COVID-19疫苗在减少严重症状和死亡方面表现出显著疗效,尽管它们在预防传播方面的有效性因人口的年龄特征和主要变体而异。这项研究评估了COVID-19疫苗接种运动在西班牙巴斯克地区的影响,在全球老年人中比例第四高。使用住院的流行病学数据,ICU入院,死亡人数,和疫苗接种覆盖率,我们校准了四个版本的常微分方程模型,并对年龄结构和传递函数进行了不同的假设。通过将疫苗接种率设置为零而所有其他参数保持恒定来模拟反事实无疫苗情况。最初的疫苗接种计划估计已阻止了46,000至75,000例住院,6,000至11,000ICU入院,15,000至24,000人死亡,将这些结果减少73-86%。最显著的影响发生在2021年第三季度,与Delta变种的主导地位和疫苗接种率超过60%相吻合。敏感性分析显示,疫苗接种覆盖率对避免结果的影响比疫苗效力更大。总的来说,巴斯克地区的疫苗接种运动显著降低了严重的COVID-19结局,与全球估计保持一致,并展示不同建模方法的稳健性。
COVID-19 vaccines have demonstrated significant efficacy in reducing severe symptoms and fatalities, although their effectiveness in preventing transmission varies depending on the population\'s age profile and the dominant variant. This study evaluates the impact of the COVID-19 vaccination campaign in the Basque Country region of Spain, which has the fourth highest proportion of elderly individuals worldwide. Using epidemiological data on hospitalizations, ICU admissions, fatalities, and vaccination coverage, we calibrated four versions of an ordinary differential equations model with varying assumptions on the age structure and transmission function. Counterfactual no-vaccine scenarios were simulated by setting the vaccination rate to zero while all other parameters were held constant. The initial vaccination rollout is estimated to have prevented 46,000 to 75,000 hospitalizations, 6,000 to 11,000 ICU admissions, and 15,000 to 24,000 deaths, reducing these outcomes by 73-86%. The most significant impact occurred during the third quarter of 2021, coinciding with the Delta variant\'s dominance and a vaccination rate exceeding 60%. Sensitivity analysis revealed that vaccination coverage had a more substantial effect on averted outcomes than vaccine efficacy. Overall, the vaccination campaign in the Basque Country significantly reduced severe COVID-19 outcomes, aligning with global estimates and demonstrating robustness across different modeling approaches.