Additives used in the production of vaccines may include. 1  suspending fluid (e.g. sterile water, saline, or fluids containing protein); 2  preservatives and stabilizers to help the vaccine remain unchanged (e.g. albumin, phenols, and glycine); and. 3  adjuvants or enhancers to help the vaccine to be more effective.
The other element is a standard Yorkie that falls under or over the expected weight and/or size range. Breed standards have changed. The AKC used to list a minimum weight of 4 pounds (1.81 kg). Now, there is only a maximum weight of 7 pounds (3.17 kg) for a full grown, adult Yorkie. Even with this change on paper, most Yorkshire Terriers fit into the 3 to 7 lb. (1.36 kg to 3.17 kg) range. A dog smaller than this, fully grown, would be considered too small and may have size related health issues.
If you are looking for a dog like a Yorkie, but a bit larger. I would suggest something like a Lakeland Terrier, Irish Terrier, Welsh Terrier, Wire Fox Terrier, Norfolk Terrier, Cairn Terrier, Scottish Terrier, Australian Terrier, or the Norwich Terrier.