Varicella vaccine from a child with natural varicella, introduced into human embryonic lung cell cultures, adapted to and propagated in embryonic guinea pig cell cultures, and finally propagated in human diploid cell cultures. Japan was among the first countries to vaccinate for chickenpox. The vaccine was first licensed in the United States in 1995. Routine vaccination against varicella zoster virus is also performed in the United States, and the incidence of chickenpox has been dramatically reduced there (from 4 million cases per year in the pre-vaccine era to approximately 400,000 cases per year as of 2005). In Europe most countries do not
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