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
Lyme disease they finish treatment. These symptoms can last for more than 6 months. This condition is called post-treatment lyme disease syndrome. As of 2016 the reason for the lingering symptoms was not known; the condition is generally managed similarly to fibromyalgia or chronic fatigue syndrome. In dogs, a serious long-term prognosis may result in glomerular disease, which is a category of kidney damage that may cause chronic kidney disease. Dogs may also experience chronic joint disease if the disease is left untreated. However, the majority of cases of Lyme disease in dogs result in a complete recovery with, and sometimes without,