Marinelli Isabella, van Lier Alies, de Melker Hester, Pugliese Andrea, van Boven Michiel
Dipartimento di Matematica, Università di Trento, Trento, Italy; Basque Center for Applied Mathematics, Bilbao, Spain.
Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Epidemics. 2017 Jun;19:1-12. doi: 10.1016/j.epidem.2016.11.001. Epub 2016 Nov 22.
Studies into the impact of vaccination against the varicella zoster virus (VZV) have increasingly focused on herpes zoster (HZ), which is believed to be increasing in vaccinated populations with decreasing infection pressure. This idea can be traced back to Hope-Simpson's hypothesis, in which a person's immune status determines the likelihood that he/she will develop HZ. Immunity decreases over time, and can be boosted by contact with a person experiencing varicella (exogenous boosting) or by a reactivation attempt of the virus (endogenous boosting). Here we use transmission models to estimate age-specific rates of reactivation and immune boosting, exogenous as well as endogenous, using zoster incidence data from the Netherlands (2002-2011, n=7026). The boosting and reactivation rates are estimated with splines, enabling these quantities to be optimally informed by the data. The analyses show that models with high levels of exogenous boosting and estimated or zero endogenous boosting, constant rate of loss of immunity, and reactivation rate increasing with age (to more than 5% per year in the elderly) give the best fit to the data. Estimates of the rates of immune boosting and reactivation are strongly correlated. This has important implications as these parameters determine the fraction of the population with waned immunity. We conclude that independent evidence on rates of immune boosting and reactivation in persons with waned immunity are needed to robustly predict the impact of varicella vaccination on the incidence of HZ.
针对水痘带状疱疹病毒（VZV）疫苗接种影响的研究越来越关注带状疱疹（HZ），据信在感染压力降低的接种人群中，带状疱疹的发病率正在上升。这一观点可以追溯到霍普 - 辛普森假说，该假说认为一个人的免疫状态决定了他/她患带状疱疹的可能性。免疫力会随着时间下降，可以通过与患水痘的人接触（外源性增强）或病毒的再激活尝试（内源性增强）来增强。在此，我们使用传播模型，利用荷兰的带状疱疹发病率数据（2002 - 2011年，n = 7026）来估计特定年龄的再激活率和免疫增强率，包括外源性和内源性的。通过样条估计增强率和再激活率，使这些量能够根据数据得到最佳信息。分析表明，具有高水平外源性增强以及估计的或零内源性增强、恒定的免疫丧失率和随年龄增加的再激活率（老年人每年超过5%）的模型与数据拟合最佳。免疫增强率和再激活率的估计值高度相关。这具有重要意义，因为这些参数决定了免疫减弱人群的比例。我们得出结论，需要关于免疫减弱人群免疫增强率和再激活率的独立证据，才能有力地预测水痘疫苗接种对带状疱疹发病率的影响。
