral doses of azithromycin (Zithromax) and doxycycline (Vibramycin) are commonly used to treat chlamydia. Pregnant females should not use doxycycline. Azithromycin is the easiest because it is given as a one-time dose.

Do not have sex for week after finishing your medicine to help prevent a re-infection. 

If you are infected with chlamydia, you may also be infected with gonorrhea, so your doctor will test and treated for both STIs, if needed. They can be tested for on the same specimen at the same time.

It’s important your partner is treated, too. Your doctor may give you prescriptions for both you and your partner. Wait 7 days after you and your partner have been treated to have sex again.

Take away points

Symptoms may not always be present, so testing for chlamydia may be needed with new partners. Condom use can lower the risk for getting chlamydia.

Chlamydia can cause pelvic inflammatory disease. If left untreated, chlamydia can affect a woman’s reproductive system and make it difficult or impossible to get pregnant in the future.

If you are pregnant, you can give chlamydia to your baby during childbirth. Get tested at your first prenatal visit.

To help prevent chlamydia, use a male latex condom each time you have sex, get all sexual partners (within the last 60 days) treated (even if they don't have symptoms), do not have sex if you have chlamydia symptoms, and schedule a doctor appointment to be checked if you do have symptoms. Don't have sex if you or your partner have any discharge, burning with urination, or a genital rash or sore.

See Also: Chlamydia Infection Support Group

3. Trichomoniasis

Trichomoniasis (often called “trich” for short) is a common sexually transmitted disease. It's caused by infection with a parasite called Trichomonas vaginalis. In the U.S., about 2 million people had the infection in 2018, the latest numbers from the CDC.

How do you get trich?

You can get trich by having sex without a condom with a partner who is infected. Trichomoniasis can increase the risk of spreading other STIs, such as HIV. Pregnant females are at risk for preterm or low-weight babies.

As with many STIs, people with trichomoniasis often have no symptoms. Only about 30% of people develop any symptoms. But luckily for anyone who contracts this infection, trichomoniasis is considered one of the most easily curable STIs. All sex partners should get treated with antibiotics at the same time to help avoid a re-infection.

In those that develop symptoms, itching, redness, burning after urination, or an unusual discharge may occur in the vagina or around the vulva in females and in the penis for males. Symptoms may develop within one to four weeks, or may not develop until later. Sex can be uncomfortable.

Can you be screened for trich?

A physical examination and lab work by your doctor can diagnose trichomoniasis.

How do you treat trich?

Treatment is given whether symptoms are present or not if trichomoniasis is detected.

Preferred treatment for trichomoniasis is with a 7-day course of either oral metronidazole (Flagyl) or tinidazole (Tindamax), instead of single dose therapy, due to better overall cure rates and better tolerability. Single-dose oral secnidazole (Solosec) is also an option but it is expensive and not available generically.

Single-dose therapy is often used as initial treatment in males. In females, cure rates may not be as high with single dose treatment.

Oral metronidazole is an option for pregnant females or females with HIV; a 7-day course is often preferred but a single day dose is an option. Treatment with metronidazole vaginal gel is not effective for trichomoniasis.

Partners should also be treated. Wait 7 days after you and your partner have been treated, and symptoms are gone, to have sex again.

Depending upon which medicine you take, you may need to avoid consumption of alcohol for 24 to 72 hours after treatment to help reduce side effects. Follow the directions provided on your bottle and ask your doctor or pharmacist.

Your may ask you to retest you for trichomoniasis 2 weeks to 3 months after treatment to be sure you have not been reinfected.

Take away points

About 70% of infected people do not have any signs or symptoms, so it’s often hard to know if you or your partner have the infection. It can be spread during sex in males and females. People with trich can pass the infection to others, even if they do not have symptoms.

Without treatment, the infection can last for months or even years.

Trichomoniasis screening should be conducted at least annually for all HIV-infected females.

See Also: Trichomoniasis Support Group

4. Gonorrhea

Gonorrhea (from Neisseria gonorrhoeae) is a sexually-transmitted bacterial infection that commonly occurs in younger people between the ages of 15 and 24. It can lead to infection the genitals, rectum, and throat, but it can be cured with antibiotics. About 700,000 people in the U.S. are infected each year. 

Both females and males with gonorrhea are at risk of developing serious complications, including infertility. A pregnant person may also transmit the infection to their child during childbirth. 

How do you get gonorrhea?

Gonorrhea is spread during oral, vaginal / penile, or anal sex between partners. You can't be infected with gonorrhea by touching objects like a toilet seat.

Your risk of getting gonorrhea is greater if you have a new sexual partner, more than one sexual partner, or if you have other sexually transmitted infections.

