There has been discussion on another board regarding Mareks. I think there is a lot of misinfortion out there. I know people on this board have discussed it also. Yesterday, I e-mailed Dr. Fulton at MSU. He specializes in poultry. He was very helpful when we were hit with Mareks last year. This is what I asked him: Last year I had a bird with Mareks. You very kindly advised me about her health issues via e-mail. I thank you very much for that. I would like to ask you about vaccinations. I hatched 23 chicks this year in an incubator and vaccinated all for Mareks. I have poultry acquaintances that are sure that having these chicks vaccinated will infect any bird they ever come in contact with for the rest of their lives. I believe it is so predoninate in the environment that I would be crazy not to vaccinate. As an expert, would you please tell me if these vaccinated chicks will turn out to be "Typhoid Mary's." Would you please tell me what the risks of vaccination are and if vaccinated birds are a real threat to others? Thank You For Your Time He very kindly sent me a prompt response. This is what he said: Dear Jody: I understand your and your poultry pal's concerns but you are right in your thinking about Marek's disease. Marek's disease virus is everywhere. In fact, the vaccination of poultry for Marek's disease is a race to see which virus is going to win in the bird.....the vaccine virus or the disease causing virus. While it is true that Marek's disease vaccinated birds are infected with the vaccine virus for life, I am not aware of them shedding the vaccine virus. The good news is that the vaccine viruses do not cause disease so your chickens are safe and not "Typhoid Marys." The other vaccines used in poultry do not cause "Typhoid Marys" except for almost all vaccines used to protect against Infectious Laryngotracheitis. Chickens vaccinated with those vaccines can shed the vaccine virus and the vaccine virus will make non-vaccinated chickens sick. As for vaccinating your chickens for other diseases, I only recommend vaccinating chickens against diseases you have had or that are in your area. In most cases, that only includes fowl pox. Please note that chicken pox is a human disease and not a chicken disease. The virus that causes chicken pox in humans does not cause disease in chickens nor do humans get it from chickens. Hope this helps, R. M. Fulton, D.V.M., Ph.D. There is a lot of misinformation out there on the web regarding vaccinations and Mareks. People get the effects of one vaccine confused with another, etc. If birds vaccinated for Mareks are so contagious, why are they allowed in the shows? The virus in the Mareks vaccine is not the same one that causes the disease. It is just similar enough to create immunity. We all should check our sources regarding such things before passing on misinformation. Last year when my flock had an issue with Mareks, I contacted local vets and vets at poultry departments of universities with ag departments. They all told me the same thing. And all of the university people told me that Dr Fulton was the foremost authority on it. I think I can trust my sources. I hope that Dr. Fultons response can help people on this board as well as the other forum I posted it on.