US Patent 11185579 Oral vaccine against ruminant respiratory disease comprising polyvinylpyrrolidone

The present invention relates to an oral vaccine against respiratory disease in ruminants, comprising live attenuated Mannheimia haemolytica bacteria and a Polyvinylpyrrolidone (PVP). The addition of PVP significantly improves the protective effect of vaccination on lung scores after a challenge infection. Further the PVP allows vaccination by a method of mass administration, such as by oral route via a drink. In addition the invention relates to methods for the preparation of such a vaccine, to methods for the vaccination of ruminants employing such a vaccine, and to medical uses of a composition comprising M. haemolytica bacteria.