The article details the history of the anti-Marek’s disease vaccine for chickens which was first introduced in 1970. We’re on the third version of this vaccine within a decade. It has stopped working. The reason? The virus has mutated to evade the vaccine.
And just for your information it has been peer reviewed. https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002198
PLOS Biology tested the theory that vaccines are driving the mutation of the herpesvirus causing Marek’s disease in chickens. To do that, they vaccinated 100 chickens and kept 100 unvaccinated. All of the birds were then infected with varying strains of the virus. Some strains were more virulent and dangerous than others.
Over the course of the birds’ lives, the unvaccinated ones shed more of the least virulent strains into the environment, while the vaccinated ones shed more of the most virulent strains.
“The findings suggest that the Marek’s vaccine encourages more dangerous viruses to proliferate. This increased virulence might then give the viruses the means to overcome birds’ vaccine-primed immune responses and sicken vaccinated flocks.”
This could very much be the case in the next 10-15 years with the Covid vaccines.