I choose to provide my animals with their initial round of vaccinations and no further vaccinations. Based on my research, the lack of readily available information on the duration of vaccination antibodies suggests to me that they last much longer than what pharmaceutical companies may lead us to believe. Conducting long-term trials is not currently in their best interest, as it would potentially disrupt the yearly vaccination practices. In my opinion, ensuring that cats and dogs are fed high-quality, grain-free food is just as crucial as vaccination. I have personally cared for multiple cats that initially had cat flu but managed to become symptom-free and keep other animals in my household free from the flu through a combination of a nutritious diet and a stress-free environment. However, I encourage you to conduct your own research and not solely rely on information from random sources on the internet when it comes to the well-being of your cats.