Varicella vaccine were vaccinated as children were still protected from varicella." However, since only one out of five Japanese children were vaccinated, the annual exposure of these vaccinees to children with natural chickenpox boosted the vaccinees' immune system. In the United States, where universal varicella vaccination has been practiced, the majority of children no longer receive exogenous (outside) boosting, thus, their cell-mediated immunity to VZV (varicella zoster virus) wanes—necessitating booster chickenpox vaccinations. As time goes on, boosters may be necessary. Persons exposed to the virus after vaccine tend to experience milder cases of chickenpox. Catching "wild" chickenpox as a child has been
Riggs' disease Riggs' disease Riggs' disease, also known as pyorrhea of a toothsocket or gingivitis expulsiva, is a historical term for periodontitis (gum disease), The condition was described as a purulent inflammation of the dental periosteum. It was named after American dentist John Mankey Riggs (1811–1885). Riggs' disease was said to produce the progressive necrosis of the alveoli and looseness of the teeth. The teeth may become very loose and fall out of the sockets. Mark Twain wrote briefly about Riggs' disease in his short essay, "Happy Memories of the Dental Chair", in which he claims to have been examined by Dr.