Have Cat Questions? Ask a Cat Vet Online.
Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry that your sister is having issues with Giardia in one of her cats. I'm sorry to inform you that this particular vaccine has been removed from the market due to lack of sales. ...probably for several reasons but the primary one is because of lack of efficacy. When it was given, it appeared to reduce the shedding in some patients to some degree but controlled, non-manufacturer studies, didn't demonstrate any clinical benefit.
The Giardia vaccine is on the AAHA (American Animal Hospital Association) "not recommended" list because of lack of efficacy so many vets didn't recommend its use.
So, even if it were available, it's not likely to have helped your sister's situation, unfortunately. Deb