Z28.310
Unvaccinated for COVID-19
Z28.310 (also written Z28310) is a billable ICD-10-CM diagnosis code for unvaccinated for COVID-19. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 17 codes in category Z28 (Immunization not carried out and underimmunization status). The Alphabetic Index lists it under 5 entries. Its coding notes include a Use additional code instruction and a Code also instruction.
Use additional code
Add the listed code as a secondary code, if known.
- code, if applicable, to identify:
- immunization not carried out because of contraindication (Z28.0-)
- immunization not carried out because of patient decision for other and unspecified reason (Z28.2-)
- immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1)
- immunization not carried out for other reason (Z28.8-)
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Hospice: not accepted as primary
Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Supplementary or additional code, not allowed as principal diagnosis.
Includes
Further defines or gives examples of the content of the category.
- vaccination not carried out
Notes
- These codes should not be used for individuals who are not eligible for the COVID-19 vaccines, as determined by the healthcare provider.
Also from chapter/block level (3 notes)
- Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
- (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
- (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 5 entries