Scott Weese, DVM, shares the short answer to a common question about half-dosing vaccines, emphazing “we don’t know.” He covers these key elements in this article: a) half-dose efficacy, b) adverse reactions and c) liability.
Source: Worms and Germs, May 28, 2025. Link. About client requests, Weese writes, veterinarians are expected to act professionally and reasonably, which includes communicating with owners and discussing options about their animals’ care. However, veterinarians are not expected (and in fact are expected NOT) to simply do what owners request if it’s medically (or ethically) inappropriate. Regulations and legalities vary by region but in general, owners cannot consent to malpractice, so client consent is not an automatic “get out of jail free card” if a veterinarian does something wrong.
There is there is no evidence that decreasing the vaccine dose will have any impact on adverse events, and no data to know what impact it will have on the desired immune response.”