In the absence of satisfactory combined vaccine testing methods that can be put into use, new testing methods should be developed as soon as possible to determine the content or potency of each component.
In the absence of satisfactory joint vaccine testing methods to be put into use, new testing methods should be developed as soon as possible to determine the content or effectiveness of each of the parts.
In the absence of a satisfactory method for the detection of combined vaccine, new detection methods should be developed as soon as possible to determine the content or potency of each component.