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Preventing STIs

Practicing safer sex is a good way to lower your chances of preventing unwanted pregnancy, getting a sexually transmitted infection (STI), or passing one on to a partner. We recommend you find out what works best for you and your partners.

Preventing STIs

An STI is caused when a bacteria, virus, or parasite is passed from one person to another during sexual contact. Some kinds of sex have a lower chance of passing STIs. For example, the chance of passing an STI is much less with mutual masturbation than with unprotected genital sex. 

There are a number of ways to lower your chances of getting or passing an STI:

Barriers:  When used correctly, barriers like condoms, dental dams, and gloves lower the chance of STIs.  However, barriers don’t work for everyone. For some people, condoms can reduce sensation or make it difficult to get or keep an erection. An internal condom (sometimes called “female” condom) can sometimes help with this.



There are external condoms (sometimes called “male” condoms) and internal condoms (sometimes called “female” condoms). When used properly, they can prevent many sexually transmitted infections (STIs) and pregnancy.

A new condom should be used every time you have sex, with each new partner, and when switching from anal to oral or genital penetration. The condom should be applied before sexual contact occurs.  Condoms can be used with sex toys. 

External condom

The external condom is made of thin latex that fits snugly over the penis/external genitals. There is a tip at the top to hold ejaculate (cum).

Condoms made of latex or non-latex (ie nitrile, polyurethane and polyisoprene) are highly protective against many STIs. Do not use condoms with the spermicide nonoxynol-9 as it can cause irritation and increase the chance of getting HIV. Lambskin or sheepskin condoms protect against pregnancy, but are not effective for preventing STIs, including HIV. Novelty condoms, such as “edible” condoms, do not offer protection against either STIs or pregnancy.

Some STIs, such as herpes and HPV (which causes genital warts), are passed by skin-to-skin contact. While external condoms provide good protection, they don’t cover all areas, and therefore may not always prevent infection. Dental dams and internal condoms can cover a larger area. 

You can buy condoms at most drug stores, corner stores and grocery stores. Sexual health clinics often have free external condoms available to the public.

How to use an external condom: 

  • Check the expiry date on the package. Be careful not to tear the condom when taking it out of the packet.
  • Add a drop of water-soluble or silicone lubricant to the inside of the condom if you like.
  • Check to see which way the condom rolls and put the condom on the end of the erect penis/external genitals.
  • Pinch the tip of the condom to remove the air in the tip.
  • Unroll the condom down to the base of the penis/external genitals.
  • After intercourse, withdraw the penis/external genitals before it becomes soft; hold the condom to make sure that semen does not spill out.
  • Slide the condom off the penis/external genitals, tie the open end in a knot and throw it in the garbage.

Condoms that fit well will feel better and are less likely to fall off or break. There are many styles and sizes of condoms, so it’s a good idea to try different ones to decide what works for you. Keep condoms in a cool, dry, dark place. Heat, light and moisture break down condoms and increase the risk of breakage. Find out what to do if a condom breaks.


Internal condom

The internal condom is made from synthetic nitrile, a type of material that is thinner than latex but stronger so less likely to break. It fits inside the vagina/internal genitals or inside the rectum. The internal condom is a good option for people who are sensitive or allergic to latex. It can be useful for those with a sexual partner who has difficulty maintaining erections or have soft erections. It can also be useful for those who need to rest during sex because of long sex sessions, ability, or stamina.

Reasons some people prefer the internal condom:

  • It gives more STI protection than the external condom because part of the condom stays outside the body and covers more of the skin around the genitals.
  • It can be put into place up to 2 hours before intercourse and it does not need to be taken out immediately after intercourse.
  • It can be used for both genital and anal sex. Note that it has not been approved for anal sex (this is considered “off label” use).
  • It can be used with any type of lubrication.
  • It is not affected by temperature or humidity and has a shelf life of 5 years.

Internal condoms are not widely available at drug stores or grocery stores, but are sold at some speciality sex shops. Internal condoms are more expensive than external condoms, but can be available for free at some sexual health clinics.

How to use an internal condom

There are two ways to use the internal condom. It can be put over the erect penis/external genitals before having intercourse or it can be inserted into the vagina/internal genitals or anus before intercourse.

  • Find a comfortable position, lying, sitting or standing with one foot raised.
  • Hold the smaller ring (at the closed end) and squeeze it between the thumb and middle finger.
  • Put it into the vagina/internal genitals or anus, pushing it inside as far as possible; the outer ring will stay outside the body.
  • Make sure that the penis/external genitals is directed inside the condom and not to the side of it.
  • During sex, the outer ring will lie flat against the body when the penis/external genitals enters the vagina/internal genitals or anus.
  • Soon after sex, twist the condom and gently pull it out, making sure that no ejaculate is spilled.
  • Tie it in a knot and put it in the garbage.

It’s rare for internal condoms to break, but can be possible if the penis/internal genitals are pushing against the end of the condom. 

Condoms and oral sex

Condoms are recommended for oral sex because some STIs, including herpes, gonorrhea, chlamydia and syphilis, are easily passed during oral sex. An external condom can be used when performing oral sex on the penis/external genitals. To make a condom into a dental dam (for cunnilingus or rimming), cut it lengthwise and hold it against the vagina/external genitals or anus. 

