Hematologist
CION Cancer Clinics
Staying safe from infection in the first year after a transplant | CION Cancer Clinics
After a stem cell or bone marrow transplant, infection risk is highest in the first weeks, stays raised to around day 100, and remains higher than normal for most of the first year. It lasts longer after a donor transplant or with GVHD. Normal counts do not mean normal immunity. A fever is always a same-day call. Here is what to expect at each stage and how to lower the risk. At CION Cancer Clinics, our haematology team assesses whether a transplant or CAR-T fits your situation and coordinates care with qualified centres.
BP
Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
On this page
- How high is the infection risk in the first year after a transplant?
- Which infections are most likely at each stage?
- What do the main kinds of infection look like?
- What daily habits lower the risk?
- What do families often believe about infection that is not true?
- What can this page not tell you about your own risk?
- Common questions about infection after a transplant
!
If there is a fever, act now
In the first year after a transplant, a fever, shivering, feeling suddenly confused or very weak, fast breathing or a new cough with breathlessness can be a serious infection. Call your transplant team's emergency number straight away. If you cannot reach them, go to the nearest emergency department or call 108, and tell the staff about the transplant and the medicines being taken. Do not wait to see if it settles, and do not give a fever tablet first.
The short answer
How high is the infection risk in the first year after a transplant?
Infection risk is highest in the first weeks, stays raised for the first three months, and remains higher than normal for most of the first year. After a donor transplant, and especially with graft-versus-host disease (GVHD), it can last longer still.
Why the risk lasts so long
A transplant replaces your immune system rather than repairing it. White cell counts often recover within weeks, but the cells that remember germs and make antibodies take many months to rebuild. The protection from childhood vaccines is usually lost too. So a normal blood count does not mean normal defences.
What makes the risk higher
A donor transplant carries more risk than one using your own cells. Medicines that damp down the immune system to prevent or treat GVHD add to it, as does GVHD itself, steroids, a central line, diabetes, and older age. Your team knows which of these apply to you and plans the preventive medicines and checks around them.
Preventive medicines against viruses, fungi and some pneumonias are a normal part of the first year. Never stop one because you feel well.Not sure whether this applies to you?
Ask an oncologistHow the risk changes
Which infections are most likely at each stage?
-
Before the new marrow takes
White cells are almost absent. Bacteria from your own gut, skin and mouth, and fungal infections, are the main worry. The central line is a common entry point. Most people are still in hospital during this stage.
-
From engraftment to around day 100
Counts are back, but immunity is weak and immune-suppressing medicines are at their strongest. Viruses such as CMV can wake up, and fungal and pneumonia risks continue. Regular blood tests look for viruses before they cause illness.
-
From day 100 to the end of the first year
Risk slowly falls. Shingles, chest infections and infections from bacteria that cause pneumonia and meningitis are more typical now, especially if GVHD is active. Vaccinations usually restart in this period on your team's schedule.
-
Beyond the first year
For many people the risk nears normal. For those still on treatment for GVHD it can stay raised, and some precautions continue.
Know the signs
What do the main kinds of infection look like?
Signs can be milder than usual because the immune system is not reacting strongly. Tell the team early.
Bacterial
Fever, chills, a red or painful line site, burning urine, or a cough with coloured phlegm. These can become serious within hours.
Viral
Colds and flu can go to the chest. CMV may cause no symptoms and is found on blood tests. Shingles shows as a painful band of blisters on one side of the body.
Fungal
Mould spores in dust, soil and damp walls can cause chest infections. A persistent fever, cough, chest pain or blocked, painful sinuses need checking.
Common sources at home
- Building or renovation work
- Potted plants and garden soil
Food and water
Loose motions, vomiting or stomach cramps after eating. Food and water safety rules exist to prevent these.
Every day
What daily habits lower the risk?
- Wash hands with soap before eating, after the toilet and after coming in from outside
- Take every preventive medicine exactly as prescribed
- Keep people with a cold, cough, fever or chickenpox away
- Wear a well-fitting mask in hospitals, crowds and while travelling
- Brush teeth gently twice a day with a soft brush
- Stay away from construction dust, gardening and animal litter
- Drink boiled or filtered water and eat freshly cooked food
- Keep a thermometer at home and use it whenever you feel unwell
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Commonly believed
What do families often believe about infection that is not true?
"His counts are normal now, so he can go to the wedding."
