TEXAS VET NEWS By Dr. Bob Judd, DVM and the Texas Farm Bureau Texas Farm Bureau Radio Network

Today on the program I am going to start a five-part series on equine vaccines and how well they work.  A vaccine is supposed to make an animal resistant to disease; however, you may not realize that all vaccines are not 100% effective.  Most people think vaccines are going to prevent the animal from getting infected with the disease and even though that is the case with some vaccines, it is not the case with all of them.  Some of the vaccines may only help to aid in controlling a certain disease or decreasing clinical signs.  It is important to understand this concept because many people get upset with their veterinarian if their horse gets a disease they vaccinated for when it is not your veterinarian’s fault. 

The first vaccine we are going to talk about is equine influenza vaccine.  Equine influenza is a highly contagious disease that affects the respiratory system and causes a high fever, a dry cough, and nasal discharge.  It is recommended to vaccinate horses with influenza vaccine every 6 months.  However, it is difficult to completely prevent influenza because there are many strains of the disease and these strains can mutate quickly and as these strains change, the vaccine may not prevent the disease.  Although influenza vaccines have been used for years and have been shown to be effective in experimental studies, a recent paper in Veterinary Clinics of North America indicates there are not any actual field trials indicating the vaccines are effective.  However, they have been shown to decrease clinical signs and decrease shedding of the virus after infection, so with influenza vaccine the best you can hope for is a less severe illness and decreased transmission to other horses.

Date Published: 6/29/2009 9:18:00 AM