Smallpox (B03) ICD-10-CM
The B03 code range covers smallpox with 1 ICD-10-CM diagnosis codes. 1 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
- In 1980 the 33rd World Health Assembly declared that smallpox had been eradicated.
- The classification is maintained for surveillance purposes.
Codes in the B03 Range 1 codes · 1 billable
- B03 Smallpox
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the B03 range.
Orthopoxvirus
A genus of the family POXVIRIDAE, subfamily CHORDOPOXVIRINAE, comprising many species infecting mammals. Viruses of this genus cause generalized infections and a rash in some hosts. The type species is VACCINIA VIRUS.
Smallpox
An acute, highly contagious, often fatal infectious disease caused by an orthopoxvirus characterized by a biphasic febrile course and distinctive progressive skin eruptions. Vaccination has succeeded in eradicating smallpox worldwide. (Dorland, 28th ed)
Smallpox Vaccine
A VACCINIA VIRUS vaccine used for immunization against SMALLPOX. It is now recommended only for laboratory workers exposed to SMALLPOX VIRUS. Certain countries continue to vaccinate those in the military service. Rare complications most often associated with older generation smallpox vaccines include VACCINIA, secondary bacterial infections, and ENCEPHALOMYELITIS. Because MONKEYPOX VIRUS and SMALLPOX VIRUS are both ORTHOPOXVIRUS and are closely related smallpox vaccines provide effective CROSS-PROTECTION against MPOX, MONKEYPOX (https://www.cdc.gov/poxvirus/monkeypox/clinicians/smallpox-vaccine.html).
Variola virus
A species of ORTHOPOXVIRUS causing infections in humans. No infections have been reported since 1977 and the virus is now believed to be virtually extinct.
About the B03 Code Range
The ICD-10 code B03 is used specifically to identify cases of smallpox, a serious viral infection formerly widespread but now eradicated. This code captures all forms and variations of smallpox documented in medical records.
B03 covers smallpox under various names, including common synonyms like Variola major, hemorrhagic smallpox, and flat-type smallpox. It also includes less typical presentations such as modified smallpox, Alastrim, and smallpox without rash. By using the ICD-10 code for smallpox, healthcare professionals and medical coders accurately document this specific viral infection, distinguishing it from other pox-related or rash-causing diseases. This precise classification supports clear communication in healthcare records and epidemiologic tracking when dealing with any suspected or diagnosed cases of smallpox.
Questions About This Page
How many billable codes are in the B03 range?
Of the 1 codes in this range, 1 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the B03 range classify?
The range classifies smallpox. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
