I read a while ago that tetatus and diphtheria toxoids only represent about 50% of proteins in vaccines but I cannot find the original reference. Please, if someone knows about it share the info.
A mixed combined vaccine is given in form of Diphtheria and Tetanus Toxoid given together as Td in adults for protections against Diphtheria and Tetanus .for more detailed check the attached ref:
Vaccine are calculated based on Lf per dose along with the adjuvants. The potency unit on each batch of vaccine is calculated by invivo antibody induction / challenge method and must be passes the regulatory requirement like USP, EU, IP before it release. The QC test for potency unit and safety parameters are much important criteria than the protein concentration on the priscribed Lf.
I found the reference I was looking for: Article More than a Toxin: Protein Inventory of Clostridium tetani T...
Tetanus toxin (TeNT) tetanus vaccines range from 72% to 17% with regard to all other C. tetani proteins, depending on the vaccine and method of estimation. As the article says: tetanus toxoid vaccines are more than a toxin.