Q: Should I continue antibiotics for my 5-month-old after the flu, and what do the increased WBC and PLT levels mean?

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:

Hello. I am the mother of a 5-month-old baby. It is currently difficult to visit a pediatrician, so I am asking for advice here.

1. Should I continue giving antibiotics?

Last Monday, my baby was diagnosed with Influenza A and received antiviral treatment. Currently, my baby still has a runny nose and phlegm. We finished the antibiotics prescribed at the time as of yesterday, so I am only giving the runny nose and phlegm medication now. The baby had a lingering mild fever (37.7–38.1°C) that fortunately dropped to normal (below 37.5°C) yesterday. We had been giving antibiotics for almost two weeks in total, and today is the first day we skipped them. Is this okay? I plan to visit the doctor tomorrow but wanted to ask just in case.

1. Regarding the blood test results

In the blood test results this Monday, the platelet count (PLT) increased from 243 to 436, and white blood cells (WBC) increased from 6.26 to 8 compared to the test done last week during the flu. However, the CRP (inflammation marker) has decreased. Symptoms are improving, but I am worried and curious about what caused this increase. Is it a drug reaction? Is my baby okay?

Answer:

Hello. It is completely understandable to be concerned during your baby's recovery from the flu. Here are the answers regarding your baby's condition:

[Regarding Additional Antibiotics]

Since the fever has dropped below 37.5°C and the symptoms are improving, stopping the antibiotics was an appropriate decision.

• The flu is a viral illness, so antibiotics do not treat the flu itself directly.

• Taking antibiotics for nearly two weeks is a sufficient duration for secondary bacterial concerns.

• A runny nose and phlegm can persist for 2 to 3 weeks after recovering from the flu.

[Regarding Blood Test Results]

The increase in PLT (platelets) and WBC (white blood cells) is actually a very good sign!

• Early stage of infection: Platelets and white blood cells often decrease because the viral infection suppresses them.

• Recovery phase: Platelets and white blood cells increase as the body heals and bounces back.

• Decreased CRP: This indicates that the active inflammation in the body is resolving.

Overall, this is a very typical and positive recovery pattern, not a negative drug reaction.

[Precautions & Next Steps]

You are managing the situation very well. It generally takes about 2 to 3 weeks for a full recovery after the flu. When you visit your pediatrician tomorrow for a follow-up, please ask the doctor to perform the following in-person evaluations:

• A stethoscope examination of the lungs to rule out pneumonia as a complication.

• An ear examination to check for acute otitis media (ear infection).

Please continue to monitor your baby closely. If you notice any sudden decrease in your baby's feeding volume, lethargy, or a return of the fever, seek immediate medical evaluation.

For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.

https://fevercoach.us