Viruses having weakened ability to establish and/or maintain latency and their use as live vaccines are described. The vaccines have one or more alterations in genes that provide continued virus replication but that inhibit latency. The vaccine materials and methods for their construction are exemplified with the varicella zoster virus. Deletion of a significant portion from both copies of the varicella zoster gene ORF63 was shown to inhibit establishment of a latent infection from a live vaccine form of the virus. Insertion of an additional ORF62 gene which is partially truncated with the ORF63 deletion inhibited establishment of latency and allowed normal growth of the virus. Other desirable viral antigen encoding sequence(s) and/or cytokine genes advantageously may replace deleted genetic material to enhance a desired immunological response. Aspects of the discovery pertain to live vaccines of other viruses, and can provide a variety of vaccines having greater safety.