Why do infections happen after a bone marrow transplant?

After your transplant, your immune system is weak and you are at risk for infection. Even though your white blood cell count might be “normal,” your immune system is still recovering. Therefore, infections might still occur.

Causes of infection

The usual causes of infection after a bone marrow transplant include:

*These are more common after allogeneic bone marrow transplants than autologous BMTs, particularly in patients with graft-versus-host-disease (GvHD).

Detecting infection

One of the easiest and most important ways to detect signs of infection is to take your temperature. You should take and record your temperature twice a day.

Preventing infection

  • Autologous transplant patients should follow these restrictions for six months. As long as you are on maintenance medications (such as rituximab or lenalidomide), follow these restrictions.
  • Allogeneic transplant patients should follow these restrictions while taking immunosuppressive medications and while the central line is in place.

Avoiding environmental exposures

Pay close attention to hygiene

This is necessary to help prevent infection. You may shower or bathe normally, as long as you don’t submerge your central venous catheter under water. Daily cleansing with soap and water is the first line of defense against bacteria on the skin.

To help minimize infection and gum bleeding, daily oral (mouth) care is necessary. You may use a soft, nylon-bristled toothbrush or sponge toothette to care for your teeth and gums. Brush your teeth and gums thoroughly with fluoride toothpaste after each meal. Use a mouth wash or rinse as recommended by your healthcare provider.

Prevent infections transmitted by direct contact

Thorough hand washing is crucial, especially during the first 6 months after your BMT or while taking immunosuppressive medicines. Wash your hands with antimicrobial (antibacterial) soap and warm water.

The use of hygienic hand rubs (hand sanitizer) is recommended when you are outside your home if soap and warm water are not available. (Keep in mind that these hand sanitizers do not prevent transmission of the bacteria responsible for causing C diff. colitis.)

Handwashing is necessary:

  • Before eating.
  • Before and after preparing food.
  • After touching pets or animals.
  • After sneezing, coughing, or blowing your nose.
  • After going outdoors.
  • Before and after any central venous catheter care or intravenous infusions.
  • Before taking oral medicines.
  • After touching soiled linens or clothes.
  • After changing diapers.
  • After using the bathroom.
  • After sexual contact, if hands touch genital or anal area.

Remember to wash your hands even if you wear gloves.

Prevent infections transmitted by direct contact and respiratory transmission

Avoid gardening, mulching, raking, mowing, farming, or direct contact with soil and plants. Direct contact with soil and plants increases your exposure to potential pathogens (substances that can cause disease) including aspergillus and cryptococcus. These pathogens can cause serious fungal infections. If you must do any of these activities (for example, you are a farmer), wear a mask and gloves.

Avoid having anything in your yard that collects water, such as birdbaths or empty buckets. Standing water attracts mosquitoes that can transmit West Nile Virus.

This does not mean you should avoid the outdoors. Walking, biking and many other outdoor activities are not only enjoyable but will promote good health.

Prevent respiratory infections

  • Avoid close contact with people who have respiratory illnesses (cough, cold, etc.). Be especially careful around school-aged children, since they are often exposed to other children who are ill.
  • Avoid crowded areas where you are unable to control the distance between you and others (such as at movie theaters or sporting events). Some might feel "safer" wearing a mask when they are outside the home. This is a personal choice, but you are not required to wear a mask when you go outside your home. If you choose to wear a mask, you should still avoid situations, such as crowds, that might increase your risk of infection.
  • Avoid construction sites, including homes or buildings that are being repaired or remodeled. These dusty environments increase your exposure to molds.
  • Avoid tobacco and marijuana use. The use of these substances, along with exposure to environmental tobacco smoke (second-hand smoke), increases your risk for bacterial, viral, and fungal infections.
  • Avoid wood-burning fireplaces, since the wood contains fungus.
  • Avoid house cleaning that will disturb dust and mold, causing it to move into the air (such as vacuum cleaning, dusting, and scrubbing down showers). Once you have the energy, it is not harmful to iron, wash clothes, dry clothes, and wash dishes.
  • Avoid the use of a room humidifier due to the water-harboring bacteria.

Prevent pet-transmitted infections

It is not necessary to part with your pets. However, it is important to minimize direct contact with animals, especially animals that are ill. Please delegate the care of your pets to other family members or friends.

Avoid contact with reptiles, ducklings, or chicks to prevent infection with salmonella.

