Companion Animal Welfare

Cat Welfare and Injection Site Sarcoma

Feline injection site sarcoma is a rare but serious complication of vaccination. Modern protocols have significantly reduced incidence while maintaining vaccine protection.

Key Facts

Feline injection site sarcomas are rare, occurring in approximately 1 in 10,000-30,000 cats
Modern adjuvant-free vaccines and changed injection sites reduce sarcoma risk
Recommended injection sites have moved to limbs where surgery is more effective if needed
Any lump at an injection site persisting more than 4 weeks should be investigated
Excision must be wide and aggressive as local recurrence is common

Welfare Considerations

Injection site sarcoma causes significant welfare harm but is rare and the risk-benefit balance strongly favours vaccination. Using modern vaccine protocols and monitoring injection sites reduces this risk further.

What You Can Do

Use modern adjuvant-free vaccines where available
Have injection sites monitored at post-vaccination checks
Seek veterinary assessment for any lump at an injection site persisting more than 4 weeks
Never forgo vaccination due to sarcoma fear - the risk-benefit balance favours vaccination