Humoral and Cell-Mediated Immune Responses in Healthy Children After One or Two Doses of Varicella Vaccine

Abstract

This study compared the immune responses of healthy children to one or two doses of Oka/Merck varicella vaccine. Both cell-mediated and humoral immune responses were significantly stronger 1 year later among children given two doses 3 months apart than among those given a single dose. Long-term follow-up studies are needed to determine whether two doses of vaccine indeed provide more complete and more durable protection than a single dose against breakthrough varicella in healthy children.