Skip to main content

Licensed vaccines afford varying levels of protection. It is important to read and understand product labeling.

Label indications: Data must fully support label indications and accurately reflect the expected performance of the product.

History of the Single Tier Label Claim 

All label claims for veterinary biologicals are based on the statistical significance and clinical relevance of efficacy data provided by manufacturers. Historically, veterinary biologicals were assigned 1 of 4 tiers of effectiveness, depending on the magnitude of the observed protective effects:

  • for the prevention of infection

  • for the prevention of disease

  • as an aid in the prevention of disease

  • as an aid in the control/reduction of disease.  

Distinctions between these levels were not well understood by many users of biological products, resulting in potential misinterpretation of label information.

In response to this concern, the USDA began using a single statement in 2015 (e.g., “This product has been shown to be effective for the vaccination of healthy animals X weeks of age or older against * * *”) to replace the previous 4 tiers of effectiveness. The rigor with which the USDA evaluates efficacy data for statistical and clinical meaningfulness has not changed.

In addition to a standardized claim statement, a standardized Product Compilation Summary of the efficacy and safety studies used to support licensure is available for review on this Single Tier User Guide.
As part of a movement in 2015 toward single-tier effectiveness statements, 9CFR 112.5(b) was amended to require publication of efficacy and safety study summaries on the USDA APHIS Licensed Veterinary Biologic Products website. This website also provides instruction for licensees, permittees, and applicants preparing to submit efficacy and safety data summaries.

A summary of a single study is known herein as an Individual Study Summary (ISS). It is prepared by the licensee and reviewed/edited/cleared by the Center for Veterinary Biologics (CVB) for standard content and appearance. All of the ISSs applicable to a single biological product are then compiled into a Product Compilation Summary (PCS), which is posted to The compilation is performed by the CVB.

Scope of Products Affected by Single-Tier

  • Vaccines (including prescription platform products), bacterins, toxoids, and immunomodulators are included under the scope of the new rule.

  • Products exempted include: antibody products, diagnostic test kits, autogenous, and allergenic extract*



Reviewed by the AAEP Infectious Disease Committee in 2021.