Novel Strain-Based Triple Inactivated Vaccine Confers Rapid Neutralizing Immunity to Feline Multisystemic Pathogens With Two-Dose Regimen.

Abstract

The rapid global increase in companion animal populations and the rising risks of zoonotic diseases necessitate urgent advancements in veterinary vaccines. In China, over 100 million domestic cats are vulnerable to three deadly pathogens: feline calicivirus (FCV), feline herpesvirus type 1 (FHV-1), and feline panleukopenia virus (FPV). Existing trivalent vaccines face challenges, such as antigenic mismatches, supply chain inefficiencies, and delayed regional adaptability, highlighting the need for localized solutions. In response, we present Meowonder, the first fully indigenous triple feline vaccine developed using contemporary Chinese isolates of FCV, FHV-1, and FPV. Through inactivation and formulation with a proprietary adjuvant, Meowonder has achieved superior safety and immunogenicity and has been approved for the Chinese market. In controlled trials, two doses of Meowonder resulted in robust neutralizing antibody responses, surpassing commercial vaccines in preventing clinical symptoms such as oral ulcers, respiratory distress, and tissue damage after exposure. Clinical studies involving 1818 cats confirmed the efficacy of the two-dose regimen across various ages and regions, with no significant benefit from a third dose. Significantly, Meowonder reduced viral shedding and maintained healthy leukocyte levels following FPV exposure, which is crucial for environments with multiple cats. Histopathological analyses indicated complete protection against FCV-associated mucosal necrosis, FPV-induced intestinal lesions, and FHV-1-driven respiratory damage. By aligning vaccine antigens with circulating strains, Meowonder addresses regional virological diversity and sets a new standard for feline immunization. It offers a scalable solution to enhance the health of companion animals in China and beyond.