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
Chronic Lyme disease whereby pseudomedicine is legislated into practice. The term "chronic Lyme disease" is distinct from untreated late-stage Lyme disease, which can cause arthritis, peripheral neuropathy and/or encephalomyelitis. Chronic Lyme disease is also distinct from the 'post-treatment Lyme disease syndrome' (PTLDS)", when symptoms linger after standard antibiotic treatments. PTLDS is estimated to occur in less than 5% of people who had Lyme disease and were treated. In many cases there is no objective evidence that people who believe they have chronic Lyme have ever been infected with Lyme disease: standard diagnostic tests for infection are often negative. While it is undisputed people