Immunization not carried out and underimmunization status (Z28)
The ICD-10 code Z28 and its subcategories are used to document cases where immunization has not been carried out or where underimmunization status applies. These codes cover various reasons for missed vaccines, ranging from medical contraindications to patient or caregiver refusal, as well as other specific circumstances.
The codes under Z28 specify why an immunization was not administered, such as contraindications (Z28.0), patient acute or chronic illness (Z28.01, Z28.02), allergies (Z28.04), or immune compromise (Z28.03). Patient decision–related codes (Z28.1 to Z28.29) include refusal due to beliefs or unspecified reasons, with detailed synonyms clarifying common scenarios like "vaccination declined" or "no consent" for vaccines including tetanus, measles, and COVID-19. The underimmunization status codes (Z28.3 and subcodes) address incomplete immunization series, particularly for COVID-19 vaccines, helping coders identify patients who are unvaccinated or partially vaccinated. Other codes reflect immunization not done due to vaccine unavailability, caregiver refusal, or unspecified reasons, with synonyms like “vaccine product out of stock” or “influenza vaccination not done.” These codes enable precise recording of immunization status, critical for public health tracking and patient care planning.
- Z28 - Immunization not carried out and underimmunization sta
- Z28.0 - Immunization not carried out because of contraindica
- Z28.2 - Immunization not carried out because of patient deci
- Z28.3 - Underimmunization status
- Z28.31 - Underimmunization for COVID-19 status
- Z28.8 - Immunization not carried out for other reason
Factors influencing health status and contact with health services (Z00–Z99)
Persons with potential health hazards related to communicable diseases (Z20-Z29)
Z28 Immunization not carried out and underimmunization status
Z28.0 Immunization not carried out because of contraindication
- Z28.01 Immunization not carried out because of acute illness of patient
- Z28.02 Immunization not carried out because of chronic illness or condition of patient
- Z28.03 Immunization not carried out because of immune compromised state of patient
- Z28.04 Immunization not carried out because of patient allergy to vaccine or component
- Z28.09 Immunization not carried out because of other contraindication
- Z28.1 Immunization not carried out because of patient decision for reasons of belief or group pressure
Z28.2 Immunization not carried out because of patient decision for other and unspecified reason
- Z28.20 Immunization not carried out because of patient decision for unspecified reason
- Z28.21 Immunization not carried out because of patient refusal
- Z28.29 Immunization not carried out because of patient decision for other reason
Z28.3 Underimmunization status
Z28.31 Underimmunization for COVID-19 status
- Z28.310 Unvaccinated for COVID-19
- Z28.311 Partially vaccinated for COVID-19
- Z28.39 Other underimmunization status
Z28.8 Immunization not carried out for other reason
- Z28.81 Immunization not carried out due to patient having had the disease
- Z28.82 Immunization not carried out because of caregiver refusal
- Z28.83 Immunization not carried out due to unavailability of vaccine
- Z28.89 Immunization not carried out for other reason
- Z28.9 Immunization not carried out for unspecified reason
Immunization not carried out and underimmunization status (Z28)
Instructional Notations
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- vaccination not carried out
Code Also
A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
- , if applicable, encounter for immunization safety counseling Z71.85
