Some other things to be aware of:
• Modified-live vaccines can begin to lose potency once they are mixed, so be sure to use them promptly — within 45 minutes to a few hours, depending on the product and situation. Consult with your veterinarian on proper handling and administration techniques.
• Some of the harsher disinfectants, when used to clean syringes, can kill a vaccine if the residue hasn’t been removed. Ultraviolet light from direct sunlight can have the same effect.
• Unless it’s stated on the label that “duration of immunity studies have been established” for a vaccine, it’s unknown exactly how long a vaccine will protect an animal. Many times, the vaccine label will simply take a default position and recommend “annual re-vaccination.” But that can be misleading, because producers might look at “annual revaccination” and think that one shot is all that is needed when, in fact, a booster is often needed as well. Again, consult with your veterinarian.
• It’s important to understand antibody interference with vaccines. Antibodies that are already in the animal from colostrum or a previous vaccination can bind to the agents in a vaccine known as antigens, which basically tells the rest of the immune system that “everything is already taken care of, so don’t worry about it.” It’s like flipping an off-switch at a time when the animal needs extra protection. This is a problem with some diseases more than others — BVD is an example where existing antibodies can block a vaccine. Your veterinarian is an important resource for letting you know when to time the vaccines.