Symptoms are not always present in people with gonorrhea. In fact, many men and most females do not usually have symptoms.

Symptoms of gonorrhea may include:

• • burning or pain while urinating
  • discharge from the penis (milky-colored)
  • vaginal itching or discharge
  • swollen or painful testicles in men
  • vaginal bleeding or spotting between periods in females
  • rectal gonorrhea symptoms may include discharge, anal itching, soreness, bleeding, constipation and painful bowel movements.
  • a throat infection usually has no symptoms, but can cause a sore throat.

Can you be screened for gonorrhea?

Your doctor can diagnose gonorrhea using a urine sample or a swab from the throat, rectum, or genitals.

The CDC recommends yearly gonorrhea (and chlamydia) screening for all sexually active females younger than 25 years, as well as older females with risk factors such as new or multiple sex partners, or a sex partner who has an STI. Screening high-risk females at the first prenatal visit in pregnancy is recommended, as well.

In sexually active gay men, bisexual men, and other men who have sex with men (MSM) screening for gonorrhea (as well as syphilis and chlamydia) is recommended at least once a year per the CDC. Those who have multiple or anonymous partners should be tested more frequently (e.g., every 3 to 6 months).

How do you treat gonorrhea?

Gonorrhea can be hard to treat due to drug-resistant bacteria. In addition, a delay in treatment can result in serious medical complications. Not only does untreated gonorrhea increase a person’s risk of getting HIV, but it can also lead to pelvic inflammatory disease (PID) in females. PID can lead to infertility and increase the risk of having pregnancy complications. 

• Ceftriaxone is the treatment of choice for uncomplicated gonorrhea. Due to increasing levels of drug resistance, treatment now involves a single 500 mg intramuscular (IM) ceftriaxone injection.
• For individuals who weigh ≥150 kg (>300 lb), a 1 gram IM dose of ceftriaxone is suggested.
• You should not have sex until 7 days after your treatment. Your partners should also not have sex until seven days after treatment. 
• Treatment is the same for both males and females.

Most states allow prescribers to provide prescriptions for gonorrhea treatment (and other select STIs) to be delivered to a partner by the patient. This is known as expedited partner therapy (EPT). Co-treatment of the other sex partner at the time of first diagnosis is necessary to prevent reinfection. Discuss this important action with your doctor.

Ceftriaxone plus oral azithromycin (Zithromax) is no longer recommended, per the CDC. In addition, cefixime is not a preferred agent for the treatment of gonorrhea due to increasing reports of drug failure. New treatment options for gonorrhea are actively under research.

Treatment for chlamydia should also be instituted when needed, as this infection commonly occurs with gonorrhea.

Take away points

Ask your doctor if you need to return to the medical office to be tested again after your treatment (called "a test of cure "). It is possible to be infected with gonorrhea more than one time or for your antibiotic to not fully cure your infection.

If your symptoms continue for more than a few days after your treatment, return to your health care provider to be seen.

Re-infection is common with gonorrhea. Therefore, your doctor may want you to be retested 3 months after your initial treatment, even if your partners have been successfully treated.

See Also: Gonorrhea Support Group

What should I consider in preventing STDs / STIs?

Prevention is key with STIs, but it’s not an easy task. Think hard before engaging in sex with someone unfamiliar to you whose sexual history you do not know. Discuss the possibility of STI testing with your partner prior to an initial sexual encounter, and keep condoms within reach.

Schedule an appointment with your doctor to be screened for STIs, and consider you may need to repeat these if you have multiple sexual partners. While medication treatment is easy with some STIs, others can be more involved, require surgery, or lead to fertility problems, in both females and men. 

People who have had oral or anal sex should talk with their healthcare provider about throat and rectal testing options.

Talk to your doctor about vaccines that can prevent STIs: currently, the HPV vaccine, Hepatitis A, and Hepatitis B vaccines all work to prevent STIs. Other vaccines, like an HIV vaccine, remain under study.

Take away points:

• The only sure way to prevent getting or spreading an STI is to avoid sex or stay in a monogamous relationship with a disease-free partner. However, this cannot always be assured.
• Using a latex condoms correctly each time you have sex can be useful to help prevent STIs, but are not always 100% effective either.
• Speak with your partner before your first sexual encounter to determine the level of risk you are comfortable with, and consider testing for each person prior to having sex the first time.
• If questions arise, always consider speaking with a healthcare provider who can provide confidential advice.

Still have questions and want more answers?

Consider joining the Drugs.com Sexually Transmitted Diseases Support Group to discover others with similar conditions and related medications, read more up-to-date news, and share your own experience, too.

Learn More About STDs / STIs

• Treatment of STDs / STIs
• Sexually Transmitted Diseases: Overview

Further information

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