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
Reactive airway disease Reactive airway disease Reactive airway disease is a general term used by many physicians to label patients with symptoms similar to those of asthma. It is most commonly used when a physician is hesitant about formally diagnosing a patient with asthma, which is most prevalent in the pediatric setting for a variety of reasons. While some physicians may use RAD and asthma synonymously, this causes controversy, since RAD can not be used as a real diagnosis for physicians. An exact definition of the condition does not exist. Individuals that are typically labeled as having reactive airway disease, or RAD, generally