Tail Vaccination in Cats

Each year, 1–10 of 10,000 vaccinated cats in the U.S. are diagnosed with feline injection-site sarcoma (FISS). Without radical surgery, most cats die of local recurrence or distant metastasis. Surgery may be associated with prolonged recovery, disfigurement, and loss of function. This pilot study evaluated alternative vaccination sites based on preference of oncologists, ease of injection, and serologic responses.

Specialists in medical, surgical, and radiation oncology ranked the desirability of 11 vaccination sites, based solely on treating FISS. The tail was selected as an alternative to currently recommended vaccination sites and was compared with the distal hindlimb, the most popular traditional site.

Adult cats (n = 60) from a trap-neuter-return program were enrolled in this study. All received a SC modified-live FVRCP virus vaccine and an SC inactivated rabies vaccine (RV). Half were vaccinated in the dorsal distal third of the tail and half in the distal hindlimb. Feline vaccination acceptance scores, calculated from several observed behaviors, did not significantly differ between the 2 vaccination sites. All cats initially seronegative to feline panleukopenia virus developed protective antibody titers 1–2 months following vaccination. For the RV, 1 cat receiving tail vaccination failed to develop acceptable antibody titers, which may represent the previously reported expected failure rate (2.8%) seen in international travel testing. Given ease of administration and immunogenicity between vaccination sites, further consideration should be given to distal tail vaccination.

This excellent and thought-provoking pilot study provided important data that should be tested in a larger cat population. The true incidence of FISS remains debatable, but FISS can be devastating and seen worldwide. Interestingly, the authors, who described their procedure well, demonstrated that tail vaccination was accepted by a significantly higher proportion of cats than distal hindlimb vaccination, making the former a viable and relatively easy procedure for veterinarians. While perhaps not an obvious vaccination site, the tail deserves further investigation, as the study also showed it had equally good immunologic responses, was easy to monitor for swelling, and is a favored site by oncologists should FISS management be required.—Andrew Sparkes, BVetMed, PhD, DECVIM, MRCVS

Tail vaccination in cats: A pilot study.Hendricks CG, Levy JK, Tucker SJ, et al. J FELINE MED SURG 16:275-280, 2014.

This capsule is part of the Global Edition of Clinician's Brief