Getting chicken pox naturally protects you from the vaccine virus! And mass chicken pox vaccination is expected to cause a major epidemic of the vaccine form of chicken pox, known as herpes-zoster.

M. Brisson (a,b) N. J. Gaya (a), W. J. Edmunds (a,b), and N. J. Andrews (a) Exposure to varicella boosts immunity to herpes-zoster: implications for mass vaccination against chickenpox Vaccine Volume 20, Issues 19-20, 7 June 2002, Pages 2500-2507

(a) Immunisation Division, PHLS Communicable disease Surveillance Centre, 61 Colindale Avenue, London NW9 5EQ, UK (b) Department of Economics, City University, London EC1V 3HD, UK

We present data to confirm that exposure to varicella boosts immunity to herpes-zoster. We show that exposure to varicella is greater in adults living with children and that this exposure is highly protective against zoster (Incidence ratio=0.75, 95% CI, 0.63-0.89). The data is used to parameterise a mathematical model of varicella zoster virus (VZV) transmission that captures differences in exposure to varicella in adults living with and without children. Under the 'best-fit' model, exposure to varicella is estimated to boost cell-mediated immunity for an average of 20 years (95% CI, 7-41years). Mass varicella vaccination is expected to cause a major epidemic of herpes-zoster, affecting more than 50% of those aged 10-44 years at the introduction of vaccination.