Preventing infections

You may be at risk for infection from the cancer or undergoing treatment. Cancer and its treatment can weaken your immune system, which defends your body against disease. Cancers of the blood can weaken immune systems. Chemotherapy, radiation therapy, corticosteroids, and stem cell transplantation can also weaken immune systems. You may also be at risk for infection if you have been to a place where infections are constant or rising or if you have had a blood transfusion. Click on the links below to learn more about infections and how prevent them.

What is an infection?

An infection is defined by three key features:

  1. A host is invaded by an organism,
  2. The organism multiplies inside the host, and
  3. The organism harms the health of the host.

A good example of an infection in people is chicken pox. Chicken pox is caused by a virus, called the varicella-zoster virus. When the virus has multiplied, it causes an itchy skin rash and flu-like symptoms.

Other examples of infections include:

  • Influenza—a virus, which causes the flu,
  • Plasmodium falciparum—a parasite, which causes malaria,
  • Cryptococcus—a fungi, which causes cryptococcus meningitis,
  • Streptococcus—a bacteria, which causes strep throat, and
  • Abnormal proteins called prions, which cause Creutzfeldt-Jacob disease and other infections. Prion diseases are rare.

How to prevent infections

There are a number of strategies to prevent infections, including:

  1. Antimicrobials. Antimicrobials are drugs that kill or impede the growth of organisms that cause infections. Antimicrobials are grouped by which type of organisms they attack. For example, antibiotics are used for infections caused by bacteria. Your doctor may give you an antimicrobial to prevent an infection during cancer treatment.
  2. Vaccines. Vaccines are biological agents that are inserted into the body to prevent a disease. Ideally, people with cancer should get vaccines before starting cancer treatment.
  3. Avoid germs. Ask your doctor for tips on how to avoid getting infected by animals (including pets) and when gardening and traveling.

Safe and unsafe vaccines

Some vaccines may work well to prevent infection in people with cancer. However, other vaccines may fail to trigger the immune system to defend against an infection. Furthermore, some vaccines may be harmful to people with cancer. Below are NCCN recommendations for immunizations. You should not be vaccinated if any of the following statements describe you:

  1. Allergic to vaccines,
  2. White blood cell counts are not normal,
  3. Taking immunosuppressive drugs,
  4. Undergoing chemotherapy, or
  5. Ongoing infection is present.

Safe for all survivors
The following vaccines should be considered and encouraged for all survivors. These vaccines do not contain live organisms.

  • Tdap (tetanus, diphtheria, and pertussis) if not received before with Td boost every 10 years
  • TIV (trivalent inactivated influenza vaccine) once a year

Safe for young survivors
The following vaccines should be considered and encouraged for young survivors. These vaccines do not contain live organisms.

  • HPV (human papillomavirus) vaccine if not received before

Safe for adult survivors
The following vaccines should be considered and encouraged for adults survivors. These vaccines do not contain live organisms.

  • Pneumococcus if you have a health condition that weakens the immune system
  • PCV-13 (pneumococcal conjugate vaccine) given at least 8 weeks before PPSV
  • PPSV-23 (pneumococcal polysaccharide vaccine) once then again after 5 years if first given PPSV-23 before you were 65 years old

For use in special cases
The vaccines listed below should only be used when needed. Examples of when to use include if you may be traveling soon or there’s a local outbreak. Please consult a doctor who’s an expert in infectious diseases or travel medicine before getting these vaccines.

  • Japanese encephalitis
  • Haemophilus influenzae type b
  • Hepatitis A
  • Hepatitis B
  • IPV (inactivated polio vaccine)
  • Meningococcus
    • Quadrivalent MCV4 (meningococcal conjugate vaccine)
    • Quadrivalent MPSV4 (meningococcal polysaccharide vaccine)
  • Rabies virus
  • Typhoid bacterial capsular polysaccharide

Don’t use or use with caution
Live attenuated vaccines can cause serious health problems if your immune system is weakened. If you are a cancer or transplant survivor with a weakened immune system, you should not receive live attenuated vaccines. If you have close contact with these survivors, you also shouldn’t get these vaccines. If given a live attenuated vaccine, avoid close contact with survivors for 2 to 6 weeks. In some cases, these vaccines may be received if cleared by a doctor who’s an expert of vaccines or infectious diseases. Live attenuated vaccines include:

  • LAIV (live, attenuated influenza vaccine),
  • Measles, Mumps, Rubella,
  • Oral polio,
  • Oral typhoid,
  • Rotavirus,
  • Yellow fever, and
  • Zoster.