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.
12 to 15 years Yorkshire terriers, known as Yorkies, live an average of  12 to 15 years. The small dogs often suffer from health problems including bronchitis, easily upset stomachs, eye infections and tooth decay. They also tend to have spine problems and can easily herniate disks.