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As summer ends and schools are back in session, pediatric practices enter one of the busiest seasons for vaccinations. September brings a surge of visits for flu shots, catch-up immunizations, and, in recent years, RSV immunization for infants. While these services are essential for public health, billing for them can be a source of denials and underpayments if handled incorrectly.
Below are key vaccines commonly administered in the fall, their associated CPT and ICD-10 codes, and the most frequent billing challenges pediatric practices should watch for.
1. Influenza (Flu) Vaccines
CPT Codes (examples for 2025–2026 season):
90656 – Influenza virus vaccine, quadrivalent, preservative-free, 0.5 mL, IM
90674 – Influenza virus vaccine, quadrivalent, preservative-free, MDCK-derived, 0.5 mL, IM
90686 – Influenza virus vaccine, quadrivalent, preservative-free, 0.5 mL, pediatric/adolescent IM
ICD-10 Codes:
Z23 – Encounter for immunization
Billing Pitfalls:
Forgetting to append the vaccine administration code (90460 for first vaccine given with provider counseling under 18; 90461 for each additional vaccine component; 90471/90472 when counseling is not provided).
Omitting the NDC (National Drug Code) on claims, which is increasingly required by payers for vaccine reimbursement.
2. COVID-19 Vaccines (Fall 2025 Boosters)
CPT Codes (examples):
91321 – COVID-19 vaccine, mRNA, 2025–2026 formulation
90480 – Administration of COVID-19 vaccine
ICD-10 Code:
Z23 – Encounter for immunization
Billing Pitfalls:
Using an outdated CPT code from a prior formulation. Payers will deny claims tied to past seasonal vaccine codes.
Not linking Z23 as the primary diagnosis for vaccine claims.
3. RSV Immunization for Infants
Since 2023, RSV prevention for babies has expanded beyond supportive care to include monoclonal antibody protection. By 2025, two primary options are available:
Nirsevimab (Beyfortus):
A monoclonal antibody given as a single dose to infants under 8 months during RSV season, and to certain high-risk children up to 19 months.
CPT Codes: 90380 (RSV monoclonal antibody, 50 mg) / 90381 (RSV monoclonal antibody, 100 mg)
Administration Code: 96372 (therapeutic injection, subcutaneous or intramuscular)
ICD-10 Code: Z29.11 (Encounter for prophylactic immunotherapy for respiratory syncytial virus [RSV])
Enflonsia (Merck):
A new monoclonal antibody option for RSV protection in infants, typically used in similar age ranges as nirsevimab.
CPT Code (anticipated): 90382 (RSV monoclonal antibody, Enflonsia, per dose)
Administration Code: 96372
ICD-10 Code: Z29.11 (Encounter for prophylactic immunotherapy for RSV)
Billing Pitfalls:
Confusing preventive immunization (Z23) with RSV prophylaxis (Z29.11). Claims may be denied if the wrong diagnosis code is used.
Not distinguishing between 90380/90381 (Beyfortus) and the new code for Enflonsia (90382).
Failing to include the correct NDC number for the specific product and dosage administered.
Key Billing Challenges to Watch For in Fall 2025
NDC Number Entry Errors:
Some payers require the exact 11-digit NDC code for vaccine claims. Entering it in the wrong field, truncating digits, or using the carton NDC instead of the vial NDC are all common mistakes.
Double-check that your practice’s EHR/RCM system is configured to populate the correct NDC.
Incorrect Administration Coding:
For children under 18, 90460/90461 should be used when counseling is documented.
For patients 18 and older or when no counseling is provided, use 90471/90472.
For RSV monoclonal antibodies, use 96372.
Using Outdated Codes:
Each flu, COVID, and RSV season may bring updated CPT codes. Always confirm your system has the current year’s codes before claims go out.
Diagnosis Code Mismatches:
Vaccines should be paired with Z23 as the primary diagnosis. RSV monoclonal antibody prophylaxis must use Z29.11.
Final Thoughts
September is a high-volume month for vaccines, and small mistakes can lead to big losses in time and revenue. Ensuring proper use of current CPT codes, ICD-10 codes, and accurate NDC numbers will help practices avoid payer denials.
At Physician Xpress, Inc., our pediatric-specific EHR and RCM services help practices track coding changes, reduce vaccine claim rejections, and keep revenue flowing smoothly—even during the busiest months of the year.
