Immune System Recovery After Chemotherapy

Chemotherapy, commonly known as chemo is a type of cancer treatment which uses powerful anti-cancer drugs to kill the growing cancer cells. Chemo is administered to patients with the goal of curing them, managing their symptoms and increasing their life span. Since the cancer cells are fast-growing and hard to destroy, anti-cancer drugs are made up of very strong, toxic,  chemicals so they can completely get rid of the cancer cells. Although chemo is very effective against cancer cells it, unfortunately, tends to destroy healthy cells in the body and also causes many undesirable side effects. One of the biggest side effects is the weakening of the immune system, which makes cancer patients vulnerable to various diseases and infections. 

This article focuses on ways in which chemo affects the immune system, how can one help the immune system recover and additional ways to improve your immunity after chemo. 

How chemo affects the immune system

Chemo destroys cancer cells beyond repair, effectively killing them, but healthy cells also get damaged during the process as chemo can not differentiate normal cells from fast-dividing cancer cells. Because of this, there is certainly extensive damage to the healthy cells produced by the bone marrow. Bone marrow is responsible for producing red blood cells, white blood cells (immune cells) and platelets. The white blood cells consist of different types of cells such as neutrophils, monocytes and lymphocytes (B cells and T cells) which play an important role in our immune system. These white blood cells are responsible for protecting our body from various bacterial and viral diseases, and infections. Chemo affects white blood cells more than other types of cells making the cancer patient’s immune system weak and prone to various infections.1,2 

Our bodies have mechanisms to repair and restore the immune system, but studies done among breast cancer patients showed it took more than 9 months for the restoration of the B and T immune cells destroyed during chemo.3,4  The study also found the depletion of immune cells started within 2 weeks of chemo administration. This makes the patients very vulnerable to multiple infections while chemo is administered. Chemo can last from 2-6 months depending on the type of cancer one is diagnosed with. During this time, the patient is considered to be immunocompromised, and extra precautions are taken to protect them from infections.

Another commonly associated effect of chemo on the immune system is neutropenia. Neutropenia is the decrease of neutrophils (a type of white blood cell), which are responsible for protecting the body from infections.

While chemo is known to cause depletion of one’s immunity the amount of depletion usually depends on factors such as:2,5

  • The type of anti-cancer drug used. There are instances when the oncologist may prescribe a combination of two or more drugs which can affect the immune system more
  • The amount (dose) of anti-cancer drug administered during each treatment
  • The number of times the treatment is repeated (cycles of chemo)
  • The type of cancer and whether it has spread. Cancer with a solid tumour such as breast cancer or prostate cancer will be treated differently than blood cancers 
  • Other factors such as patient age, nutritional and overall physical health are also seen to play a role in the recovery of the immune system 

Some anti-cancer drugs tend to have a stronger effect on the immune system than others. It is advised to talk with your doctor about the side effects of the drugs if chemotherapy is prescribed for you.   

To understand more about how cancer affects the immune system read the article “The immune mmune system and cancer” here.

Recovery guide for the immune system after chemo

The immune system tends to start recovering on its own a few weeks after stopping chemo treatment. During this time, your immune system begins restoring its functions. You can take certain measures to help speed the process as well as protect yourself from any infection. 

Some of the steps you can follow to aid your immune system recovery:2,4 

Maintain a healthy diet: chemo tends to deplete nutrients in your body, hence it's important to supplement it through food. Aim to include vitamin and protein-rich foods such as fruits, vegetables, eggs and lean meat. The loss of appetite is a side-effect of chemo, so ensure to get a dietician to work with you to develop a meal plan to increase your appetite slowly while maintaining your daily nutritional intake.   

Get plenty of rest: chemo is very stressful for the body and getting enough rest during sleep is very important for immune system recovery. Aim to get 7-10 hours of sleep every night. Cancer symptoms and chemo side effects might keep you up at night at times. Talk with your doctor to manage your symptoms and ask if certain medications can improve your quality of sleep.

Keep your stress under check: chemo is not only stressful for your body it also unfortunately affects your mental health. Increased stress during this period could cause chemical and hormonal fluctuations in your body, which in turn makes your immune system weak. From the time of cancer diagnosis to undergoing chemo is a very emotional time. Remember you are not alone, talk with your family, reach out to cancer support groups and seek counselling to maintain your mental health.

Avoided crowded places: Being in a public area/crowds will expose you to many infections. Try to avoid being in such places but if you need to go outside wear a mask to protect yourself, use hand sanitiser and avoid touching people or surfaces. Limit your contact with people even if they only have flu or the common cold, as it can cause severe infections because you are immunocompromised.  

