What are the Most Common Sexually Transmitted Infections?

What are the Most Common Sexually Transmitted Infections?

Created On
Sep 26 2023
Last Updated
Sep 26 2023

Sexually transmitted infections are becoming very common. Here we review some of them, including bacteria and viruses involved in the infection, common symptoms as well as testing and treatment options.


An infection that spreads through sexual contact is called STI (sexually transmitted infection) or STD (sexually transmitted disease).

When one of the partners is already infected, it spreads to the other. And if they have multiple partners, it can spread to many people. Over time, as the newly infected people have sexual relationships with others, the cycle of infection continues to grow. That's why STDs are serious public health problem and affect millions of people. If not tested in time and treated appropriately, they can cause lot of pain, trauma and even loss of pregnancy and infertility.

The cause of infection is often bacteria or viruses, depending on the types of infection. Below we discuss few common STIs, how they spread, the pathogen causing the infection, and recommendations to avoid them.

Types of Sexually Transmitted Infections

There are over twenty different STDs or STIs. Here are the most common ones:


One of the most common STI that might show no or very few symptoms to detect. The cause is a bacterium called Chlamydia trachomatis. Use of protection can prevent the spread but one should test as soon as possible to avoid serious risk to health. Untreated infection can cause infertility and women might get pelvic inflammatory disease (PID). PID can cause pain around pelvis during sex or while peeing and bleeding during sex which can be heavy during menstrual cycle.


Another very common STI caused by the bacterium Neisseria gonorrhoeae. The symptoms might be mild or even delayed for a long time but are very similar to Chlamydia and pelvic inflammatory disease (PID). However, gonorrhea often causes pain while urinating and pus-like discharge. Men might observe pain in testicles and women might notice pain in their lower belly. It is recommended to use protection or test regularly whenever you have or your partner are sexually active outside your relationship.


It is caused by the bacterium Treponema pallidum. Once infected, the disease progresses through four stages. At first, painless sores and warts appear around the groin, genitals, and mouth for 2-3 weeks as the bacteria incubate. As these disappear, the second stage involves rashes on palms of hands and soles of the feet lasting 2-4 weeks. You may see other symptoms including mild fever, swollen glands, body ache, fatigue, sore throat, itching, loss of hair in random patches or weight loss. The third stage is called latent stage without any symptoms for months or even years before returning as the final stage called tertiary syphilis which can lead to serious consequences including damage to heart, brain, liver, eyes, and joints. It can also transfer from mothers to babies. Syphilis is easily treatable with antibiotics but requires testing to confirm an infection.

HPV (Human Papillomavirus)

HPV is the most common STI worldwide. Almost 1 in 6 people is infected with HPV at a given time globally but there is no way to confirm since symptoms are rare and people might not know they are infected. Some people may observe genital warts and women might see abnormal precancerous cells on the cervix. HPV is not a single virus, but a group that can be tested in women with a vaginal swab before it can lead to cervical cancer. There is no cure for HPV, but early testing and regular pep-smears can help detect any infections. HPV vaccines are available and recommended for those under the age of 26 years.


It is caused by the Herpes simplex virus which causes sores and blisters on the mouth (called HSV-1) and genitals (HSV-2). Often flu-like symptoms of chills, fever, body pain also common. There is no cure, but anti-viral medicine can help in potential outbreaks. Safe sex and regular testing can help spread the infection.


HIV is the most famous sexually transmitted virus. Human immunodeficiency Virus attacks the immune system, making it extremely difficult for our body to fight it. If untreated, it can result into AIDS (Acquired Immunodeficiency Syndrome), a serious condition that has killed millions of people over past four decades. Today, antiretroviral therapy and other medical breakthroughs have made it possible to live a normal healthy life. However, protected sex and PrEp (pre-exposure prophylaxis) can effectively avoid spread of HIV.

Hepatitis B and C

These are viral infections that can damage the liver. Besides sexual transmission, they can also spread via blood transfusion and sharing needles (e.g., during drug use). They may not always show any symptoms but often appear as pain in the abdomen region, yellow eyes and skin, dark urine, and fatigue. Hepatitis B can be prevented with vaccination.


Mpox is a relatively new sexually transmitted disease that results in sores and lesions on the body. This viral disease can spread through kissing, touching or sex, especially in men having relationships with other men. A new vaccine is now available and it is easy to get tested for monkeypox.


STDs are huge burden on society due to the pain and suffering they cause. They consume public health resources that can be used elsewhere. The stigma around STDs can prevent people from getting timely diagnosis and treatment. However, it is very easy to get tested for most of them. An easy, simple swab or urine sample collected from the privacy of your home can help one get tested for STDs. RxHomeTest offers multiple options to get tested and seek treatment as early as possible.