Background: The consequences of the epidemiology of varicella for zoster epidemiology are still debated. We therefore compared the frequency of herpes zoster in an adult population with virtually no varicella zoster virus (VZV) exposure with that in the general population (GP).
Methods: We performed a national, multicenter, observational, exposed versus nonexposed, comparative study. The nonexposed population consisted of members of contemplative monastic orders (CMO) of the Roman Catholic Church living in 40 isolated monasteries in France. The exposed population consisted of a sample of the GP representative of the French population in terms of age group, sex, socio-occupational categories, and regions.
Results: The primary analysis population comprised 920 members of CMO (41.5% nuns; mean age, 64.2 years) and 1533 members of the GP (51.9% women; mean age, 64.6 years). The reported frequency of zoster was 16.2% among CMO and 15.1% in the GP (P = .27, adjusted for sex and age). The reported mean age of onset of zoster was 54.8 and 48.6 years, respectively (P = .06).
Conclusions: This study failed to demonstrate an increased risk or earlier onset of zoster in members of CMO not exposed to VZV, compared with that in the GP. Although adults highly exposed to VZV could have a reduced risk of zoster, compared with the GP, our results suggest that the opposite is not true: adults not exposed to VZV are not at increased risk of zoster when compared with the GP, challenging the relevance of the assumptions and forecasts of current epidemiological models.