Practice better personal hygiene: It goes without saying that it is very important to wash your hands when using public spaces, washrooms and even in your own house. Ensure to take regular warm showers and gently clean the area through which chemotherapy is administered. Avoid the disposal of animal waste or compost to protect yourself from germs. Try to have a separate clean place in your house for you to rest and sleep. Maintaining these practices will greatly decrease your chance of getting an infection.   

Ask for medication to boost immunity: Ask your doctor if preventive medication to avoid infections is required for you. If your doctor finds out you have significantly fewer immune cells than normal, they may prescribe antibacterial, antifungal or antiviral medications. There are also drugs with boost the growth of immune cells and are administered to patients if they are found to be severely immunocompromised.  

It is also very important to keep a track of your existing symptoms. Any new symptoms such as cough, chills, fever or nasal discharge might be due to an infection. Contact your doctor if you experience any new symptoms so they can guide you about the next steps for treating it and also give you preventive medication.  

Other things to consider for immune system recovery

The immune system is sensitive, hence it is very important to maintain your physical, mental and emotional health during its recovery. Along with taking the required medications, it is also very important to design a lifestyle that will ensure immune system recovery during and after the end of chemo. 

Some other factors to keep in mind for immune system recovery:4,6 

Keep up with your vaccinations: Make sure to get your COVID-19 vaccine along with its boosters. Talk with your doctor to get an additional dose for patients with weakened immune systems. Also, take your flu jabs regularly.    

Try to get light exercise: Tiredness is associated with chemo. Once you feel like you have rested well, try to incorporate walks and stretches every day. These small movements can improve your circulation as well as boost your mood.  

Don't smoke and avoid alcohol: Smoking is a deadly combination for cancer and even deadlier for a patient recovering from chemo. Get help to completely cut smoking from your life and also avoid accidental inhalation of smoke. Alcohol consumption is not allowed during chemo as it interferes with the anti-cancer drugs and the same goes for the recovery period as it can slow down the immune system recovery. 

During chemo, your doctor ensures to regularly check your white blood cell count and prescribe any medication accordingly. In most cases, antibiotics are given along with chemo as a preventive measure.  


Chemo affects your immune system as it can't distinguish between immune cells and cancer cells. Hence a lot of immune and other healthy cells get damaged during chemo. The immune system recovery takes about a few months after the treatment is stopped. Fortunately, there are ways and medications to protect yourself from any infections while your immune system is healing. Make sure you do not ignore any minor symptoms during this time period because they could be due to an infection and must be immediately looked after by a doctor. This is an emotionally hard time, be kind to your body and remember there is your family and other support groups you can rely on.


Does chemo shorten your lifespan?

Over the years chemo increased the survival rate of cancer patients. There was a remarkable increase in the lifespan of children and adults treated with chemo. Despite advancements, survivors still run the danger of living shorter lives, particularly if radiotherapy was combined with their treatment.7 With the development of safer anti-cancer drugs, chemo is seen to increase life expectancy rather than decrease it.  

Does chemo affect the immune system permanently?

No, chemo temporarily weakens your immune system as immune cells are damaged during the treatment. After the end of chemo, the recovery of the immune system begins and a complete recovery can be seen from was early as approximately 21-28 days or even 9 months depending on the type and duration of chemo you underwent.2,4


  1. Parkin J, Cohen B. An overview of the immune system. The Lancet. 2001 Jun 2;357(9270):1777-89.  Available from:
  2. How chemotherapy affects the immune system. Available from: 
  3. Verma R, Foster RE, Horgan K, Mounsey K, Nixon H, Smalle N, Hughes TA, Carter CR. Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer. Breast Cancer Research. 2016 Dec;18(1):1-2.  Available from:
  4. After chemotherapy, immune system recovery may be slower than believed. Fred Hutch. 2016. Available from: 
  5. Why people with cancer are more likely to get infections. Available from: 
  6. How to boost your immune system. Harvard Health. 2014. Available from: 
  7. ESMO. Life expectancy of adult survivors of childhood and adolescent cancer. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Jeffy Joseph Vinohar

MSc. Oncology, University of Nottingham, England

Jeffy is an aspiring academic scientist with a bachelors in Biomedical sciences, Biotechnology with a keen interest in cancer studies. During her masters she aimed to learn more about making healthcare accessible and solutions to reduce healthcare inequalities in the field of oncology.
She currently interested in paediatric neuro-oncology and developing less invasive therapeutics for it by obtaining a PhD in coming years, while being involved with simplifying scientific research into health awareness articles.

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