After chemotherapy, your body’s defenses against infection are lower, but there is a lot you can do to stay safer. By paying close attention to hygiene, food safety, crowds and sick contacts, and by calling your care team quickly if you develop a fever or feel unwell, you can greatly reduce your risk of serious infections and protect your recovery.
Understanding Why Chemotherapy Increases Infection Risk
Chemotherapy drugs are designed to kill fast-growing cancer cells. But they can also affect other fast-growing cells in your body, including the cells in your bone marrow that make white blood cells. White blood cells are a key part of your immune system and help you fight infections.
When your white blood cell count drops (especially a type called neutrophils), you are more likely to get an infection from germs that normally would not make you sick. This condition is called neutropenia. During periods of neutropenia, even a minor infection can quickly become serious and lead to a life-threatening condition called sepsis if not treated promptly.
What This Means for You
- You may have fewer signs of infection than someone with a normal immune system.
- Infections can get worse faster than usual.
- You need to contact your oncology team right away if you develop a fever or feel suddenly unwell.
For more detailed information about neutropenia and infection risk, you can review resources from the National Cancer Institute and American Cancer Society.
Key Ways You Can Reduce Infection Risk During Chemotherapy
While you cannot completely eliminate the risk of infection, you can significantly lower it by building a daily routine focused on prevention.
- Practice strict hand hygiene
- Avoid close contact with sick people and crowded places
- Follow food safety guidelines and avoid high-risk foods
- Watch closely for early signs of infection
- Stay up to date with recommended vaccines
- Use masks or other protective equipment when advised
1. Personal Hygiene: Your First Line of Defense
If you are on chemotherapy, frequent and careful hygiene is one of the most effective ways to prevent infection.
- Wash your hands often with soap and water for at least 20 seconds, especially:
- Before eating or handling food
- After using the bathroom
- After blowing your nose, coughing, or sneezing
- After touching pets, garbage, or public surfaces
- Use an alcohol-based hand sanitizer if soap and water are not available.
- Maintain oral hygiene:
- Brush with a soft toothbrush at least twice daily.
- Ask your oncology team before using floss or mouthwash, as some products can irritate your gums or cause bleeding.
- Shower or bathe regularly and gently pat your skin dry to avoid irritation.
- Keep any central lines, ports, or PICC lines clean and dry, and follow all care instructions given by your nurse.
2. Avoiding Crowds and Sick Contacts
During chemotherapy, especially when your white blood cell counts are low, you are more likely to get infections from others.
- Try to avoid crowded places such as busy malls, public transport at rush hour, or large social gatherings.
- Stay away from people who are sick with colds, flu, COVID-19, stomach bugs, or other infections.
- If someone in your household is ill, they should:
- Use a separate bedroom and bathroom if possible.
- Wear a mask when near you.
- Clean frequently touched surfaces regularly.
- Your doctor may advise you to wear a mask in public spaces or healthcare settings. Follow their guidance about when and what type of mask to use.
3. Food Safety and Diet to Prevent Infection
Because your immune system is weaker, you need to be extra careful about foodborne germs that can cause serious illness.
Ask your team if you should follow a “neutropenic” or low-bacteria diet. In general, you should:
- Avoid raw or undercooked:
- Meat, poultry, or fish (including sushi, sashimi, and raw oysters)
- Eggs (no runny yolks or raw cookie dough)
- Unpasteurized milk, soft cheeses made from unpasteurized milk, and unpasteurized juices
- Thoroughly wash fruits and vegetables under running water; avoid salad bars and buffets where food sits out.
- Refrigerate leftovers quickly and reheat them until steaming hot before eating.
- Avoid foods past their use-by date and items with damaged packaging.
At the same time, try to eat a balanced diet to help your body heal:
- Plenty of fruits and vegetables (well washed and, if advised, cooked)
- Whole grains like brown rice, oats, and whole wheat bread
- Lean proteins such as chicken, fish, eggs (fully cooked), beans, and lentils
- Healthy fats from nuts, seeds, and olive oil (avoiding raw nuts from bulk bins)
For practical food safety guidance, you can visit the U.S. FDA Food Safety for People with Cancer.