Flavored condoms

Flavoured external condoms are colorful latex condoms that come in a variety of flavours. They are popular for oral sex because some people do not like the taste of regular condoms.

It is safe to use flavoured condoms for oral sex. The flavoring and colors added to these condoms are the same additives that are used in food products and are safe to swallow.

The safety of using flavoured condoms for genital or anal sex is not well studied. It is possible that some ingredients used in flavored condoms may cause vaginal irritation, yeast infections or bacterial vaginosis.

Some tips for pleasure and condoms

Condoms come in different styles and textures to increase sensation and pleasure. For example, condoms can be part of foreplay when you have partners put it on or in. Studies show that with regular use, you will notice the condom less and the pleasure more. Keep condoms nearby so that they are easy to use when you need them.

Sometimes, people lose their erections or find they are not able to ejaculate when using external condoms. Here are some things you can try:

  • Masturbate with a condom to get used to the sensation.
  • Masturbate until close to ejaculation (cumming), then put the condom on and finish.
  • Do all the things you like to do sexually, but with a condom on; focus on what feels good.
  • Use water-soluble lubricant (lube) on the inside and outside to improve sensation.
  • Use an internal condom.



Toward the Heart – Search by city or postal code to find clinics in BC that provide free safer sex supplies

Avert.org – Using condoms, types and sizes

Avert.org – The internal condom

Dental Dams and Other Barriers:

A dental dam is a piece of thin latex that is placed over the vagina/internal genitals or anus during oral sex. It can also be called a latex barrier/sheet, latex dam, oral dam or sheet.

Dental dams are a good way to lower the chance of getting or passing sexually transmitted infections (STIs). 

They are usually available in pharmacies, medical supply stores, sex shops and sexual health clinics. Supplies can also be ordered online. An external condom cut length-ways can be used in the same way as a dental dam.


How to use dental dams

  • Before you use the dam, hold it up to light and check for holes
  • Rinse it gently with warm water to remove powder
  • Hold the dam over the vagina/internal genitals or anus
  • Be sure that only one side of the dam touches the vagina/internal genitals or anus
  • Use a new dam each time you have oral sex
  • Use a different dam for the anal area and the vagina/internal genital area
  • Use lubricant on the vagina/internal genitals or anus to improve sensation
  • Dispose of the dam in the garbage.

Non-microwaveable plastic food wrap is sometimes used in place of a dental dam. These products have not been tested for STI protection.



Island Sexual Health Society – Using dental dams for safer oral sex

Halifax Sexual Health Centre – How to use and make a dental dam from a condom and from a glove


It is possible to lower the chances of getting or passing HIV by taking antiretroviral medication.

People living with HIV can take medication (HAART) to reduce the amount of virus in their body (viral load) and lower the chance of passing HIV to a partner. 

People who are HIV negative can also take medication to lower their chance of getting HIV. Medication taken before exposure (pre-exposure prophylaxis, or PrEP) or soon after exposure (post-exposure prophylaxis, or PEP) can prevent a person from getting HIV.


Other medications that prevent STIs include:

  • HPV vaccine: stops genital warts and some strains of HPV that cause cancer.
  • Antiviral medications: reduce the chance of passing on herpes.
  • Hepatitis A and B vaccines.


Hepatitis A and B and some types of Human Papillomavirus (HPV) can be prevented by vaccines. Vaccines for some other STIs, including HIV and Herpes Simplex Virus (HSV) are being developed.

Vaccines are made from weakened or killed bacteria or virus. When a person is given a vaccine, the body’s immune system responds to the ‘invading’ germs. The body creates anti-bodies to the bacteria or virus which protect the person against that infection in the future. For vaccines to be effective they must be given before exposure to the virus or bacteria.

There are vaccines for some sexually transmitted infections, including hepatitis A, hepatitis B, and HPV.


In British Columbia, the hepatitis A vaccine is free for:

  • Men who have sex with other men, or are not yet sexually active but are questioning their sexual orientation
  • Individuals who are living with HIV
  • Inmates of provincial correctional facilities
  • People who use intravenous drugs or share drug equipment
  • Aboriginal people age 6 month to 18 years


In British Columbia, the hepatitis B vaccine is free for:

  • Infants as part of routine immunizations
  • Children in Grade 6
  • People born in 1980 or later
  • Individuals who are living with HIV
  • Inmates of provincial correctional facilities
  • People who use intravenous drugs or share drug equipment
  • People at higher risk of hepatitis B infection 


In British Columbia, the HPV vaccine is provided free to: 

  • Children in Grade 6
  • Those who did not start a vaccine series in Grade 6 are eligible to initiate a series prior to age 19 (for males born in 2006 or later) but not thereafter.
  • People aged 9-26 years who are living with HIV
  • Transgender individuals aged 9-26 years
  • Men 9 to 26 years who self-identify as having sex with other men, or are not yet sexually active but are questioning their sexual orientation, or are street-involved
  • Boys aged 9-18 who are in the care of the Ministry of Children and Family Development
  • Males in youth custody services centres


There are two HPV vaccines available in Canada: Cervarix (HPV2) and Gardasil9 (HPV9). The HPV9 vaccine is approved for use in all genders. The HPV2 vaccine is only approved for use in females.

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