Managing your health: a guide for people living with HIV


12. HIV-related infections and cancers

This chapter discusses some of the infections and cancers that can develop in people living with HIV. With early diagnosis, proper monitoring and care, most of these illnesses can be prevented.  They are much less frequent than they were before effective anti-HIV drugs became available. However, it’s important to know about these infections and cancers so that you can take the proper steps to prevent them.

Life-threatening infections called opportunistic infections occur with untreated HIV, which weakens your immune system to the point that your body becomes vulnerable to infections that would not affect you otherwise.

There are a number of infections and illnesses that can develop in people who are living with HIV, particularly those people who are not able to take anti-HIV drugs. Some of these life-threatening infections are called opportunistic infections. These only occur if your immune system is quite weakened (usually in the absence of anti-HIV drug therapy) and your body becomes vulnerable to infections that would not affect you otherwise.

Co-infections are illnesses that can occur in people with normal immune systems, but they can impact how you live with HIV.

Some types of cancers are thought to be more common in people with HIV.

Increasingly, the distinction between these different types of infections—life-threatening infections, co-infections and even some cancers—is blurred, as some infections can fit all three categories (for example, human papillomavirus is a co-infection which can lead to cervical and anal cancer).

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Life-threatening infections

If your CD4+ cell count gets lower, your immune system becomes unable to fight off a number of common viruses, bacteria and parasites.

These infections occur only when a person’s immune system has been seriously weakened by HIV due to lack of diagnosis and/or anti-HIV treatment. As described in Chapter 2, HIV… the basics, HIV attacks immune cells called CD4+ cells, which are needed for fighting off infections and some cancers. A normal CD4+ cell count in an HIV-negative person is around 500 to 1,500 cells in each cubic millimetre (mm3) of blood. If your CD4+ cell count gets lower, your immune system becomes unable to fight off a number of common viruses, bacteria and parasites. These infections can then take hold. (They are sometimes called opportunistic infections because they take advantage of your weakened immune system.)

Life-threatening infections are uncommon now, since most people take anti-HIV drugs, which controls their viral load, raises their CD4+ levels and stabilizes and restores immune system function. This helps prevent life-threatening infections caused by HIV.

The main danger nowadays is in not finding out you are HIV-positive until your CD4+ cell counts are already so low that you are at risk, or are already sick with a life-threatening infection.

The more common life-threatening infections are listed in the accompanying table. Some of these can still occur in people with relatively high CD4+ levels, but are more serious when the immune system is weakened.

Life-threatening infections include a lung infection called Pneumocystis pneumonia (PCP), an eye infection caused by cytomegalovirus (CMV), a brain infection called toxoplasmosis, and a generalized infection called Mycobacterium avium complex (MAC). If it happens that you find out you have HIV when your CD4+ cell count is very low, there are drugs you can take to prevent these infections. This is called prophylaxis.

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HIV-related infections: These are some of the more common life-threatening infections that can affect people whose immune systems are severely weakened by HIV.






What is it?

A lung infection that causes pneumonia. Can sometimes infect other organs.

An infection that can infect the brain, but also the eye or other organs.

A viral infection of the eye. Can also affect other organs.

An infection of the gastrointestinal (GI) system that can also affect other organs.

What is it caused by?

Pneumocystis jirovecii (formerly called Pneumocystis carinii)

Toxoplasma gondii


Mycobacterium avium

You’re most at risk with CD4+ cells counts …

Under 200 cells/mm3

Under 100 cells/mm3

Under 50 cells/mm3

Under 50 cells/mm3

Symptoms to watch for include1

Shortness of breath, trouble breathing, tiredness, dry cough, fever.

Constant headache, fever, seizures, or stroke-like symptoms (loss of vision, sudden weakness or speech difficulties).

Any sudden or unusual changes in vision.

Severe diarrhea, fever.

Can cause…

Pneumonia (inflammation of the lungs). Can be fatal if not treated.

Damage to the brain, eyes, or other organs.

Permanent blindness.

Disseminated (body-wide) disease. Can be fatal if not treated.

Can be prevented by2 

Taking preventive medication (usually Septra/ Bactrim) if your CD4+ cell counts are under 200 cells/mm3.

