We characterised the global landscape of smallpox vaccination at a subnational scale by integrating data on current demography with historical smallpox vaccination programme features (coverage and cessation dates) from eradication documents and published literature. We analysed this landscape to identify the factors that were most associated with geographical heterogeneity in current vaccination coverage. We considered how smallpox vaccination history might translate into age-specific susceptibility profiles for orthopoxviruses under different vaccination effectiveness scenarios.
We found substantial global spatial heterogeneity in the landscape of smallpox vaccination, with vaccination coverage estimated to range from 7% to 60% within admin-1 regions (ie, regions one administrative level below country) globally, with negligible uncertainty (99·6% of regions have an SD less than 5%). We identified that geographical variation in vaccination coverage was driven mostly by differences in subnational demography. Additionally, we found that susceptibility for orthopoxviruses was highly age specific based on age at cessation and age-specific coverage; however, the age profile was consistent across vaccine effectiveness values.
The legacy of smallpox eradication can be observed in the current landscape of smallpox vaccine protection. The strength and longevity of smallpox vaccination campaigns globally, combined with current demographic heterogeneity, have shaped the epidemiological landscape today, revealing substantial geographical variation in orthopoxvirus susceptibility. This study alerts public health decision makers to non-endemic regions that might be at greatest risk in the case of widespread and sustained transmission in the 2022 monkeypox outbreak and highlights the importance of demography and fine-scale spatial dynamics in predicting future public health risks from orthopoxviruses.
US National Institutes of Health and US National Science Foundation.
方法:我们通过将当前人口统计数据与根除文件和已发表文献中的历史天花疫苗接种计划特征(覆盖率和停止日期)相结合,在国家以下范围对全球天花疫苗接种情况进行了表征。我们分析了这种情况,以确定当前疫苗接种覆盖率中与地理异质性最相关的因素。我们考虑了在不同的疫苗接种有效性情况下,天花疫苗接种史如何转化为正痘病毒的年龄特异性易感性。
结果:我们在天花疫苗接种的景观中发现了大量的全球空间异质性,在管理-1地区,疫苗接种覆盖率估计为7%至60%(即,区域低于国家/地区的一个行政级别)全球,具有可忽略的不确定性(99·6%的区域的SD小于5%)。我们发现,疫苗接种覆盖率的地理差异主要是由国家以下人口统计学的差异驱动的。此外,我们发现,基于戒烟年龄和年龄特异性覆盖率,正痘病毒的易感性具有高度的年龄特异性;然而,不同疫苗有效性值的年龄分布是一致的.
结论:根除天花的遗产可以在天花疫苗保护的现状中观察到。全球天花疫苗接种运动的强度和寿命,结合当前的人口异质性,塑造了今天的流行病学景观,揭示了正痘病毒易感性的重大地理差异。这项研究提醒公共卫生决策者注意在2022年猴痘爆发中广泛和持续传播的情况下可能面临最大风险的非地方病地区,并强调了人口学和精细尺度空间动态在预测正痘病毒未来公共卫生风险方面的重要性。
背景:美国国立卫生研究院和美国国家科学基金会。