A service provided by the BC Centre for Disease Control

Close

Search

Home / All About STIs / STI Basics / Know Your Chances

Know Your Chances

It is common to have questions or feel concerned about sexually transmitted infections (STIs). The chances of getting or passing an STI to partners can depend on a few things:    

1)  Do you or your partner(s) have an STI?

Many STIs do not show symptoms, and people can have an STI without knowing it. Getting tested is the only way to know if you have an STI. How someone looks, the partners they have, and other assumptions about a person’s lifestyle are not good ways to tell if someone has an STI. Your partner(s) would have to have an STI to be able to pass it to you.

2)  Are you using any safer sex methods, such as condoms, vaccines or medication?

3)  What kind of sex are you having?

Body fluids like blood, semen/cum, vaginal fluid, rectal fluid and breastmilk can pass some STIs. Others are passed through skin-to-skin contact during sex. Fluids like sweat, tears, saliva and urine do not pass STIs.

To learn more about STIs and how they are passed, you can find more in our STIs at a Glance chart, and to learn more about how different sexual activities pass some STIs read the My Chances charts below.

How to Lower Your Chances of Getting an STI

My Chances

The content below can give you an idea of which sexual activities are more or less likely to pass an infection to you if your partner has that infection. Some STIs are more common than others. You are less likely to get an infection that is not very common, even if the infection can be passed that way. The actual chances of an STI being passed are unique to each infection and personal circumstances. The table is based on published research and reviewed by STI experts in British Columbia. It does not cover every situation or STI.  Some important considerations:

  • Sometimes condoms can break or slip. If this happens, the chances of getting an STI are the same if no condom was used. Condoms are not as good at preventing infections passed by skin-to-skin contact such as syphilisherpes and HPV.
  • People living with HIV can take medication to lower the amount of virus in their blood to a very low level. This is called undetectable viral load, and it means that HIV cannot be passed to others through sexual activities (also called Undetectable = Untransmissible, or U=U).
  • Pre-exposure prophylaxis (PrEP) is medication that you can take daily, or as prescribed to lower your chances of getting HIV.

What the chart means:

Not passed: this infection cannot be passed between people by this kind of sex

Not likely to be passed: this is not a common way to pass the infection, and would only be possible under the right conditions

Could be passed: this type of sex can pass the infection under the right conditions

Easily passed: this infection is commonly passed between people by this kind of sex

Genital or Anal Sex

Not passed

Not likely to be passed

Green dot

Could be passed

Green dot

Easily passed

Penis in Vagina (Vaginal Sex)

No condom

 

Chlamydia

Easily passed

 

Gonorrhea

Easily passed

 

HIV

Could be passed

 

Herpes

Easily passed

 

Syphilis

Easily passed

 

HPV

Easily passed

With condom

 

Chlamydia

Not likely to be passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not likely to be passed

 

Herpes

Could be passed

 

Syphilis

Could be passed

 

HPV

Could be passed

Penis in Anus (Anal Sex)

No condom

 

Chlamydia

Easily passed

 

Gonorrhea

Easily passed

 

HIV

Easily passed

 

Herpes

Easily passed

 

Syphilis

Easily passed

 

HPV

Easily passed

With condom

 

Chlamydia

Not likely to be passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not likely to be passed

 

Herpes

Could be passed

 

Syphilis

Could be passed

 

HPV

Could be passed

Genital Contact, Skin-to-Skin

Sharing body fluids

 

Chlamydia

Not likely to be passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not likely to be passed

 

Herpes

Could be passed

 

Syphilis

Could be passed

 

HPV

Could be passed

No sharing body fluids

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Could be passed

 

Syphilis

Could be passed

 

HPV

Could be passed

Oral Sex

Not passed

Not likely to be passed

Green dot

Could be passed

Green dot

Easily passed

Mouth on Vagina

No barrier

 

Chlamydia

Not likely to be passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not passed

 

Herpes

Easily passed

 

Syphilis

Easily passed

 

HPV

Easily passed

With barrier

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not likely to be passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Mouth on Penis

No condom

 

Chlamydia

Easily passed

 

Gonorrhea

Easily passed

 

HIV

Not passed

 

Herpes

Easily passed

 

Syphilis

Easily passed

 

HPV

Easily passed

With condom

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not likely to be passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Mouth on Anus (Rimming)

No barrier

 

Chlamydia

Not likely to be passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not passed

 

Herpes

Easily passed

 

Syphilis

Easily passed

 

HPV

Easily passed

With barrier

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not likely to be passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Deep Kissing with Tongue

 

Chlamydia

Not passed

 

Gonorrhea

Not likely to be passed

 

HIV

Not passed

 

Herpes

Easily passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Other kinds of sex

Not passed

Not likely to be passed

Green dot

Could be passed

Green dot

Easily passed

Sharing Sex Toys

No condom / not cleaned between

 

Chlamydia

Could be passed

 

Gonorrhea

Could be passed

 

HIV

Could be passed

 

Herpes

Could be passed

 

Syphilis

Could be passed

 

HPV

Could be passed

With condom / cleaned between

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not passed

 

Syphilis

Not passed

 

HPV

Not passed

Hand on Penis or Vulva (Handjob)

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not likely to be passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Fingers in Anus or Vagina (Fingering)

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not likely to be passed

 

Syphilis

Not likely to be passed

 

HPV

Not likely to be passed

Masturbation

 

Chlamydia

Not passed

 

Gonorrhea

Not passed

 

HIV

Not passed

 

Herpes

Not passed

 

Syphilis

Not passed

 

HPV

Not passed

A Note on Gender Diversity and Language

Everyone’s anatomy is a little different and people use different words to describe their bodies. We use common terms to describe genital anatomy (ie. penis and vagina), but ultimately it is the type of sexual contact and body fluids involved that determines whether STIs can be passed rather than anatomy. Gender affirming surgery may change which STIs which tests are recommended in some cases. For more information talk to your provider or visit Transcare BC.

If You or Your Partner(S) is Living With an STI

If you or your partners are being treated for an STI, wait until you have both finished the medication and follow the advice of your health care provider about when you can have genital, oral, or anal sex.

For infections that can be managed, but not treated, such as HIV or herpes, there are medications that can lower your chances of passing on the infection.

There are ways to keep you and your partner(s) healthy, while having an enjoyable sex life.

Still Have Questions?

If you still have questions about your personal situation or risk, you can:

  • Get more information. We have more information and links below, as well as other resources on this website. You can also search our Answered Questions Library to public questions answered by our sexual health nurses.
  • Ask a question. You can use Options for Sexual Health’s Sex Sense service to have your specific questions answered over the phone or email. Sex Sense cannot be used to diagnose or provide medical care.
  • Talk to a health care provider. Use the clinic finder to locate services, or use HealthLink BC’s 8-1-1 service to discuss your concerns if you don’t have a regular or trusted health care provider.