How catch-up recommendations work under the 2026 three-tier federal immunization framework.
As of January 5, 2026, the federal immunization schedule has been reorganized into three tiers. This guide identifies how catch-up recommendations vary based on whether a vaccine is universally recommended (Tier 1), risk-based (Tier 2), or recommended through shared clinical decision-making (Tier 3). For a full explanation of these categories, see the Citizen's Guide to the 2026 Schedule.
Has your child missed doses of DTaP, Polio, Hib, PCV, MMR, Varicella, or HPV? These are Tier 1 (Universal) vaccines. Standard ACIP catch-up intervals apply.
Does your child have a specific medical condition or environmental risk factor? These may require Tier 2 (High-Risk) catch-up for vaccines like Hep B, Hep A, or Meningococcal. (These vaccines may fall into Tier 2 or Tier 3 depending on individual risk factors — see explanation below.)
Is the vaccine Influenza, COVID-19, or Rotavirus? These are Tier 3 (SCDM) vaccines. Federal policy does not establish a standardized catch-up timeline; these are recommended through shared clinical decision-making.
As of January 2026, federal catch-up recommendations are determined by the specific tier of the immunization in question.
Tier 1 — Recommended for All: Standard ACIP catch-up intervals apply.
Tier 2 — High-Risk Groups Only: Catch-up is indicated only if high-risk criteria are met.
Tier 3 — Shared Clinical Decision-Making: No default catch-up expectation; based on clinical consultation.
Note: Meningococcal disease, Hepatitis A, and Hepatitis B are dually categorized (Tier 2 and Tier 3) depending on age, medical history, and exposure risk.
For vaccines in Tier 1, the clinical objective is to provide protection as quickly as possible using shortened intervals between doses. If a child has missed doses of DTaP, Hib, PCV, Polio (IPV), MMR, HPV (1 dose), or Varicella, standard ACIP catch-up protocols are used to reach completion.
For vaccines in Tier 3 — including Rotavirus, COVID-19, and Influenza — under the 2026 framework, catch-up for these vaccines is guided by shared clinical decision-making rather than a standardized schedule requirement.
For these vaccines, a parent and clinician may decide to initiate a series at any time based on an individual risk-benefit assessment.
Regardless of its Tier 3 status, Rotavirus has strict biological windows. Vaccination cannot be initiated at or after 15 weeks 0 days of age, and the series cannot be completed after 8 months 0 days of age. If these windows have passed, the vaccine is no longer administered.
While federal policy does not establish a standardized catch-up timeline for Tier 3 vaccines, state school-entry requirements may differ. Many states continue to mandate vaccines for school enrollment that the federal government categorizes as Tier 3. Families should verify their specific state's current school-entry requirements through their state health department or school district.
Catch-up for Hepatitis A, Hepatitis B, and Meningococcal vaccines is determined by the child's risk profile.
If a child meets high-risk criteria (e.g., specific underlying medical conditions or potential exposure), catch-up is recommended following standard intervals.
For children not meeting high-risk criteria, these vaccines are recommended through shared clinical decision-making. "Catching up" is a decision pathway guided by individual clinical context rather than a standardized interval schedule.
For more on high-risk definitions, visit the individual disease pages at Hepatitis B or Hepatitis A.