HIV Basics

The basics on HIV transmission, testing and treatment


What Is HIV?

HIV is a virus that can make you sick.

HIV (or human immunodeficiency virus) weakens your immune system, your body’s built-in defence against disease and illness.

Anyone can be infected with HIV. You can have HIV without knowing it. You may not look or feel sick for years, but you can still pass the virus on to other people.

Without HIV treatment, your immune system can become too weak to fight off serious illnesses. HIV can also damage other parts of your body. Without treatment, you can eventually become sick with life-threatening infections. This is the most serious stage of HIV infection, called AIDS (or acquired immunodeficiency syndrome).

There is no vaccine to prevent HIV but there are things you can do to avoid passing or getting HIV. Read on to learn more!

There Is No Cure for HIV… But There Is Treatment

There is no cure for HIV, but with proper treatment and care, most people with HIV can avoid getting AIDS, stay healthy and live a long life.

HIV drugs have to be taken every day. They cannot get rid of HIV but they can keep it under control. They can also dramatically lower or eliminate the risk of passing HIV.

For more on HIV treatment, see CATIE’s Treatment section.

Who Can Get HIV?

Anyone can get HIV, no matter...

  • your age
  • your sex
  • your race or ethnic origin
  • who you have sex with

How Does HIV Get Passed from One Person to Another?

Only 5 body fluids can contain enough HIV to infect someone:

  1. blood
  2. semen (including pre-cum)
  3. rectal fluid
  4. vaginal fluid
  5. breast milk

HIV can only get passed when one of these fluids from a person with HIV gets into the bloodstream of another person—through broken skin, the opening of the penis or the wet linings of the body, such as the vagina, rectum or foreskin.

HIV cannot pass through healthy, unbroken skin.

The two main ways that HIV can get passed between you and someone else are:

  • through sex
  • by sharing needles or other equipment to inject drugs (including steroids or hormones)

HIV can also be passed:

  • by sharing needles or ink to get a tattoo
  • by sharing needles or jewelry to get a body piercing
  • by sharing acupuncture needles
  • to a fetus or baby during pregnancy, birth or breastfeeding

HIV cannot be passed by:

  • talking, shaking hands, working or eating with someone who has HIV
  • hugs or kisses
  • coughs or sneezes
  • swimming pools
  • toilet seats or water fountains
  • bed sheets or towels
  • forks, spoons, cups or food
  • insects or animals

HIV and Sex

HIV can be passed during sex (this includes vaginal, anal and oral sex and sharing sex toys). But there are things you can do to practice safer sex. You can protect yourself and your partner(s) from HIV by doing the following:

  • Use a latex, polyurethane or nitrile condom correctly every time you have vaginal or anal sex. You can use an external condom (sometimes called a male condom) or an internal condom (sometimes called a female condom). Throw out the condom after each sex act and do not use a condom with more than one partner. This will protect you from HIV as well as other sexually transmitted infections, such as gonorrhea and syphilis. (Use only water-based or silicone-based lubricants with latex condoms. Oil-based lubricants can make them break.)
  • If you are HIV-positive and not already on HIV treatment, talk to your doctor about starting treatment. HIV drugs can not only protect your health but also people who are on successful treatment that keeps the virus suppressed do not pass HIV through sex.
  • If you are HIV-negative and at higher risk for HIV, you might be a candidate for PrEP, or pre-exposure prophylaxis. This involves an HIV-negative person taking certain HIV drugs every day to reduce their risk of getting HIV. Talk to your doctor to find out if PrEP might be right for you.
  • Get tested for STIs regularly. Having an STI increases your risk of getting and passing HIV and other STIs.
  • Avoid sharing sex toys (and if you do, cover each one with a new condom before each use). It is also important to clean your toys between vaginal and anal use.
  • Use a condom or dental dam every time you have oral sex. Oral sex is much less risky than vaginal or anal sex, but it’s not completely safe.
  • Choose forms of sexual stimulation that pose little or no chance of HIV, like masturbation or sensual massage.

People can have HIV or other STIs without knowing it because these infections often do not cause symptoms. Don’t assume that your partner knows if they have HIV or any other STI. The only way to know for sure is to be tested.

For more on safer sex, see CATIE’s Sexual Health and Safer Sex section.

