CVX API

Look up CVX vaccine codes from the CDC.

Overview

CVX (Vaccine Administered) codes are maintained by the CDC and identify vaccines administered to patients. FHIRfly provides fast lookups against the CDC's CVX code set.

Endpoints

Method	Path	Description
GET	`/v1/cvx/:code`	Single CVX lookup
POST	`/v1/cvx/_batch`	Batch lookup (up to 100)
GET	`/v1/cvx/shapes`	List available response shapes

Single Lookup

Look up COVID-19 Moderna vaccine

Request

Node.js

import { Fhirfly } from "@fhirfly-io/terminology";

const client = new Fhirfly({ apiKey: "YOUR_API_KEY" });

const result = await client.cvx.lookup("207");
console.log(result.data);

Response

JSON

{
  "data": {
    "code": "207",
    "code_system": "http://hl7.org/fhir/sid/cvx",
    "display": "COVID-19, mRNA, LNP-S, PF, 100 mcg/0.5mL dose or 50 mcg/0.25mL dose",
    "fhir_coding": {
      "code": "207",
      "display": "COVID-19, mRNA, LNP-S, PF, 100 mcg/0.5mL dose or 50 mcg/0.25mL dose",
      "system": "http://hl7.org/fhir/sid/cvx"
    },
    "full_vaccine_name": "SARS-COV-2 (COVID-19) vaccine, mRNA, spike protein, LNP, preservative free, 100 mcg/0.5mL dose or 50 mcg/0.25mL dose",
    "is_covid_vaccine": true,
    "last_updated_by_cdc": "2023-10-24",
    "notes": "Original monovalent Moderna adult vaccine. FDA rescinded all doses for US use 4/18/2023. Continue to used to record historic US Moderna vaccines and those administered in non-US locations (includes tradename Spikevax)",
    "status": "inactive",
    "vaccine_type": "mRNA"
  },
  "meta": {
    "legal": {
      "attribution_required": false,
      "citation": "CDC National Center for Immunization and Respiratory Diseases. Accessed 2026-01-14 via FHIRfly.",
      "license": "public_domain",
      "source_name": "CDC Immunization"
    }
  }
}

Common CVX Codes

Code	Vaccine
208	Pfizer-BioNTech COVID-19
207	Moderna COVID-19
140	Influenza, seasonal
03	MMR
21	Varicella

Batch Lookup

Look up multiple CVX codes in a single request (up to 100):

Look up multiple vaccines

Request

Node.js

import { Fhirfly } from "@fhirfly-io/terminology";

const client = new Fhirfly({ apiKey: "YOUR_API_KEY" });

const result = await client.cvx.lookupMany(["207","208","140"]);
console.log(result.data.results);

Response

JSON

{
  "count": 3,
  "results": [
    {
      "input": "207",
      "code": "207",
      "status": "ok",
      "data": {
        "display": "COVID-19, mRNA, Moderna",
        "status": "inactive"
      }
    },
    {
      "input": "208",
      "code": "208",
      "status": "ok",
      "data": {
        "display": "COVID-19, mRNA, Pfizer",
        "status": "inactive"
      }
    },
    {
      "input": "140",
      "code": "140",
      "status": "ok",
      "data": {
        "display": "Influenza, seasonal, injectable",
        "status": "active"
      }
    }
  ],
  "meta": {
    "legal": {
      "license": "public_domain"
    }
  }
}

Batch with `shape=full`

When using shape=full on batch requests, the response includes meta.source with provenance information:

POST /v1/cvx/_batch?shape=full

{
  "count": 3,
  "results": [
    {
      "input": "207",
      "code": "207",
      "status": "ok",
      "data": { "display": "COVID-19, mRNA, Moderna", "status": "inactive" }
    }
  ],
  "meta": {
    "source": {
      "name": "CDC Immunization",
      "url": "https://www2a.cdc.gov/vaccines/iis/iisstandards/vaccines.asp?rpt=cvx",
      "version": "monthly",
      "fhirfly_updated_at": "2026-03-01T03:00:00Z"
    },
    "legal": {
      "license": "public_domain",
      "attribution_required": false
    }
  }
}

Response Shapes

Control the level of detail in responses with the shape query parameter:

Shape	Description
`compact`	Code, display, status
`standard`	+ full_vaccine_name, notes, vaccine_type, fhir_coding
`full`	+ ingest metadata

# Minimal data
GET /v1/cvx/207?shape=compact

# Standard data (default)
GET /v1/cvx/207?shape=standard

# Full data with provenance
GET /v1/cvx/207?shape=full

See Response Shapes for field details.

NDC Crosswalks

CVX vaccine codes can be enriched with NDC crosswalk data using the include=crosswalks query parameter. When included, the response adds a crosswalks.ndc array linking the vaccine code to specific NDC product codes.

GET /v1/cvx/207?include=crosswalks

{
  "data": {
    "code": "207",
    "display": "COVID-19, mRNA, LNP-S, PF, 100 mcg/0.5mL dose or 50 mcg/0.25mL dose",
    "status": "inactive",
    "crosswalks": {
      "ndc": [
        {
          "ndc": "80777-0273-99",
          "mvx": "MOD",
          "begin_date": "2020-12-18",
          "end_date": "2023-08-31"
        }
      ]
    }
  }
}

This is useful for mapping between vaccine codes and specific drug products, particularly in claims processing and inventory management workflows.

Required Scopes

cvx.read - Single and batch lookups