4. Monitoring for Signs of Infection
Because infections can become serious quickly during chemotherapy, it is vital for you to know what to watch for and when to call your care team.
Call your oncology team or go to the emergency department immediately if you have:
- Fever of 100.4°F (38°C) or higher once, or 100.0°F (37.8°C) or higher lasting an hour or more
- Chills or shaking
- Shortness of breath or trouble breathing
- Chest pain
- New confusion, extreme weakness, or feeling “very unwell” suddenly
Also report:
- New cough, sore throat, or runny nose
- Pain or burning when you urinate, or needing to urinate frequently
- Redness, swelling, warmth, or pus around a wound, catheter site, or port
- New diarrhea, vomiting, or abdominal pain
Do not wait to see if symptoms improve—during chemotherapy, it is always safer to call early.
5. Vaccinations During Chemotherapy
Vaccines can help protect you from serious infections like flu, pneumonia, and COVID-19, but the timing and type of vaccines matter greatly when you are on chemotherapy.
- Always talk with your oncologist before getting any vaccine.
- In general, inactivated (non-live) vaccines, such as the flu shot or COVID-19 vaccines, may be recommended at certain times in your treatment cycle.
- Live vaccines (such as some shingles or measles vaccines) are often avoided during chemotherapy and may need to be given before or after treatment instead.
- Family members may be advised to stay up to date on their vaccines to create a “cocoon” of protection around you.
For more details, you can review vaccine guidance for people with weakened immunity on the CDC website, and then confirm what applies to you with your oncologist.
Boosting and Supporting Your Immune System During Chemotherapy
While there is no magic supplement that can “fix” the immune system during chemotherapy, there are evidence-based ways your medical team and you together can support your body’s defenses.
Medical Support: Growth Factors (G-CSF)
Depending on your specific chemotherapy regimen and your blood counts, your oncologist may recommend medications called growth factors, such as G-CSF (Granulocyte Colony-Stimulating Factor).
- These are usually given as injections.
- They help your bone marrow make more white blood cells more quickly.
- They can shorten the time your white blood cell count is very low and lower your risk of severe infection.
Ask your doctor:
- Whether you are at high risk for neutropenia
- If a growth factor is recommended for you
- What side effects you should watch for (such as bone pain)
Everyday Strategies to Support Your Immune Health
You cannot fully “boost” the immune system during chemotherapy, but you can help it function as well as possible:
- Balanced nutrition: Aim for regular, small meals if your appetite is low. Ask for a referral to an oncology dietitian if you are losing weight or struggling to eat.
- Hydration: Drink plenty of fluids (water, broths, herbal teas) unless your doctor has given you fluid restrictions.
- Rest and sleep: Prioritize getting enough sleep and short rests during the day if you are fatigued.
- Gentle physical activity: If your doctor says it is safe, light movement (like walking, stretching, or yoga) can help maintain strength and energy.
- Stress management: Anxiety and stress are common. Relaxation techniques, support groups, or counseling can improve your overall well-being.
If you are considering vitamins, herbal supplements, or “immune boosters,” speak with your oncology team first—some can interfere with chemotherapy medicines or increase side effects.
Managing Infections If They Occur
Even with the best precautions, infections can still happen. The goal is to catch them early and treat them quickly.
Recognizing and Treating Infections
If you develop symptoms of infection, your oncology team may ask you to go directly to the clinic or emergency department. They may:
- Check your vital signs and examine you.
- Draw blood tests, including a complete blood count to check your white blood cells.
- Take blood cultures or other samples (urine, sputum) to look for the source of infection.
- Start broad-spectrum antibiotics, often given by IV, even before test results return.
Fast treatment can prevent a mild infection from turning into severe sepsis. You should also keep a list of your current medications and your oncologist’s contact information with you at all times, in case you need emergency care.
For more on managing infection during chemotherapy, you can explore patient resources from the Mayo Clinic.