HIV and Pregnancy

Without proper treatment and care, HIV can pass from a woman to her baby:

  • during pregnancy
  • at birth
  • through breastfeeding

Protect your baby.

If you are HIV-positive and pregnant, you can reduce the chances of your child being HIV-positive to less than 1 percent by getting proper HIV treatment and care and not breastfeeding after birth.

Talk to your healthcare provider to find out more.

If you are pregnant or thinking about getting pregnant, get tested for HIV. If you are HIV-positive, with proper treatment you can have a healthy pregnancy and a healthy baby.

For more on HIV and pregnancy, see the HIV and Pregnancy section.

HIV and Drug Use

HIV can be passed by sharing needles and other drug equipment.

Sharing needles and other drug equipment is very risky. It can also spread hepatitis C, a virus that damages the liver. Hepatitis C is passed when the blood from someone who has hepatitis C gets into the bloodstream of another person.

Protect yourself and the people you do drugs with.

If you use drugs, there are things you can do to protect yourself and use drugs in a safer way. This is called harm reduction.

To practise safer drug use…

  • Use a clean new needle and syringe every time you use.
  • Use your own drug equipment (such as pipes, bills, straws, cookers, water, alcohol swabs) every time. Never share equipment, not even with your sex partner.
  • Get new needles and supplies from your local harm reduction program, needle/syringe program or community health centre.
  • Get tested for HIV and hepatitis C. If you know that you have HIV or hepatitis C, you can take steps to protect yourself and others. If you test positive for HIV or hepatitis C, talk to your nurse or doctor about getting treatment.

For more on safer drug use, see the Substance Use and Harm Reduction section.

For more on how HIV is transmitted, visit CATIE’s How Transmission Occurs webpage.

HIV and Blood Products

Since November 1985, all blood products in Canada are checked for HIV. A person’s chance of getting infected from a blood transfusion in Canada is extremely low.

There is no chance of getting HIV from donating blood.

HIV and the Law

If you have HIV, you have a legal duty to tell your sex partner(s) before having any kind of sex that poses a “realistic possibility of transmitting HIV.” People with HIV have been convicted of serious crimes for not telling their sex partners they have HIV.

You DO have a legal duty to disclose your HIV status before having:

  • vaginal or anal sex without a condom (regardless of your viral load); or
  • vaginal or anal sex when your viral load is not undetectable (or not low), even if you use a condom.

You do NOT have a legal duty to disclose your HIV status before having:

  • vaginal sex if your viral load is low (or undetectable) and you use a condom. It is not clear whether this also applies to anal sex.

It is not clear how the law applies to oral sex (with or without a condom).

For more information on HIV and the law, contact the Canadian HIV/AIDS Legal Network ( / 416-595-1666). People there may be able to refer you to a lawyer but cannot provide you with legal advice.

CATIE’s Legal Issues section has more information for you to explore.

Know Your HIV Status

The only way to know if you have HIV is to get tested. If you know you have HIV, you can get the treatment and care you need.

It’s important to know your status and start treatment as soon as possible, as it can help you to stay healthy, to live a long life and to avoid passing HIV on to others.

The HIV test involves having some blood taken from your arm or a couple of drops of blood taken from your finger.

After HIV enters the body, it may take time before the test can detect the virus (this is known as the window period). Different HIV tests have different window periods. Some tests can detect HIV as early as 7 days and all tests give accurate results within three months.

Don’t wait. Speak to a healthcare provider about getting tested for HIV as well as other STIs and hepatitis C.

You can’t tell whether you have been infected with HIV by how you feel.

Some people have flu-like symptoms when they first get infected (fever, sore throat or swollen glands). But some people have no symptoms at all.

You can have HIV and not know it.

If you test positive:

  • There have been huge advances in the treatment of HIV, and with the right treatment and care, you can stay healthy.
  • To protect yourself and your partner(s), practise safer sex and avoid sharing drug equipment.
  • Get connected. Visit to locate an HIV organization near you. You can also call or email CATIE for information on HIV services in your area.

For more information if you are newly diagnosed with HIV, see:

HIV Statistics

For statistics about HIV in Canada, check out these CATIE fact sheets:

Or visit the Epidemiology webpage.

Contact Information

For more on HIV, contact: