Nirsevimab-alip (Beyfortus) — CPB 1038 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 1038 covering nirsevimab-alip (Beyfortus) for RSV prevention, effective October 11, 2025. Here's what changes for billing teams.

The updated Aetna nirsevimab-alip coverage policy expands and clarifies the medical necessity criteria for CPT 90380 and CPT 90381—the two primary codes for seasonal Beyfortus dosing. It also adds detail around second-season eligibility, post-surgical redosing, and the interaction with maternal RSV vaccination status. If your practice bills for pediatric RSV prophylaxis, this policy governs your reimbursement and your exposure to claim denial on every Beyfortus administration you bill to Aetna.

Quick-Reference Table

Aetna Nirsevimab-alip Coverage Criteria and Medical Necessity Requirements 2025

CPB 1038 Aetna's framework for Beyfortus follows the CDC's Advisory Committee on Immunization Practices (ACIP) recommendations. Aetna considers a single intramuscular injection of nirsevimab-alip medically necessary for RSV lower respiratory tract disease prevention when the patient meets one of four distinct clinical scenarios.

Scenario 1: Infants under 8 months in their first RSV season (or high-risk infants 8–11 months)

This is your broadest coverage bucket. The infant qualifies when maternal RSV vaccine was not received, maternal RSV vaccine status is unknown, or the infant was born fewer than 14 days after maternal vaccination. It also covers infants whose mother received RSV vaccine during a prior pregnancy. One critical gate: the infant must not have previously received clesrovimab-cfor, nirsevimab-alip, or palivizumab.

The "high-risk" definition for 8–11 month infants includes hemodynamically significant congenital heart disease, intensive care admission, and requiring oxygen at discharge. These map directly to ICD-10 range Q20.0–Q28.9 and Z99.81 on your claim.

Scenario 2: Clinical judgment cases when maternal vaccine was received 14+ days before birth

This is where the policy gets nuanced—and where most denials will originate if your team isn't careful. Aetna's Aetna nirsevimab-alip coverage policy acknowledges that most infants need protection from either the maternal vaccine or Beyfortus, not both. But it carves out exceptions for clinical judgment.

Those exceptions include: mothers with immunocompromising conditions who may not have mounted an adequate immune response; mothers living with HIV (B20) who have conditions associated with reduced transplacental antibody transfer; and infants who had cardiopulmonary bypass, ECMO (CPT 33946–33959), or exchange transfusion (CPT 36450, 36455, 36456) that caused loss of RSV antibodies. Infants with substantially increased risk for severe RSV disease also qualify under this scenario.

Document the clinical rationale in the chart before billing. Aetna will look for it.

Scenario 3: Second-season eligibility for children 8–19 months

Children aged 8 to 19 months can qualify for a second RSV season dose if they meet high-risk criteria. The covered conditions are: chronic lung disease of prematurity requiring medical support (corticosteroids, diuretics, or supplemental oxygen) in the six months before the second RSV season; severe immunocompromise; cystic fibrosis with severe lung disease or weight-for-length below the 10th percentile; and American Indian or Alaska Native children.

One important coverage rule here: if the child received clesrovimab-cfor or palivizumab in their first RSV season, nirsevimab-alip is still billable in the second season. If clesrovimab-cfor or palivizumab was given in the same second season, nirsevimab-alip is not covered.

Scenario 4: Post-surgical redosing

Children undergoing cardiac surgery with cardiopulmonary bypass, ECMO, or exchange transfusion during or entering their first or second RSV season may receive an additional Beyfortus dose. The child must be stable post-surgery. This is an important carve-out for your pediatric cardiology and cardiac surgery billing teams. Code the ECMO or bypass procedure (CPT 33946–33959) or exchange transfusion (CPT 36450–36456) on the same or adjacent claim to support medical necessity.

The core CPT codes for the drug administration are CPT 90380 (0.5 mL dose) and CPT 90381 (1 mL dose). Use Z29.11 as your primary diagnosis code for the prophylactic encounter. Back it up with the condition-specific ICD-10 that drove the eligibility.

Coverage Indications at a Glance

Aetna Nirsevimab-alip Billing Guidelines and Action Items 2025

The effective date of October 11, 2025 means this policy is live now. Don't wait until next RSV season to update your workflows.

CPT, HCPCS, and ICD-10 Codes for Nirsevimab-alip Under CPB 1038

Covered CPT Codes (When Selection Criteria Are Met)

Other CPT Codes Related to CPB 1038

These codes are referenced in the policy as clinically relevant—particularly for post-surgical redosing eligibility and exchange transfusion scenarios. They are not independently covered for Beyfortus administration, but they support medical necessity documentation and appear on claims alongside the primary Beyfortus codes.

Key ICD-10-CM Diagnosis Codes