Long-Term Strategies for Reducing Infection Risk
As you move through chemotherapy and into recovery, continuing healthy habits will help reduce infection risk and support your overall health.
Lifestyle Changes That Help Protect You
- Ongoing hygiene: Keep up with regular handwashing, oral care, and skin care even when you feel better.
- Healthy diet: Continue focusing on nutrient-rich foods—fruits, vegetables, whole grains, and lean proteins—to support recovery and blood cell production.
- Regular physical activity: As your strength returns, gradually increase activity like walking, light strength training, yoga, or swimming (when your doctor says it is safe).
- Avoid tobacco and limit alcohol: Both can weaken your immune system and increase infection and cancer risks.
Follow-Up Care and Monitoring
Your oncology team will schedule regular follow-up visits and blood tests to monitor your blood counts and overall health.
- Keep all your appointments, even if you feel well.
- Ask your team when your infection risk is highest (for example, a specific number of days after each chemotherapy cycle).
- Discuss when it is safe to return to work, school, travel, or more social activities.
- Ask about long-term care for any central lines or ports if they remain in place.
Taking a proactive approach—staying informed, asking questions, and reporting symptoms early—can help you move more safely through chemotherapy and into recovery.
Frequently Asked Questions
How can I reduce the risk of infection after chemotherapy?
To lower your risk of infection after chemotherapy, focus on a few key areas:
- Wash your hands often with soap and water, and use hand sanitizer when needed.
- Avoid large crowds and close contact with anyone who is sick.
- Follow food safety rules: avoid raw or undercooked meats, fish, and eggs, and wash fruits and vegetables well.
- Keep your mouth, skin, and any catheter or port sites clean and dry.
- Monitor yourself closely for signs of infection, especially fever, and contact your care team right away if you notice symptoms.
Your oncology team may also use medications like G-CSF to help raise your white blood cell count and reduce your infection risk.
What should I do if I develop a fever after chemotherapy?
If you develop a fever of 100.4°F (38°C) or higher after chemotherapy, treat it as an emergency:
- Call your oncologist or the 24-hour number you were given immediately.
- If you cannot reach your team quickly, go to the nearest emergency department and tell them you are on chemotherapy and may have neutropenia.
Do not take fever reducers like acetaminophen (Tylenol) or ibuprofen before speaking with your doctor, because they can mask a fever and delay diagnosis.
Is it safe for me to be around others after chemotherapy?
You can usually be around healthy family and friends, but you should:
- Avoid people who are sick or recently exposed to contagious illnesses.
- Limit time in crowded indoor spaces, especially during flu and COVID-19 season.
- Ask visitors to wash their hands when they arrive.
- Follow your doctor’s advice about wearing a mask in public or around others.
If you have questions about specific situations—like returning to work, going to religious services, or attending family events—discuss them with your oncology team so they can advise you based on your current blood counts and treatment plan.
Can I still get vaccinated while undergoing chemotherapy?
Some vaccines are safe and important during chemotherapy, while others should be delayed:
- Inactivated vaccines (like the flu shot or COVID-19 vaccines) are often recommended, but the timing may be adjusted to when your white blood cell counts are higher.
- Live vaccines are usually avoided during chemotherapy and may need to be given before or after treatment.
- Family members may be encouraged to get recommended vaccines to reduce the chance of bringing infections home to you.
Always check with your oncologist before receiving any vaccine, including those given at pharmacies or workplaces.
Are there dietary changes I should make to reduce my risk of infection?
Yes. To reduce your infection risk from food:
- Avoid raw or undercooked meats, fish, eggs, and unpasteurized dairy products.
- Wash fruits and vegetables thoroughly; avoid salad bars and buffets.
- Store food safely and reheat leftovers until steaming hot.
To support your immune system and overall health, try to eat a variety of nutrient-rich foods such as fruits, vegetables, whole grains, and lean proteins. If you are losing weight, have a poor appetite, or are unsure what to eat, ask your doctor to refer you to an oncology dietitian for personalized guidance.
