Why Do We Need Separate Chicken-Pox And Shingles Vaccines?

On the other hand, the existing chicken-pox vaccine, aimed at children, contains a whole, live, but weakened varicella zoster virus. “Live viral vaccines tend to work better in children,” says Ann Arvin, an infectious-disease specialist at Stanford University. (Arvin has consulted for both GlaxoSmithKline and Merck, which makes the chicken-pox vaccine.) The reasons are not entirely well understood, but children have a different mix of immune cells than adults, and live viruses tend to provide better, broader immunity through life.