ICD-10-CM 2027
ICD-10 code for Unvaccinated for covid-19
From the official ICD-10-CM alphabetic index entry “COVID-19 › unvaccinated (for)”. Page updated September 29, 2026.
About coding Unvaccinated for covid-19
The ICD-10-CM code for Unvaccinated for covid-19 is Z28.310 (Unvaccinated for COVID-19).
Within Z28.31 (underimmunization for COVID-19 status), Z28.310 is specifically for Unvaccinated for COVID-19. Related codes cover Partially vaccinated for COVID-19 (Z28.311).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Unvaccinated for covid-19 ICD-10 codes
What is the ICD-10 code for Unvaccinated for covid-19?
- Z28.310 — Unvaccinated for COVID-19.
Is Z28.310 billable?
- Yes. Z28.310 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z28.310 be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is Z28.310 a CC or MCC?
- No. Z28.310 is neither a CC nor an MCC under MS-DRG v44.0.