Research overview: vaccines against feline herpesvirus and calicivirus

Feline herpesvirus-1 and feline calicivirus are major causes of upper respiratory disease in cats, and core vaccines against them reduce the severity of illness, though they do not fully prevent infection or eliminate the carrier state, particularly for herpesvirus, which establishes lifelong latency. Calicivirus vaccines face the additional challenge of substantial viral strain diversity. This overview compiles the virology and vaccinology literature rather than one citation, describing why these vaccines mitigate rather than wholly prevent disease, how latency and strain variation complicate control, and the special concern of virulent systemic calicivirus outbreaks. It matters because respiratory vaccines substantially reduce the burden of common, contagious feline diseases even as the biology of these viruses limits the prospect of complete protection.