Cocci Vaccine - CocciVac -- Is it effective?

[Jensownzoo]

Marek's vaccine does NOT infect the birds, and does help protect them from the tumors produced in birds infected with Marek's disease.  For most of us with backyard flocks, it's the only useful vaccine.  Mary

It doesn't infect the bird directly, but instead allows them to become infected and not die...meaning they are free to saturate the area with the active virus. If they had died, the window of opportunity for the virus to replicate and spread itself around would be much, much shorter. The more the virus replicates, the more chances it has to evolve factors that increase its virulence. It is a really tangled subject. I'm still evolving a definitive opinion on vaccinating for it.

 

[junebuggena]

It doesn't infect the bird directly, but instead allows them to become infected and not die...meaning they are free to saturate the area with the active virus. If they had died, the window of opportunity for the virus to replicate and spread itself around would be much, much shorter. The more the virus replicates, the more chances it has to evolve factors that increase its virulence. It is a really tangled subject. I'm still evolving a definitive opinion on vaccinating for it.

Exactly. A lot of people don't realize that poultry vaccines don't work the same way that vaccines do in mammals. With the Marek's vaccine, vaccinated birds can still contract the virus, but they don't exhibit symptoms. If they contract the virus, you will never actually know, and they will become infectious carriers, shedding the virus for their entire lives.

 

[lazy gardener]

And from my reading, vaccinated birds are also carriers of a much more lethal strain of Mareks. The supervirus from vaccinated carriers kills in a matter of days, compared to the wild strains that take much longer to kill, or perhaps don't kill at all, allowing the birds naturally infected to go on and develop immunity.