Vaccine Oka varicella-zoster virus genotypes are monomorphic in single vesicles and polymorphic in respiratory tract secretions.

We previously found that, after immunization with vaccine Oka varicella-zoster virus, virus obtained from a single vesicle were monomorphic, and virus obtained from different individuals were heterogeneous. Here we show that virus obtained from the lungs of a patient were a mixture of vaccine Oka variants. We hypothesize that complications after immunization are unlikely to be caused by expansion of a single, biologically more virulent clone of virus that either pre-exists in the vaccine or develops after random mutation of different clones. We hypothesize that some clones are more trophic than others for skin.