Feline Injection-Site Sarcoma and Other Adverse Reactions to Vaccination in Cats

Area of Science:

• Veterinary Medicine
• Immunology
• Oncology

Background:

• Vaccine-associated adverse events (VAAEs) are uncommon but can lead to severe outcomes in cats.
• Feline injection-site sarcomas (FISSs) are a significant concern among VAAEs.
• Understanding VAAEs is crucial for informed owner consent and veterinary decision-making.

Purpose of the Study:

• To review and synthesize current knowledge on VAAEs in cats.
• To provide expert opinion to fill knowledge gaps regarding VAAEs and FISSs.
• To guide veterinarians in implementing optimal vaccination protocols.

Main Methods:

• Comprehensive literature review on VAAEs in feline species.
• Expert consensus and opinion from the European Advisory Board on Cat Diseases (ABCD).
• Analysis of potential causes including immune reactions, administration errors, and manufacturing defects.

Main Results:

• VAAEs stem from aberrant immune responses, local reactions, administration errors, or manufacturing issues.
• Feline injection-site sarcomas (FISSs) are the most severe VAAE, with pathogenesis involving chronic inflammation.
• No vaccine is entirely risk-free, necessitating judicious vaccination schedules.

Conclusions:

• Vaccination frequency should be minimized while maintaining efficacy.
• Vaccine administration best practices include room temperature storage and strategic injection site selection (avoiding the interscapular region).
• Post-vaccinal monitoring is critical for early detection of adverse events.