If you have a cat, do not place the litter box in kitchens, dining rooms, or other areas where food preparation and eating occur. In addition, have someone else handle the daily litter box cleaning during the first 6 months after transplant and when you are taking immunosuppressive medicines to reduce your chance of getting toxoplasmosis. Please keep your cats inside and do not adopt or handle stray cats.

If you have a dog, do not handle or clean up bowel movements.

If hunting, do not gut animals and avoid prolonged contact with earth matter (for example, wild turkey hunting requires laying on earth surrounded by vegetative matter for cover). If fishing, avoid cleaning the fish.

Small children

If you have small children and are unable to avoid changing soiled diapers, you must wear gloves and a mask. After removing the changing the diaper and removing the gloves, wash your hands with soap and water. When possible have another person change diapers.

Water safety

After your transplant, avoid walking, wading, swimming, or playing in recreational water such as ponds, swimming pools, lakes, whirlpools, and hot tubs.

Avoid drinking well water from private wells or from public wells in small communities because tests for microbial contamination are performed too infrequently. Drinking well water from municipal wells serving highly populated areas is thought to be safe because the water is tested more than two times per day for bacterial contamination.

If you drink tap water, routinely monitor the mass media (radio, television, and newspapers) in your area to immediately implement any boil-water advisory. A boil-water advisory means that all tap water should be boiled for at least one minute before drinking.

You may drink bottled water if it has been processed to remove cryptosporidium by one of three processes: reverse osmosis, distillation, or 1-µm particulate absolute filtration. You can contact the bottler directly to confirm that specific bottled water has undergone one of these processes.

Travel safety

Please do not plan to travel to developing countries without first talking to your transplant doctor. Certain countries can pose significant risks for exposure to substances, such as viruses or microorganisms, that can cause disease or infection.


It is beneficial for family members and household contacts to be vaccinated to limit your exposure to vaccine-preventable diseases (such as tetanus, polio, measles, mumps, rubella, influenza, and pneumococcal.) Discuss influenza vaccines and all vaccines with your BMT team.

Children in the household of an immunocompromised patient should receive the MMR (measles, mumps, and rubella) vaccine. Although MMR is a live vaccine, household transmission does not occur. Varicella (chickenpox) vaccine is also a live vaccine. The American Academy of Pediatrics recommends that the child in the household receive the vaccine.

Varicella (chickenpox) vaccine poses a very small risk of household transmission, usually only if the vaccinated child develops a rash. If the vaccinated child develops a rash, the transplant patient might be placed on acyclovir if he or she is not already taking it. It would be much riskier for the transplant patient if the child got the actual chickenpox virus.

When should I call my doctor?

Watch for early signs of infection. It is very important to notify the Bone & Marrow Transplant Team or your local doctor if any of these signs or symptoms of infection occur:

  • Fever of 100.4°F (38.0°C) (even if you feel well).
  • Shortness of breath.
  • Cough with yellow or green sputum (phlegm) or a dry, persistent cough.
  • Sweats or chills, even if you have a normal temperature.
  • Sore throat, scratchy throat, or pain when swallowing.
  • Sinus drainage, nasal congestion, headaches, or tenderness along the upper cheekbones.
  • Trouble urinating: pain or burning, constant urge, or frequent urination. This might also be a side effect of chemotherapy called hemorrhagic cystitis. When this occurs, there might be blood or blood clots in your urine.
  • Cloudy or foul-smelling urine.
  • Redness, swelling, tenderness, or drainage at the site of your central venous catheter.
  • Diarrhea, with or without cramping.
  • Lesions (sores) or white patches in your mouth or on your tongue.
  • Skin rash.
  • Vaginal discomfort, itching, or unusual discharge.
  • Possible exposure to chickenpox, strep throat, herpes, or mononucleosis.

Last reviewed by a Cleveland Clinic medical professional on 08/08/2019.


  • American Cancer Society. Stem cell transplant (peripheral blood, bone marrow and cord blood transplants). (http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/bonemarrowandperipheralbloodstemcelltransplant/bone-marrow-and-peripheral-blood-stem-cell-transplant-toc) Accessed 8/8/2019.
  • National Heart Lung and Blood Institute. Blood and marrow transplant? (https://www.nhlbi.nih.gov/health-topics/blood-and-bone-marrow-transplant) Accessed 8/8/2019.

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