论文标题
衡量欧洲和美国共同19号死亡率的变化
Measuring the Change in European and US COVID-19 Death Rates
论文作者
论文摘要
通过为美国和欧洲国家的累积案件和死亡数据拟合了COVID-19的隔室ODE模型，我们发现，在美国大多数地区，案件死亡率似乎至少降低了80％，在大多数欧洲，案件的死亡率似乎至少降低了90％。这些比实证研究中报道的更大，更快的变化，例如从3月至2020年8月，纽约市医院系统的死亡率降低了18％（Horwitz等人，Covid-19的Covid-19风险调节死亡率的趋势，J。Hosp。Med。2020）。我们报道的减少令人惊讶地与其他模型参数（例如接触率）或其他标准状态/国家指标（例如人口密度，GDP和中位年龄）没有很强的相关性。几乎所有的减少都发生在4月中旬和6月中旬之间，这意外地与许多州和国家锁定释放的时间相对应，从而导致新案件的激增。检查了该下降的几种合理原因，例如改善治疗，口罩戴，新病毒菌株以及可能变化的受感染患者的人口统计数据，但鉴于当前可用的证据，没有人令人信服。
By fitting a compartment ODE model for Covid-19 propagation to cumulative case and death data for US states and European countries, we find that the case mortality rate seems to have decreased by at least 80% in most of the US and at least 90% in most of Europe. These are much larger and faster changes than reported in empirical studies, such as the 18% decrease in mortality found for the New York City hospital system from March to August 2020 (Horwitz et al, Trends in Covid-19 risk-adjusted mortality rates, J. Hosp. Med. 2020). Our reported decreases surprisingly do not have strong correlations to other model parameters (such as contact rate) or other standard state/national metrics such as population density, GDP, and median age. Almost all the decreases occurred between mid-April and mid-June, which unexpectedly corresponds to the time when many state and national lockdowns were released resulting in surges of new cases. Several plausible causes for this drop are examined, such as improvements in treatment, face mask wearing, a new virus strain, and potentially changing demographics of infected patients, but none are overwhelmingly convincing given the currently available evidence.