Taking food safety precautions, avoiding contact with infected cat feces, taking preventive medication (usually Septra, as for PCP) if your CD4+ cell counts are under 100 cells/mm3.

Watching carefully for symptoms if CD4+ cell counts are below 50 cells/mm3, and treating immediately if necessary.

Taking preventive medication (azithromycin or other drugs) if your CD4+ cell counts are under 50 cells/mm3.

Is treated with …

Higher doses of Septra/Bactrim, or other drugs.         

The antibiotics pyrimethamine and sulfadiazine or other drugs.

Ganciclovir or other drugs.

Powerful combinations of antibiotic drugs.

  1. These lists of symptoms are not complete. Alert your doctor of any sudden or worrisome symptoms, especially if your CD4+ cell counts are low.
  2. Most life-threatening infections are much easier to prevent than to treat. The best way to prevent life-threatening infections is HIV diagnosis and treatment. Prophylactic (preventive) drugs can lower the risk of many life-threatening infections.

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Co-infections can complicate your HIV treatment and make living with HIV more difficult.

These are infections that can occur even in people with HIV who have adequate CD4+ levels—just as they can occur in people who do not have HIV. They are called co-infections because you have them along with HIV. Co-infections can complicate your HIV treatment and make living with HIV more difficult. HIV can also complicate the treatment and diagnosis of a co-infection. Although they may occur at normal CD4+ levels, the lower your CD4+ cell count is, the more of a problem they can be.

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Co-infections: These are some of the more common co-infections that people with HIV may have.


Hepatitis B

Hepatitis C


What it is:

A viral infection of the liver.

A viral infection of the liver.

A lung infection.

It’s caused by …

The hepatitis B virus (HBV).

The hepatitis C virus (HCV).

A bacterium called Mycobacterium tuberculosis.

It’s transmitted …

Through blood and body fluids; can be transmitted sexually.

Mostly through blood; sometimes through sex, especially in gay men.

By close contact with someone with TB, by breathing the air they have coughed or sneezed into.

How do I know I have it?

HBV may cause flu-like symptoms or jaundice, but there may be no symptoms. Blood tests can tell whether you’ve been exposed.

There are often no symptoms of being infected with HCV. Blood tests can easily detect it.

A skin test can tell whether you have been exposed.

Can cause …

Liver damage. However, many people with HBV clear the infection on their own. Blood tests can tell whether you are actively infected.

Liver damage and, in the long term, liver cancer.

Fever, chills, trouble breathing, and weight loss. TB can cause serious or fatal illness if not detected and treated.

Can be prevented by …

Vaccination; avoiding exposure to the HBV virus.

Avoiding exposure to the HCV virus.

Avoiding exposure.

It’s treated by …

Antiviral drugs, but it’s not clear which treatment is best. People with HIV and HBV must be treated carefully to avoid drug resistance.

A combination of antiviral drugs. Treatment lasts a few months, has few side effects and cures most people.

A several-month course of drugs, depending on whether the infection is “active” or not. TB can easily become drug-resistant if the full course of treatment isn’t taken.


Chronic hepatitis is a common co-infection for many people with HIV.

Chronic hepatitis is an increasingly common co-infection for many people with HIV. Hepatitis is a liver condition usually caused by viruses called hepatitis A, hepatitis B or hepatitis C. These viruses infect the liver and can cause jaundice (yellow skin and eyes), dark urine, pale stool and severe fatigue. It is a good idea for your doctor to check regularly for these infections. Hepatitis B and C are transmitted by:

  • blood-to-blood contact through sharing drug-using equipment, or personal care items like razors;
  • transfusion of blood and blood products before 1992 when the Canadian system started screening;
  • unprotected sexual intercourse;
  • being passed from mother to child during childbirth.

Hepatitis A is another, usually less serious, viral infection of the liver. Hepatitis A is spread through feces (shit), and you can be infected by contaminated food (for instance, if someone handling your food has hepatitis A and did not wash his or her hands). If you are exposed to hepatitis A, it can make you quite sick for a few weeks, but your immune system usually clears it. Hepatitis A very rarely causes permanent damage unless you already have hepatitis B or C as well.

