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Truelove, Shaun A.; Smith, Claire P.; Qin, Michelle; Mullany, Luke C.; Borchering, Rebecca K.; Lessler, Justin; Shea, Katriona; Howerton, Emily; Contamin, Lucie; & Levander, John, et al. (Preprint). Projected Resurgence of COVID-19 in the United States in July-December 2021 Resulting from the Increased Transmissibility of the Delta Variant and Faltering Vaccination. medRxiv. PMCID: PMC8423228


WHAT IS ALREADY KNOWN ABOUT THIS TOPIC? The highly transmissible SARS-CoV-2 Delta variant has begun to cause increases in cases, hospitalizations, and deaths in parts of the United States. With slowed vaccination uptake, this novel variant is expected to increase the risk of pandemic resurgence in the US in July-December 2021.
WHAT IS ADDED BY THIS REPORT? Data from nine mechanistic models project substantial resurgences of COVID-19 across the US resulting from the more transmissible Delta variant. These resurgences, which have now been observed in most states, were projected to occur across most of the US, coinciding with school and business reopening. Reaching higher vaccine coverage in July-December 2021 reduces the size and duration of the projected resurgence substantially. The expected impact of the outbreak is largely concentrated in a subset of states with lower vaccination coverage.
WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE? Renewed efforts to increase vaccination uptake are critical to limiting transmission and disease, particularly in states with lower current vaccination coverage. Reaching higher vaccination goals in the coming months can potentially avert 1.5 million cases and 21,000 deaths and improve the ability to safely resume social contacts, and educational and business activities. Continued or renewed non-pharmaceutical interventions, including masking, can also help limit transmission, particularly as schools and businesses reopen.


Reference Type

Journal Article

Year Published


Journal Title



Truelove, Shaun A.
Smith, Claire P.
Qin, Michelle
Mullany, Luke C.
Borchering, Rebecca K.
Lessler, Justin
Shea, Katriona
Howerton, Emily
Contamin, Lucie
Levander, John
Salerno, Jessica
Hochheiser, Harry
Kinsey, Matt
Tallaksen, Kate
Wilson, Shelby
Shin, Lauren
Rainwater-Lovett, Kaitlin
Lemaitre, Joseph C.
Dent, Juan
Kaminsky, Joshua
Lee, Elizabeth C.
Perez-Saez, Javier
Hill, Alison
Karlen, Dean
Chinazzi, Matteo
Davis, Jessica T.
Mu, Kunpeng
Xiong, Xinyue
Y Piontti, Ana Pastore
Vespignani, Alessandro
Srivastava, Ajitesh
Porebski, Przemyslaw
Venkatramanan, Srinivasan
Adiga, Aniruddha
Lewis, Bryan
Klahn, Brian
Outten, Joseph
Schlitt, James
Corbett, Patrick
Telionis, Pyrros Alexander
Wang, Lijing
Peddireddy, Akhil Sai
Hurt, Benjamin
Chen, Jiangzhuo
Vullikanti, Anil
Marathe, Madhav
Hoops, Stefan
Bhattacharya, Parantapa
Machi, Dustin
Chen, Shi
Paul, Rajib
Janies, Daniel
Thill, Jean-Claude
Galanti, Marta
Yamana, Teresa K.
Pei, Sen
Shaman, Jeffrey
Reich, Nicholas G.
Healy, Jessica M.
Slayton, Rachel B.
Biggerstaff, Matthew
Johansson, Michael A.
Runge, Michael C.
Viboud, C├ęcile

Article Type





United States of America


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