id author title date pages extension mime words sentences flesch summary cache txt cord-274264-s477tw3x Shen, M. Projected COVID-19 epidemic in the United States in the context of the effectiveness of a potential vaccine and implications for social distancing and face mask use 2020-10-30 .txt text/plain 4120 221 54 We evaluated the vaccine effectiveness and coverage required to suppress the COVID-19 epidemic in scenarios when social contact was to return to pre-pandemic levels and face mask use was reduced. But relaxing social distancing restrictions to the pre-pandemic level without changing the current face mask use would lead to a new COVID-19 outbreak, resulting in 0.8-4 million infections and 15,000-240,000 deaths across these four states over the next 12 months. In the state of California, if the current face mask use rate was maintained and the vaccine was weak, 50% coverage could avert 1 CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. However, the state of California, in particular, will need a vaccine coverage of close to 80% to suppress the COVID-19 epidemic, such that both social distancing restrictions and the requirement for face mask use can be relaxed. ./cache/cord-274264-s477tw3x.txt ./txt/cord-274264-s477tw3x.txt