If infected with the hepatitis A or B virus, some people get over the initial liver infection and develop immunity. This is much less likely to happen in people with HIV who are co-infected with hepatitis C. Without treatment, people can develop chronic hepatitis, remain infectious to others and develop ongoing liver problems.

As described below, there are vaccinations that will prevent you from getting hepatitis A and B infection. There is no vaccination available for hepatitis C.

Effective antiviral treatments are available for both hepatitis B and C infection. Treatment can cure hepatitis C and keep hepatitis B under control. There are interactions between drugs to treat hepatitis and HIV, so make sure you see a doctor with expertise in both conditions.

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Tuberculosis (TB)

TB is a concern for people with HIV because it is so easily spread. TB is spread through the air when someone with TB coughs or sneezes.

TB is a concern for people with HIV because it is so easily spread, especially in places where people live close to each other, in poverty and without adequate medical care.

TB usually infects the lungs, but it can also affect the bones, brain and other organs in your body. TB is spread through the air when someone with active TB coughs or sneezes. Diagnosis of TB is done by skin tests, tests of your sputum (phlegm) and chest X-rays. There are effective treatments for TB, but they need to be taken every day for many months. Missing doses, or stopping before the full treatment period is over, can cause the TB infection to become drug-resistant and much more difficult to treat. People with HIV with a history of previously treated TB may have it reactivate (come back again) if their immune system weakens.

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Herpes infections

Herpes is a family of viruses that includes:

  • Herpes simplex, which causes cold sores on the mouth or painful sores on the genitals.
  • Varicella-zoster, which initially causes chicken pox and when reactivated causes painful sores called shingles anywhere on the skin.
Usually, the immune system keeps herpes infection under control until something like stress or a high fever brings the sores out in an outbreak.

Herpes infections are common and are often transmitted by physical contact and sex. Usually, the immune system keeps herpes infection under control until something like stress or a high fever brings the sores out in an outbreak lasting seven to 10 days, or longer. The lower your CD4+ cell count, the more frequent outbreaks may be. They may also last longer.

People with HIV with extremely weak immune systems (CD4+ cell counts less than 100 cells/mm3) are at risk for herpes infections all over the body (disseminated herpes) or in the brain (herpes encephalitis). People with frequent herpes outbreaks (even with normal CD4+ levels), or people at risk for more serious herpes infections, can take antiviral drugs—usually valacyclovir or similar drugs—to keep the herpes virus suppressed.

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Fungal infections

Fungal or yeast infections can happen whether you are HIV-positive or not. Women get vaginal yeast infections, and men and women can get athlete’s foot or fungal infections on the skin or nails. The more weakened your immune system is, the more this can be a problem.

Even people with moderate CD4+ cell counts can get a fungal infection in the mouth or vagina called candidiasis or thrush. Antifungal creams, pills and vaginal suppositories are available to treat these problems, and probiotic supplements or yoghurts with friendly bacteria may also help. Watch your diet because the more sugar you eat, the more susceptible you are to fungus, which loves sugar.

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Sexually transmitted infections

Some of the infections discussed above can be passed on in many ways, including through sex. Some other infections, like chlamydiagonorrhea and syphilis, and the virus HPV, are virtually always transmitted sexually. For more information about sexually transmitted infections, see Chapter 7 (Your sexual health).

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Other infections

Common infections can activate your immune system and increase the chance of HIV replication. There are actions you can take to prevent infections. Many of these are common-sense practices like washing your hands often and well, getting plenty of rest and avoiding other people who have colds or the flu. Some other things to consider are discussed below.

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Your water supply

Most city water supplies are tested and purified to ensure they are free of infectious organisms (germs). If you get your water from a well or an untreated water source, you should have it tested for impurities and/or drink only boiled or bottled water. Water-borne infections like CryptosporidiumE. coli and Giardia cause diarrhea and severe illness, and people with HIV are vulnerable. You should take precautions when travelling to parts of the world where outbreaks of cholera, CryptosporidiumE. coli and hepatitis A can be passed on through water.

