Why do infections happen after a bone marrow transplant?

After your bone marrow 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:

  • Month 1: bacteria, fungi, herpes simplex virus.
  • Month 2: cytomegalovirus (CMV), other viruses, bacteria, and fungi.*
  • Month 3: varicella zoster virus, bacteria, fungi.*
  • 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.

These restrictions are important for autologous patients for the first month after transplant to prevent infections. These restrictions are important to prevent infections while allogeneic patients are taking immunosuppressive medicines and while you still have central lines.

Allogeneic patients should continue to take their temperature twice a day until all of their immunosuppressive medicines have been discontinued by their health care provider.

Preventing infection

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. After you are discharged from the hospital, 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 gastrointestinal bacterial infections, such as C diff.)

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.

Prevent infections transmitted by direct contact and respiratory transmission

Avoid gardening, mulching, raking, mowing, farming, or direct contact with soil and plants. Creating plant or soil aerosols increases exposure to potential pathogens (substances that can cause disease) including aspergillus and cryptococcus.

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 aerosolize (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.

It is recommended to avoid contact with reptiles, ducklings, or chicks to prevent 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 risk of acquiring toxoplasmosis. Please keep your cats inside and do not adopt or handle stray cats.

Water safety

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

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 > 2 times/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 1 minute before drinking.

You may consume bottled water if it has been processed to remove cryptosporidium by 1 of 3 processes: reverse osmosis, distillation, or 1-µm particulate absolute filtration. You can contact the bottler directly to confirm that a specific bottled water has undergone one of these processes.

Please do not plan to travel to developing countries without first talking to your bone marrow 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 minimize exposure to vaccine-preventable diseases (such as tetanus, polio, measles, mumps, rubella, influenza, and pneumococcal.) Recommendations for a possible revaccination schedule can be provided to you and is needed only for allogeneic transplant patients.

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. The varicella (chicken pox) vaccine is also a live vaccine. The American Academy of Pediatrics recommends that the child in the household receive the vaccine.

The 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.

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