Ridecamp: Re: [RC] West Nile Vaccine

'Keep in mind the protocol for using this vaccine determines the efficacy. If you get the initial shot but don't follow up with the booster in the proper time period, than your horse is not protected and, if your horse contracts WNV, it won't count against the vaccine. If I can find a webpage where these statistics are posted I'll put it out on Ridecamp, but I don't think such a site exists right now. Vetmed and my personal veterinarian, who has dealt with over 40 horses who have contracted the disease, have been my sources of information. That, plus over 200 current articles I've read about the vaccine. When a neighbor's horse dies from this disease, it tends to perk up one's interest in the subject. Next time I'll see my Vet I will ask her exactly where she's getting her efficacy numbers from.'

Howard, I think you have finally touched the bias I have been talking about. The protocol doesn't determine the efficacy. The data you are describing is typically done to support safety issues surrounding a new vaccine. Are there side effects? If so, how often will you see them and what are they? This type of reporting also helps track horses who are vaccinated and can accurately report the Prevalence of WNV in THIS PARTICULAR POPULATION OF HORSES IF the appropriate follow up studies are done on these animals (which is usually cost prohibitive). See, its just not as simple as: animal A gets vaccinated and doesn't get sick, therefore vaccine is safe and efficacious. That's just one arm of the study. For a fair study, you have to compare that group to a number of others: namely an equal group of healthy, unvaccinated horses. In order to show efficacy, the unvaccinated horses should have a statistically significant higher incidence of contracting WNV than the vaccinated group. All I'm saying is that I haven't seen that literature yet. You can go on and on from here....what about unhealthy vaccinated horses, or the healthy horse that missed a booster. Not to mention, the vaccine may have differing efficacies depending on where you live in the country. I can appreciate that you are concerned particularly with WNV in your backyard, but the data is simply not yet clear cut. All we can do is what we feel is best for our own horses.

That said, as an ENT doc, I have personally watched the H.Flu vaccine in people, completely wipe out bacterial epiglottis in children just my generation. So I know vaccines can work.. you mentioned Polio and Smallpox, both good examples of highly successful vaccines. And the complete data on the Incidence and Prevalence of these diseases is well documented (hell, that's why healthcare is so damn expensive).

Re: [RC] West Nile Vaccine - Jennifer Judkins