THE EFFECTS OF VACCINATION IN AN AGE-DEPENDENT MODEL FOR VARICELLA AND HERPES-ZOSTER

The varicella-zoster virus (VZV) is responsible for. the infectious di seases varicella and herpes tester, more commonly known as chickenpox and shingles. The United States Food and Drug Administration recently approved a VZV vaccine for use in children to prevent chickenpox. The VZV vaccine was tested in Japan, Korea, and the United States, and the se extensive experimental investigations led to final approval in the United States. In this paper, an age-dependent model for varicella and herpes tester is formulated. Using statistics for the United States, parameter values for the model are estimated and numerical solutions a re calculated. The effects of various control strategies, designed to decrease the number of individuals susceptible to varicella and tester , are investigated. In particular, the effect of vaccination on the av erage age of infection, the average number of infections per person du ring their lifetime, and the ratio of number of tester cases after con trol to those before control are investigated.