ICD-10-CM 2027
ICD-10 code for vaccination delay
From the official ICD-10-CM alphabetic index entry “Delay, delayed › vaccination”. Page updated September 29, 2026.
About coding vaccination delay
The ICD-10-CM code for vaccination delay is Z28.9 (Immunization not carried out for unspecified reason).
Within Z28, choose Z28.9 (Immunization not carried out for unspecified reason) only when documentation doesn't support a more specific option: immunization not carried out because of contraindication (Z28.0), immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1), immunization not carried out because of patient decision for other and unspecified reason (Z28.2), underimmunization status (Z28.3) and immunization not carried out for other reason (Z28.8).
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 795 (Normal Newborn, relative weight 0.2022) and DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and 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 vaccination delay ICD-10 codes
What is the ICD-10 code for vaccination delay?
- Z28.9 — Immunization not carried out for unspecified reason.
Is Z28.9 billable?
- Yes. Z28.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z28.9 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 Z28.9 a CC or MCC?
- No. Z28.9 is neither a CC nor an MCC under MS-DRG v44.0.