Where is the evidence (links to controlled studies) which demonstrate a multi valent vaccine is more harmful than multiple single valent vaccines? In humans, the CDC refutes the commonly held worry that multi valent vaccines are more harmful than single valent vaccines.
One thing everyone needs to keep in mind is that vaccines are not just the antigen; a vaccine for rabies is not just inactivated rabies virus it contains other components which can all elicit immune responses. Some scientific literature has reported other components in vaccines (other than the antigen) can cause autoimmune like responses (stimulate antibodies observed during autoimmune responses).
‘ASIA’ – Autoimmune/inflammatory syndrome induced by adjuvantsAdjuvants and autoimmunityAutoimmunity induced by adjuvant hydrocarbon oil components of vaccineI prefer my dogs to receive only 1 dose of adjuvants, preservatives, and other components in vaccines every 3 years (or longer) than to receive multiple doses of these other vaccine components by giving multiple single antigen vaccines. Until there is definitive evidence of the source (which components in vaccines) of vaccinosis I prefer to vaccinate less (fewer injections) which means multiple antigens per injection. If we see any adverse reactions to a vaccine (a mixture prepared by a particular manufacturer) will cause us to research that particular mixture and find another manufacturer (with its own mixture) of that vaccine.
A multi valent vaccine for x, y, and z is like canned chicken soup; each manufacturer will have its own recipe, sources of ingredients, and manufacturing process. If I have an adverse reaction to this can of chicken soup, it could be chicken, that particular source of chicken, how the manufacturer processed the chicken, or the source of savory in the poultry seasoning in that can of chicken soup.