Modeling of Future COVID-19 Cases, Hospitalizations, and Deaths, by Vaccination Rates and Nonpharmaceutical Intervention Scenarios — United States, April–September 2021
Rebecca K. Borchering, Cécile Viboud, Emily Howerton, Claire P. Smith, Shaun Truelove, Michael C. Runge, Nicholas G Reich, Lucie Contamin, John Levander, Jessica Salerno, Wilbert van Panhuis, Matt Kinsey, Kate Tallaksen, Richard Obrecht, Laura Asher, Cash Costello, Michael Kelbaugh, Shelby Wilson, Lauren Shin, Molly Gallagher, Luke C. Mullany, Kaitlin Rainwater‐Lovett, Joseph C. Lemaitre, Juan Dent, Kyra H. Grantz, Joshua Kaminsky, Stephen A. Lauer, Elizabeth C. Lee, Hannah R. Meredith, Javier Perez‐Saez, Lindsay T. Keegan, D. Karlen, Matteo Chinazzi, Jessica T. Davis, Kunpeng Mu, Xinyue Xiong, Ana Pastore y Piontti, Alessandro Vespignani, Ajitesh Srivastava, Przemyslaw Porebski, Srinivasan Venkatramanan, Aniruddha Adiga, Bryan Lewis, Brian Klahn, Joseph Outten, James Schlitt, Patrick Corbett, Pyrros A. Telionis, Lijing Wang, Akhil Sai Peddireddy, Benjamin Hurt, Jiangzhuo Chen, Anil Vullikanti, Madhav Marathe, Jessica M. Healy, Rachel B. Slayton, Matthew Biggerstaff, Michael A. Johansson, Katriona Shea, Justin Lessler
Abstract
After a period of rapidly declining U.S. COVID-19 incidence during January-March 2021, increases occurred in several jurisdictions (1,2) despite the rapid rollout of a large-scale vaccination program. This increase coincided with the spread of more transmissible variants of SARS-CoV-2, the virus that causes COVID-19, including B.1.1.7 (1,3) and relaxation of COVID-19 prevention strategies such as those for businesses, large-scale gatherings, and educational activities. To provide long-term projections of potential trends in COVID-19 cases, hospitalizations, and deaths, COVID-19 Scenario Modeling Hub teams used a multiple-model approach comprising six models to assess the potential course of COVID-19 in the United States across four scenarios with different vaccination coverage rates and effectiveness estimates and strength and implementation of nonpharmaceutical interventions (NPIs) (public health policies, such as physical distancing and masking) over a 6-month period (April-September 2021) using data available through March 27, 2021 (4). Among the four scenarios, an accelerated decline in NPI adherence (which encapsulates NPI mandates and population behavior) was shown to undermine vaccination-related gains over the subsequent 2-3 months and, in combination with increased transmissibility of new variants, could lead to surges in cases, hospitalizations, and deaths. A sharp decline in cases was projected by July 2021, with a faster decline in the high-vaccination scenarios. High vaccination rates and compliance with public health prevention measures are essential to control the COVID-19 pandemic and to prevent surges in hospitalizations and deaths in the coming months.