M1299 Influenza Immunization (HCPCS) Reimbursement

HCPCS Level II code M1299 represents documentation that an influenza immunization was administered or previously received. This code matters nationally as influenza vaccination is a cornerstone of public health efforts to reduce seasonal morbidity and mortality and to track vaccine delivery across outpatient settings. Accurate use of M1299 supports clinical records, public health reporting, and payment workflows for routine immunization services.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find context on the clinical purpose of the code, common sites of service for influenza vaccination, and the typical administrative uses of the code in claims submissions. The publication summarizes benchmarking and payer coverage considerations where available, clarifies how the code is positioned relative to immunization service lines, and highlights operational points relevant to billing and documentation. Data not available in the input will be noted as such; the focus remains on national applicability rather than state-level policy.

Billing Code Overview

HCPCS Level II code M1299 denotes influenza immunization administered or previously received. This code is used to document the provision of an influenza vaccine or the record that a patient previously received an influenza immunization.

Service type: Immunization administration
Typical site of service: Ambulatory clinics, physician offices, community vaccination sites, pharmacies, and other outpatient settings where influenza vaccines are given

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Clinical Context

A typical patient is an adult presenting to a primary care clinic or community pharmacy during influenza season requesting or scheduled for an influenza vaccination. The patient arrives for a brief visit, checks in, completes screening questions for allergies, recent illnesses, prior severe reactions to vaccines, current medications (including anticoagulants), and pregnancy status. A licensed vaccinator (family medicine physician, nurse practitioner, physician assistant, or pharmacist) verifies immunization history, obtains informed consent, documents lot number and manufacturer, administers the influenza vaccine intramuscularly (usually deltoid), and observes the patient for 10–15 minutes for immediate adverse reactions. Documentation includes vaccine type, date, administration site, route, dose, lot number, expiration, and the patient’s consent and counseling. Billing uses HCPCS Level II code M1299 to indicate an influenza immunization administered or previously received when specific product-level codes are not applicable or when reporting the service in settings that use a general vaccine administration code. Typical workflow may include co-administration of other routine vaccines, counseling for next season, and updating the state immunization registry.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when additional work or time beyond typical vaccine counseling or administration is documented and meets payer criteria for unusual service intensity.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Family Medicine	Common primary care specialty that administers influenza vaccines in clinic settings.
`208000000X`	Internal Medicine	Internists routinely provide adult immunizations and document administration.
`363LP0800X`	Pharmacist	Pharmacists in many states administer influenza vaccines in pharmacies.
`103T00000X`	Nurse Practitioner	NPs commonly provide vaccinations in ambulatory settings.
`367500000X`	Physician Assistant	PAs frequently perform vaccine administration under supervising physician protocols.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Data not available in the input.`	Data not available in the input.	Data not available in the input.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`90471`	Immunization administration (includes percutaneous, intradermal, subcutaneous, or intramuscular) when given alone	Used when a single vaccine administration is billed for the visit; often paired with vaccine coding when product-specific codes are reported.
`90472`	Each additional vaccine administration	Used if more than one vaccine is administered during the same visit, as an add-on to `90471`.
`90460`	Immunization administration, counseling by physician or other qualified health care professional; first vaccine/toxoid component, 18 years or older, when counseling is provided	Used when significant face-to-face counseling about the vaccine is separately documented for adults and payer allows counseling codes.
`90461`	Immunization administration, each additional vaccine/toxoid component, counseling by physician or other qualified health care professional; 18 years or older	Add-on to `90460` for additional vaccines requiring counseling.
`99070`	Supplies and materials provided by physician over and above those usually included with the office visit	May be used by some payers when supplies for vaccine administration are billed separately (payer policies vary).

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Summary & Overview

HCPCS M1299: Influenza Immunization Administered or Previously Received