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The food you eat

Avoiding contaminated food is also an important way of preventing infections, such as E. coliSalmonella and Listeria. You can avoid many infections—both mild and potentially serious—by:

  • making sure that your hands and the surfaces that you are preparing the food on are clean;
  • ensuring that meat and seafood is thoroughly cooked;
  • carefully peeling or washing fruits and vegetables;
  • avoiding foods that are past their “best before” dates or are spoiled;
  • keeping raw meat, poultry and seafood separate from ready-to-eat foods such as fruits or salads and keeping raw meat, poultry and seafood separate from cooked foods. This includes paying attention that you don’t reuse your cutting board for ready-to-eat foods after it has been used for raw meat or seafood;
  • not letting food sit out at room temperature for long if it is prone to spoiling. Keep hot things hot and cold things cold;
  • paying attention to warnings about food contamination.

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Your pets

Pets are very important to some people with HIV and offer many benefits; however, some people with HIV are vulnerable to infections from pets. There is no reason you should have to avoid having a pet if you are HIV-positive. But do take care when handling pets and their waste. For example, when changing your cat’s litter you should wear gloves and avoid breathing in the dust, which can transmit toxoplasmosis. Also, always wash your hands after handling any animal’s waste.

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Your doctor should ensure you have had all your childhood vaccinations for infections such as measles and mumps, and keep you up to date with vaccinations for tetanus and pneumococcal pneumonia.

Vaccines stimulate your immune system to develop resistance to an infection, without causing illness themselves. Your doctor should ensure you have had all your childhood vaccinations for infections such as measles and mumps, and keep you up to date with vaccinations for tetanus and pneumococcal pneumonia.

People with HIV should consider vaccination for hepatitis A and B, which involves two or three injections over a six-month period. Unfortunately, there is no vaccination available for hepatitis C.

Most doctors recommend that people with HIV get the flu vaccine every year in autumn for prevention of the influenza virus. There is an oral vaccination available for cholera and E. coli that will prevent traveller’s diarrhea, and this should be considered for anyone travelling to developing parts of the world. HPV vaccination is also available.

Some people with HIV, particularly those with weak immune systems, do not get the full effect from a vaccination, and may need higher vaccine doses or booster shots. The vaccine for measles, mumps and rubella should be avoided if your CD4+ cell count is too low. Other live vaccines, like varicella, oral typhoid, oral polio and BCG for TB, should be avoided by all people with HIV because they are made from live virus and may cause serious illness in people with HIV.

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Vaccine recommendations: Vaccine recommendations are based on the protective benefit of the vaccine, versus any possible risk to people with weakened immune systems. You should discuss vaccinations carefully with your doctor (like all medical procedures); these are some of the general guidelines for people with HIV:



Given as

Measles, mumps & rubella

Should be given in childhood. Probably safe for HIV-positive adults except those with very low CD4+ cell counts.

A single injection at around age 1, with a booster at age 4 to 5.

Pneumococcal pneumonia

Should be given at least once for all people with HIV. Consider revaccinating after five years.

A single injection (Pneumovax).

Hepatitis A and B

Should be considered.

Two or three injections over a six-month period.


Has not been evaluated in HIV-positive women or in men of any HIV status.

A series of injections, preferably in teenage girls before they become sexually active.


Recommended annually for all people with HIV.

One shot every year, in the fall.

Oral: typhoid, polio

Injectable: varicella, BCG vaccine for TB, smallpox, cholera

These and other live vaccines should generally be avoided by people with HIV. Some may be appropriate in those with higher CD4+ cell counts.

Not generally given to people with HIV.

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With a weakened immune system, people with HIV can become more vulnerable to certain types of cancer. Cancers seem to be more common in people with HIV even when their immune system is relatively healthy.

Cancer is the abnormal and uncontrolled growth of cells in different parts of the body. These cancerous growths then destroy healthy cells and cause serious illness. A normally functioning immune system acts to suppress this abnormal growth of cells.

People with HIV can become more vulnerable to certain types of cancer. Some of these cancers occur only when the immune system is weakened. Other cancers seem to be more common in people with HIV even when their immune system is relatively healthy.

