Project Management Department, Shionogi & Co., Ltd., Osaka, Japan.
Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
PLoS One. 2024 Aug 12;19(8):e0306891. doi: 10.1371/journal.pone.0306891. eCollection 2024.
COVID-19 is an infectious disease that continues to spread worldwide. A precise estimation of the cases and deaths due to COVID-19 would allow for appropriate consideration of healthcare resource allocation, public health response, and vaccination and economic planning, to minimize social damage. In this study, we analyzed the progression of COVID-19 cases and deaths until January 2022 in 156 countries using a nonlinear mixed-effect model based on the SIR framework. Given the major changes in mortality from infection, risk of re-infection and social responses, the analysis was limited to the period before the emergence of the Omicron variant. The impact of infection prevention measures in various countries was assessed, with a specific focus on estimating the effectiveness of lockdowns, where the effect was assumed to change over time. By accounting for excess mortality, our analysis allowed the estimation of unreported cases and deaths, and thus providing a more comprehensive understanding of the impact of pandemic. In the analysis, we identified gross domestic product (GDP), proportion of people aged 65 years or older, latitude of the capital city on transmissibility of infection, and city population and cardiovascular death rate on mortality rate as significant influencing factors. Furthermore, the differences in transmissibility and mortality rates by variants and the effect of vaccination on the mortality rate were assessed. The transmissibility has increased by odds ratios of 1.2 to 1.4 in Beta, Gamma, and Delta variants; mortality rate has increased by odds ratios of 1.7, 2.2, and 1.4 in Beta, Gamma, and Delta variants, respectively; and vaccination decreased the mortality rate by odds ratios of 0.4 and 0.1 in Delta and other variants, respectively.
新型冠状病毒肺炎（COVID-19）是一种持续在全球范围内传播的传染病。准确估计 COVID-19 病例和死亡人数，有助于合理分配医疗资源、采取公共卫生措施以及规划疫苗接种和经济活动，从而将社会损害降至最低。本研究采用基于 SIR 框架的非线性混合效应模型，分析了截至 2022 年 1 月 156 个国家/地区的 COVID-19 病例和死亡的进展情况。鉴于感染死亡率、再次感染风险和社会应对措施的重大变化，本分析仅限于奥密克戎变异株出现之前的时间段。评估了各国感染预防措施的影响，特别关注封锁措施的效果，假设其随时间而变化。通过考虑超额死亡率，我们的分析可以估计未报告的病例和死亡人数，从而更全面地了解大流行的影响。在分析中，我们确定了国内生产总值（GDP）、65 岁及以上人口比例、首都城市纬度、城市人口和心血管死亡率作为传染病传播性和死亡率的重要影响因素。此外，还评估了不同变异株的传播性和死亡率差异以及疫苗接种对死亡率的影响。贝塔、伽马和德尔塔变异株的传染性分别增加了 1.2 至 1.4 倍；贝塔、伽马和德尔塔变异株的死亡率分别增加了 1.7、2.2 和 1.4 倍；接种疫苗分别使德尔塔和其他变异株的死亡率降低了 0.4 和 0.1 倍。