Normal counts do not mean the immune system has rebuilt. Crowded functions, temples on festival days and long bus or train journeys are among the easiest places to catch something. Ask the team before any large gathering in the first year.
"A mild fever is just tiredness. Let us wait till morning."
After a transplant, infections can move fast and show few signs early on. A fever is always a reason to call the team the same day, even at night.
"Antibiotics from the local chemist will be enough."
The wrong antibiotic can delay the right treatment and can interact with transplant medicines. Blood tests and cultures are needed first. Let the team decide.
"The old vaccines still protect me."
Most of that protection is lost after a transplant. Vaccines are given again later on a set schedule, and live vaccines need special care.
Being straight with you
What can this page not tell you about your own risk?
This page cannot tell you exactly how long your own risk will last or which precautions you can drop. That depends on the type of transplant, GVHD, your medicines and how your immunity tests look over time. Two people at the same month after transplant can need very different rules.
Ask for your own list
Ask the transplant team for written rules for your case: which symptoms mean a call at night, which medicines must never be missed, which vaccines are due and when, and when you can return to work, school or travel. Keep the list on the fridge where the whole family can see it.
Getting help closer to home
If you have moved back to a Telangana or Andhra Pradesh district, work out now which nearby hospital you will use for an emergency, and carry the discharge summary. CION's haematology team can review reports and help you stay in step with your transplant centre, which remains in charge of your transplant care.
Questions we are asked
Common questions about infection after a transplant
How long do I need to wear a mask after transplant?
Most teams advise a mask in crowds, hospitals and while travelling for much of the first year, and longer if you are on treatment for GVHD. At home with healthy family, it is usually not needed. Your team will tell you when it is safe to relax this.
Can we keep our pet dog or cat?
Often yes, if the pet is healthy, vaccinated and already lives with you. Someone else should clean litter, cages and bird droppings. Avoid bites and scratches, and wash hands after touching animals. Getting a new pet in the first year is usually discouraged.
When can children in the house get their vaccines?
Children should usually keep up with their own vaccines, because that protects you too. A few live vaccines need extra care around someone with a weak immune system. Tell the child's doctor about the transplant and check with your team before any live vaccine.
Is it safe to travel by train or bus back to our village?
Short, planned journeys are often possible, with a mask and clean hands. Long, crowded journeys carry more risk. Ask the team first, carry your medicines and discharge summary, and know which hospital near your destination you would use in an emergency.
What should I do if someone at home falls ill?
Keep them in a separate room if possible, ask them to wear a mask, and do not share towels, utensils or bathrooms where you can avoid it. Wash hands often. If they have chickenpox, shingles or flu, tell your transplant team the same day, because treatment to protect you may be needed.
Why do I keep getting virus blood tests?
Some viruses, such as CMV, can become active without symptoms after a transplant. Regular blood tests find them early, so treatment can start before they cause illness. A positive result does not always mean you are sick, and your team will explain what it means for you.
Can I go back to work or school in the first year?
Many people return during the first year, often part-time and later rather than earlier. Crowded offices, classrooms and commuting add risk. The timing depends on your counts, GVHD and energy. Discuss it with your team and ask whether any extra precautions are needed.
Does a chest infection always mean a hospital stay?
Not always, but it often means urgent tests, and many people are admitted so treatment can go into a vein and be watched closely. Breathlessness, a high fever or feeling faint are reasons to go to the emergency department rather than wait for a clinic slot.
Your Haematologist
Meet CION's haematologist. One specialist for your blood report and your plan.
Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Patient stories
Hear it from people we have treated
Every story is a video, in the patient's own words. Nothing here is a written testimonial.
Sources
- National Cancer Institute — Stem Cell Transplants in Cancer Treatment
- American Cancer Society — Stem Cell or Bone Marrow Transplant
- NHS — Stem cell and bone marrow transplants
- Leukemia & Lymphoma Society — Stem Cell Transplantation
- National Health Mission — National Health Mission
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
CMV Reactivation After TransplantThe virus checked on your blood testsDiet and Food Safety After TransplantPreventing infections from food and waterThe First 100 Days After TransplantThe highest-risk months, stage by stageBlood counts during chemotherapyWhat white cell and platelet numbers meanLife After TransplantEvery guide for the months and years ahead
Talk to us
Worried about infections after a transplant?
Tell us what has happened so far. CION's haematology team will review your reports and help you stay in step with your transplant centre. One helpline serves every CION centre.