»Poliovirus Vaccine Inactivated conforms to the regulations of the federal Food and Drug Administration concerning biologics (630.1to 630.6)(see Biologics á1041ñ).It is a sterile aqueous suspension of inactivated poliomyelitis virus of Types 1,2,and 3.The virus strains are grown separately in primary cell cultures of monkey kidney tissue,and from a virus suspension with a virus titer of not less than 106.5TCID50measured in comparison with the U.S.Reference Poliovirus of the corresponding type,are inactivated so as to reduce the virus titer by a factor of 10-8,and after inactivation are combined in suitable proportions.

No extraneous protein,capable of producing allergenic effects upon injection into human subjects,is added to the final virus production medium.If animal serum is used at any stage,its calculated concentration in the final medium does not exceed 1part per million.Suitable antimicrobial agents may be used during the production.The single strain harvests or virus pools prior to inactivation meet the requirements of the specific mouse,guinea pig,and rabbit tests for absence of Bvirus and Mycobacterium tuberculosis,and the tissue culture test for absence of SV-40virus.The single strain or trivalent virus pools after inactivation meet the requirements of the specific tissue culture and monkey tests for absence of active poliovirus,the mouse test for absence of lymphocytic choriomeningitis virus,and the tissue culture safety test for absence of SV-40virus or other active viruses.The Vaccine meets the requirements of the specific monkey potency test by virus neutralizing antibody production,based on the U.S.Reference Poliovirus Antiserum,such that the ratio of the geometric mean titer of the group of monkey serums representing the vaccine to the mean titer value of the reference serum is not less than 1.29for Type 1,1.13for Type 2,and 0.72for Type 3.