Cancer patients who are treated with chemotherapy are more likely to get infections through everyday activities, or from health care settings. One out of every 10 cancer patients who receives chemotherapy gets an infection that requires a hospital visit.
You get an infection when germs enter your body and multiply, causing illness, organ and tissue damage, or disease. Bacteria and viruses cause infections.
The immune system helps your body protect itself from getting an infection. Cancer and chemotherapy can damage this system, reducing your numbers of infection-fighting white blood cells and making it harder for your body to fight infections.
If you get a fever during your chemotherapy treatment, it's a medical emergency. Fever may be the only sign that you have an infection, and an infection during chemotherapy can be life-threatening.
You should take your temperature any time you feel warm, flushed, chilled, or not well. If your temperature is 100.4°F (38°C) or higher for more than one hour, or 101°F (38.3°C) or higher for any length of time, call your doctor right away, even if it happens in the middle of the night. You should also—

Clean hands help prevent infections. Many diseases are spread by not cleaning your hands, which is especially dangerous when you're getting chemotherapy treatment because your body may not be able to fight off infections like it used to. You and anyone who comes around you, including all members of your household, your doctors, and nurses, should clean their hands frequently. Don't be afraid to ask people to clean their hands. Use soap and water to wash your hands. If soap and water aren't available, it's OK to use an alcohol-based hand sanitizer.
Be sure to clean your hands—

During your chemotherapy treatment, your body may not be able to fight off infections like it used to. When your white blood cell counts are low, you must take infection symptoms seriously. Infection during chemotherapy can lead to hospitalization or death. Call your doctor right away if you notice any of the following signs and symptoms of an infection—
Find out from your doctor when your white blood cell count is likely to be the lowest, since this is when you're most at risk for infection. This usually occurs between 7 and 12 days after you finish each chemotherapy dose, and may last up to one week.
Call your doctor right away, even if this happens in the middle of the night. This is considered an emergency. Don't wait until morning. Keep your doctor's phone numbers with you at all times. Make sure you know what number to call during your doctor's office hours, as well as after hours.