26 USC 4132 - Definitions and special rules

(a) Definitions relating to taxable vaccines 
For purposes of this subchapter
(1) Taxable vaccine 
The term taxable vaccine means any of the following vaccines which are manufactured or produced in the United States or entered into the United States for consumption, use, or warehousing:
(A) Any vaccine containing diphtheria toxoid.
(B) Any vaccine containing tetanus toxoid.
(C) Any vaccine containing pertussis bacteria, extracted or partial cell bacteria, or specific pertussis antigens.
(D) Any vaccine against measles.
(E) Any vaccine against mumps.
(F) Any vaccine against rubella.
(G) Any vaccine containing polio virus.
(H) Any HIB vaccine.
(I) Any vaccine against hepatitis A.
(J) Any vaccine against hepatitis B.
(K) Any vaccine against chicken pox.
(L) Any vaccine against rotavirus gastroenteritis.
(M) Any conjugate vaccine against streptococcus pneumoniae.
(N) Any trivalent vaccine against influenza.
(O) Any meningococcal vaccine.
(P) Any vaccine against the human papillomavirus.
(2) Vaccine 
The term vaccine means any substance designed to be administered to a human being for the prevention of 1 or more diseases.
(3) United States 
The term United States has the meaning given such term by section 4612 (a)(4).
(4) Importer 
The term importer means the person entering the vaccine for consumption, use, or warehousing.
(b) Credit or refund where vaccine returned to manufacturer, etc., or destroyed 

(1) In general 
Under regulations prescribed by the Secretary, whenever any vaccine on which tax was imposed by section 4131 is
(A) returned (other than for resale) to the person who paid such tax, or
(B) destroyed,

the Secretary shall abate such tax or allow a credit, or pay a refund (without interest), to such person equal to the tax paid under section 4131 with respect to such vaccine.

(2) Claim must be filed within 6 months 
Paragraph (1) shall apply to any returned or destroyed vaccine only with respect to claims filed within 6 months after the date the vaccine is returned or destroyed.
(3) Condition of allowance of credit or refund 
No credit or refund shall be allowed or made under paragraph (1) with respect to any vaccine unless the person who paid the tax establishes that he
(A) has repaid or agreed to repay the amount of the tax to the ultimate purchaser of the vaccine, or
(B) has obtained the written consent of such purchaser to the allowance of the credit or the making of the refund.
(4) Tax imposed only once 
No tax shall be imposed by section 4131 on the sale of any vaccine if tax was imposed by section 4131 on any prior sale of such vaccine and such tax is not abated, credited, or refunded.
(c) Other special rules 

(1) Certain uses treated as sales 
Any manufacturer, producer, or importer of a vaccine which uses such vaccine before it is sold shall be liable for the tax imposed by section 4131 in the same manner as if such vaccine were sold by such manufacturer, producer, or importer.
(2) Treatment of vaccines shipped to United States possessions 
Section 4221 (a)(2) shall not apply to any vaccine shipped to a possession of the United States.
(3) Fractional part of a dose 
In the case of a fraction of a dose, the tax imposed by section 4131 shall be the same fraction of the amount of such tax imposed by a whole dose.
(4) Disposition of revenues from Puerto Rico and the Virgin Islands 
The provisions of subsections (a)(3) and (b)(3) of section 7652 shall not apply to any tax imposed by section 4131.