STIs What’re? Deep Dive into Risks & Prevention in 2025

In a time when conversations around sex are more open than ever, STIs—Sexually Transmitted Infections—remain an often misunderstood health issue. Many still assume STIs only affect “promiscuous” people or that you’ll always know if you’re infected. The truth?

Most STIs show no symptoms, and many infected individuals don’t even know they carry them. This guide breaks down what STIs really are, which infections to watch for, how they spread, who’s at risk in 2025, and how to protect yourself effectively. Backed by insights from the WHO, CDC, and Thailand’s Department of Disease Control, we’re here to help you stay informed—before it’s too late.

What are STIs?

STIs (Sexually Transmitted Infections) are infections that are primarily transmitted through sexual activities including vaginal, anal, and oral sex. They can also spread via bodily fluids such as semen, vaginal secretions, and blood.

Unlike the term “STD” (Sexually Transmitted Disease), which focuses on the disease stage, STIs emphasize early infection—even when no symptoms are present. For example:

• HPV or herpes can exist silently in the body
• HIV may stay dormant without signs for years

This shift in terminology reflects a more preventative, less stigmatizing public health approach.

Why are STIs a growing public health concern?

Despite Thailand’s historical success in controlling infections—recognized by WHO in 2016 for eliminating mother-to-child HIV/syphilis transmission—recent years show a resurgence:

• Between 2017–2021, syphilis infections among Thai youth aged 15–24 rose 10–15x from prior years.
• In 2021, this age group accounted for 38.81% of all STI cases nationwide

Read more: STIs vs STDs how to difference

What are the health impacts of STIs?

If left untreated, STIs can lead to:

• Infertility
• Ectopic pregnanc
• Chronic reproductive tract infections
• Higher risk of contracting HIV

What Are the Most Common STIs?

Sexually transmitted infections (STIs) include a wide range of pathogens. Here’s a breakdown of the most common ones:

1. Bacterial Infections

• Gonorrhea Caused by Neisseria gonorrhoeae, this infection spreads through sexual contact and may cause painful urination, discharge, or no symptoms at all.
• Syphilis Caused by Treponema pallidum, syphilis progresses through multiple stages if untreated—from painless sores to rashes to neurological symptoms.

2. Viral Infections

• HPV (Human Papillomavirus) One of the most common STIs, spread easily and can cause genital warts or lead to cervical cancer.
• HSV (Herpes Simplex Virus) Causes painful blisters around the genitals or mouth. Spread through skin-to-skin contact or fluid from lesions.
• HIV (Human Immunodeficiency Virus) Weakens the immune system over time, leading to AIDS if untreated.

3. Parasitic & Fungal

• Trichomoniasis Caused by Trichomonas vaginalis, symptoms include foul-smelling discharge, itching, and irritation.
• Candida albicans Not a classic STI, but often linked to sexual behavior; causes yeast infections in the vaginal area.

According to WHO, the top 4 most common global STIs are Gonorrhea, Syphilis, Chlamydia, and Trichomoniasis

How Are STIs Transmitted?

STIs (Sexually Transmitted Infections) are not limited to penetrative sex. Understanding how they spread helps in effective prevention.

1. Sexual Contact

• Vaginal, anal, and oral sex
• Skin-to-skin contact near genitals can transmit infections like herpes or HPV even without penetration

2. Bodily Fluids

• Semen, vaginal fluids, and blood
• Microtears in mucous membranes during sex increase the risk for infections like HIV

3. Shared Personal Items

• Towels, underwear, sex toys, razors
• Though rare, STIs like Trichomoniasis or bacterial infections can spread this way

4. Mother to Child

• During pregnancy, delivery, or breastfeeding
• HIV, syphilis, and herpes are examples of vertically transmitted infections

Who Is at Risk of STIs?

STIs do not discriminate, but certain behaviors and life stages carry higher risks. Here are the key at-risk groups identified for 2025:

1. Teens and Young Adults (Ages 15–29)
   • Globally rising STI rates in this group, especially among those unaware they carry an infection
2. People with Multiple Sexual Partners
   • Risk increases significantly with unprotected sex and lack of mutual screening
3. Inconsistent Condom Users
   • Including couples in long-term relationships who haven’t been tested together
4. People Who Have Never Been Tested
   • Many people assume they’re “safe” despite having past sexual experience without screening
5. Users of Hookup Apps or Discreet Behavior Patterns
   • Not a judgment—but often these situations lack open discussion or awareness of STI status

How Dangerous Are STIs If You Have No Symptoms?

Many people assume: “No symptoms means I’m fine.” But the truth is, many STIs are silent—and during that silent period, you can still pass them on without knowing.

Common Asymptomatic STIs

• Chlamydia: 70% of women, 50% of men show no signs
• HPV: Often invisible, yet increases risk of cervical cancer
• HIV: Can stay dormant for years before showing symptoms

What Can Happen If You Don’t Know You’re Infected?

• Internal damage (e.g., fallopian tube scarring → infertility)
• Unknowingly infecting your partner(s)
• Missing the chance to treat early, when it’s most effective

How to Prevent STIs?

Preventing STIs doesn’t require extreme measures—it requires consistency, communication, and the right choices. WHO and CDC recommend the “ABCD” approach to STI prevention.

A: Abstinence

• Complete sexual abstinence eliminates all risk
• Bet suited for individuals not ready for sexual activity

B: Be Faithful

• Limit sexual partners to one trusted, tested partner
• Open dialogue is crucial for safety in non-monogamous relationships

C: Condom Use

• Use condoms every time, for vaginal, anal, and oral sex
• Female condoms and dental dams are also effective tools

D: Detection

• Get screened regularly—even without symptoms
• If diagnosed, get treated and notify partners for mutual care

STI-Preventing Vaccines

• HPV Vaccine: Prevents genital warts and cervical cancer
• Hepatitis B Vaccine: Part of routine immunization in Thailand

Misconceptions about STIs.

Conclusion

STIs aren’t just a “bedroom issue”—they’re a public health topic that affects everyone, regardless of sex life. Some infections show no symptoms but still impact your body, relationships, and future. If you’ve read this far, this guide was meant to help you see STIs clearly—and act early.

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