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Kaposi’s sarcoma

Kaposi’s sarcoma (KS), a rare form of skin cancer, is caused by a member of the herpes virus family and can be life-threatening.  It causes purple lesions on the skin that looked like bruises. Although slow growing, if it spreads to internal organs it could lead to illness and death. In the early days of HIV, it was quite common in people living with HIV. When HAART was introduced, KS became uncommon and now only occurs in people with very weak immune systems.

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Non-Hodgkin’s lymphoma

When the cells in the lymph nodes become cancerous, this is called lymphoma. The non-Hodgkin’s type of lymphoma (NHL) is more common in people with HIV. The symptoms of NHL may include persistently swollen lymph glands, fevers, chills and sweats and weight loss. In the case of central nervous system lymphoma, the symptoms are often headaches and seizures.

Diagnosis of lymphoma, like many cancers, is done by biopsy where a sample of tissue from a swollen lymph node is examined under the microscope for evidence of abnormal cells. In the event of central nervous system lymphoma, the diagnosis is made by examining cerebrospinal fluid tapped from the spine. Lymphoma is usually treated by chemotherapy, where powerful anti-cancer drugs are injected into the vein on a regular basis, and/or radiation therapy where high-powered X-rays are directed at the cancer cells.

If you notice persistently swollen lymph glands (or nodes) anywhere in your body, you should alert your doctor.

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Cervical cancer

The cervix is the opening of the uterus (womb) inside a woman’s vagina. Sometimes abnormal cells can start to grow on the cervix, usually as a result of HPV infection. Over time, these abnormal growths can become a pre-cancerous condition called cervical dysplasia. If dysplasia is not found and treated, it can become cancer.

All women should have annual Pap tests to look for dysplasia.

To prevent this, all women should have annual Pap tests to look for dysplasia from a small scraping of cells from the cervix. Women with a history of genital warts or cigarette smoking should have Pap exams more frequently. If dysplasia is found, it is usually treated with a laser in a procedure called colposcopy.

The HPV vaccine will protect women from some, but not all, strains of HPV and so it is hoped it will prevent some cases of cervical cancer. However, this vaccine is effective only if it is given before women have been exposed to the HPV strains the vaccine targets.

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Anal cancer

Cancer in the anal canal of men and women is similar to cervical cancer. It is also usually caused by infection with HPV and, like cervical cancer, develops over time from dysplasia to cancer. Risk factors include a history of anal sex and/or genital warts. Both men and women with HIV are thought to be more vulnerable to this form of cancer. Anal Pap tests are not routinely available throughout Canada, but ask your doctor if testing is available in your area.

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Other cancers

There are many other forms of cancers that people with HIV are thought to be at slightly higher risk for, even without immune suppression. These include Hodgkin’s lymphoma, lung cancer, skin cancer, vaginal cancer in women and testicular and prostate cancer in men. Fortunately, these cancers are not common and can often be successfully treated if they do occur in people with HIV who maintain healthy immune systems with effective anti-HIV drugs.

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Hepatitis C information on Comprehensive information about the prevention and treatment of hepatitis C 

Living with HIV and Hepatitis C Co-infection – Information for those living with both viruses on staying healthy, treatment and protecting yourself and others

Fact Sheets on co-infections, cancers and other conditions - Comprehensive information for people living with HIV and their care providers

Treatment Update and CATIE News – News bulletins about cutting-edge developments in HIV research and treatment

Canadian Food Inspection Agency – This federal government agency, responsible for food safety in Canada, posts up-to-date information on contaminated food products

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About the author

Evan CollinsEvan Collins is a doctor, psychiatrist, researcher, consultant, advocate and person living with HIV. His involvement with HIV/AIDS dates back to 1984 when he joined the board of the AIDS Committee of Toronto. Over the years, he has served on numerous boards and committees, including the CATIE board of directors, and was community co-chair for AIDS 2006. He works as a doctor at Hassle Free Clinic in Toronto, as a psychiatrist in a community mental health program, and as a policy and organizational development consultant. He currently is president of the Ontario HIV Treatment Network and is North American NGO delegate for the Board of UNAIDS.

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