Department of Woman and Child Health and Public Health - Public Health Area, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
Section of Hygiene, University Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, Rome, Italy.
Environ Res. 2022 Mar;204(Pt C):112342. doi: 10.1016/j.envres.2021.112342. Epub 2021 Nov 5.
Most countries initially deployed COVID-19 vaccines preferentially in elderly populations. We aimed to evaluate whether population-level vaccine effectiveness is heralded by an increase in the relative proportion of deaths among non-elderly populations that were less covered by vaccination programs.
We collected data from 40 countries on age-stratified COVID-19 deaths during the vaccination period (1/14/2021-5/31/2021) and two control periods (entire pre-vaccination period and excluding the first wave).
We meta-analyzed the proportion of deaths in different age groups in vaccination versus control periods in (1) countries with low vaccination rates; (2) countries with age-independent vaccination policies; and (3) countries with standard age-dependent vaccination policies.
Countries that prioritized vaccination among older people saw an increasing share of deaths among 0-69 year old people in the vaccination versus the two control periods (summary proportion ratio 1.32 [95 CI% 1.24-1.41] and 1.35 [95 CI% 1.26-1.44)]. No such change was seen on average in countries with age-independent vaccination policies (1.05 [95 CI% 0.78-1.41 and 0.97 [95 CI% 0.95-1.00], respectively) and limited vaccination (0.93 [95 CI% 0.85-1.01] and 0.95 [95 CI% 0.87-1.03], respectively). Proportion ratios were associated with the difference of vaccination rates in elderly versus non-elderly people. No significant changes occurred in the share of deaths in age 0-49 among all 0-69 deaths in the vaccination versus pre-vaccination periods.
The substantial shift in the age distribution of COVID-19 deaths in countries that rapidly implemented vaccination predominantly among elderly provides evidence for the population level-effectiveness of COVID-19 vaccination and a favorable evolution of the pandemic towards endemicity with fewer elderly deaths.
大多数国家最初优先为老年人接种 COVID-19 疫苗。我们旨在评估在疫苗接种计划覆盖范围较小的非老年人群中，相对比例的死亡人数增加是否预示着人群水平疫苗有效性。
我们从 40 个国家收集了疫苗接种期间（2021 年 1 月 14 日至 5 月 31 日）和两个对照期间（整个疫苗接种前期间和排除第一波）按年龄分层的 COVID-19 死亡数据。
我们对疫苗接种与对照期间不同年龄组死亡人数进行荟萃分析，包括：（1）疫苗接种率较低的国家；（2）年龄独立疫苗接种政策的国家；（3）标准年龄依赖疫苗接种政策的国家。
优先为老年人接种疫苗的国家，在疫苗接种与两个对照期间，0-69 岁人群的死亡比例增加（综合比例比 1.32[95%置信区间 1.24-1.41]和 1.35[95%置信区间 1.26-1.44]）。在年龄独立疫苗接种政策的国家，平均没有这种变化（1.05[95%置信区间 0.78-1.41 和 0.97[95%置信区间 0.95-1.00]），且疫苗接种范围有限（0.93[95%置信区间 0.85-1.01]和 0.95[95%置信区间 0.87-1.03]）。比例比与老年与非老年人群之间疫苗接种率的差异有关。在疫苗接种与疫苗接种前期间，0-49 岁年龄组的所有 0-69 岁死亡人数中，死亡人数的比例没有明显变化。
在迅速在老年人中广泛实施疫苗接种的国家中，COVID-19 死亡的年龄分布发生了重大变化，这为 COVID-19 疫苗接种的人群水平效果提供了证据，并预示着大流行朝着与老年人群死亡人数减少相关的地方性流行方向发展。
