アメリカでは、非薬物介入とワクチン接種を併用することで推定約 215万件の COVID-19 関連死を防ぎ、完全な介入によりさらに 70万件以上の死者数を回避できた

Background Non-pharmaceutical interventions (NPIs) for control of COVID include a range of methods from masks to closures of schools and businesses with the efficacy of any individual strategy contingent on which other NPIs are employed and the extent of compliance with those strategies. In the case of a public health intervention, one typically looks at historical data for comparison, but, because COVID is a new disease, we have no such data. However, we do have extensive historical data for influenza, a respiratory disease with similar modes of transmission. Influenza incidence and mortality dropped dramatically during the COVID pandemic, almost certainly because of these NPIs. The extent of that drop provides an indirect measure of the efficacy of COVID NPIs in stopping the transmission of respiratory infections. This study evaluates the association of influenza mortality reduction (IMR) during the pandemic with age-adjusted COVID mortality among US states, adjusting for mortality prior to the introduction of NPIs and vaccination rates, while taking into account the impact of population density on NPI effectiveness. Results A simple linear model with pre-intervention COVID mortality, IMR, vaccination rate, and population density explained 70% of the state-to-state variability in age adjusted COVID mortality. The resulting model suggests that NPIs prevented 831,000 COVID related deaths in the United States over the course of the pandemic. Conclusions These results provide strong evidence that IMR is an accurate indicator of the efficacy of NPIs in controlling transmission of respiratory infections, including COVID. This analysis suggests that NPIs together with vaccination prevented an estimated 2.15 million COVID related deaths and full intervention could have prevented over 700,000 more. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All data were openly available before the initiation of the study from the CDC and the census bureau as listed below. 1. CDC (2023). Weekly U.S. Influenza Surveillance Report. Cent. Dis. Control Prev. . 2. CDC (2020). COVID Data Tracker. Cent. Dis. Control Prev. . 3.Provisional COVID-19 Deaths by Sex and Age | Data | Centers for Disease Control and Prevention . 4.US Census Bureau (1910). Population Density of the 50 States, the District of Columbia, and Puerto Rico: 1910 to 2020. N. Y. . I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the author. All data used in the current work are included in the manuscript.