The varicella-zoster virus (VZV) causes two distinct diseases:varicella (i.e. “chickenpox”) and herpes zoster (i.e. “shingles”) .Chickenpox, which primarily occurs during childhood, causes anitchy rash for about a week. Complications from chickenpox are relatively infrequent and include pneumonia, bacterial surinfection and encephalitis. Shingles predominantly occurs at older age. It isthe result of a reactivation of VZV, which after chickenpox remains latently present in neural ganglia. This reemergence of the viruscan be assumed to be a consequence of waning cellular immunity.Shingles is characterized by a painful rash on the body and causes on average a more severe and longer-lasting loss of quality of lifethan chickenpox.
Evidence increasingly suggests that chickenpox vaccination of children risks redistributing health risks toward older generations. Varicella-ShinglesStudy
Varicella vaccination is less effective than the natural immunity that existed in pre-vaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease. Read Goldman GS, King PG study.