Q: Can Influenza A cause white blood cell counts to drop to 1300?
- Myeongchan Kim
- 3 days ago
- 2 min read
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My child has had a fever for 7 days now. On the third day, a flu test was negative, but today we did an X-ray, blood test, and respiratory panel, and it came back positive for Influenza A. Since the fever has persisted for a week, my child received IV flu medication.
Normally, my child's white blood cell (WBC) count is in the low-normal range of 4,000 to 5,000. It usually drops to the 2,000s when they are sick, but this time it came out at 1,300. The doctor mentioned this level could warrant hospitalization, but since the flu seems to be the cause, we were told to observe them over the weekend and return on Monday if the fever continues.
Can the flu cause the WBC count to drop this low? Now that we are home, I am extremely worried about this number.
Answer:
It is completely understandable that you are worried about a 7-day fever and a white blood cell (WBC) count dropping to 1,300.
Yes, a significant decrease in white blood cells is possible due to the flu:
Influenza A can cause a temporary but sharp drop in WBC levels.
This drop can be even more pronounced for your child since their baseline WBC count is already on the lower end of the normal range.
Typically, as the body recovers from the flu, the WBC count will bounce back to normal.
The doctor likely determined that home observation was safe because the flu is the clear cause of this drop and your child's overall condition appeared stable at the clinic. However, 1,300 is indeed a very low number, and careful observation is required.
Go to the emergency room immediately if you notice any of the following:
Persistent high fever of 38.5°C (101.3°F) or higher
Severe chills or shivering
Difficulty breathing or chest pain
Altered mental status, lethargy, or unusually slow reactions
Any new rashes or bleeding spots (petechiae)
While observing over the weekend, please take the following precautions:
Record your child's temperature every 4 hours.
Ensure plenty of fluid intake (warm water or electrolyte drinks).
Strictly avoid crowded places, as the low WBC count temporarily increases the risk of catching other infections.
Practice thorough hand hygiene at home.
It is highly important that you follow up with your pediatrician on Monday for a re-examination to check how the blood levels are changing. Try not to panic, but observe your child closely and seek an immediate in-person evaluation at the ER if any concerning symptoms arise.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
