There remains no approved vaccine for the prevention of SARS-CoV-2 infection, and few pharmaceutical options for the treatment of COVID-19 are available 9, 10, 11. 7 first death on 6 February 2020: ), SARS-CoV-2 has spread to every state and has resulted in more than 28.2 million cases and 199,213 deaths as of 21 September 2020 ( ) 7, 8. Since the first case in the United States was identified on 20 January 2020 (ref. The establishment of SARS-CoV-2 and its rapid spread in the United States has been dramatic ( ). This pandemic has already resulted in extreme societal, economic and political disruption across the world and in the United States ( ) 5, 6.

The zoonotic origin of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 1 first reported in Wuhan, China 2, and the global spread of the coronavirus disease 2019 (COVID-19 ) 3 promises to be a defining global health event of the twenty-first century 4.

Universal mask use could save an additional 129,574 (85,284–170,867) lives from Septemthrough the end of February 2021, or an additional 95,814 (60,731–133,077) lives assuming a lesser adoption of mask wearing (85%), when compared to the reference scenario. We find that achieving universal mask use (95% mask use in public) could be sufficient to ameliorate the worst effects of epidemic resurgences in many states. Projections of current non-pharmaceutical intervention strategies by state-with social distancing mandates reinstated when a threshold of 8 deaths per million population is exceeded (reference scenario)-suggest that, cumulatively, 511,373 (469,578–578,347) lives could be lost to COVID-19 across the United States by 28 February 2021.

Using this SEIR model, and projections of critical driving covariates (pneumonia seasonality, mobility, testing rates and mask use per capita), we assessed scenarios of social distancing mandates and levels of mask use. We use COVID-19 case and mortality data from 1 February 2020 to 21 September 2020 and a deterministic SEIR (susceptible, exposed, infectious and recovered) compartmental framework to model possible trajectories of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the effects of non-pharmaceutical interventions in the United States at the state level from 22 September 2020 through 28 February 2021.

United by K.M. Shea