Second wave Average monthly reported coronavirus deaths per 100,000 U.S. residents Initial period Third wave/ Spring/ vaccine rollout summer 2021 3/15/20- 7/1/20- 10/1/20- 4/1/21- 6/30/20 9/30/20 3/31/21 7/31/21 Total 11 8 18 5 By decile, the 10% of Americans living in the ... Most densely populated counties Least densely populated counties Fourth wave Fifth wave (delta variant (omicron surge) surge) 8/1/21- 11/30/21 12/1/21- 2/28/22 12 16 0 10 20 30 10 20 10 20 10 20 10 20 0 10 20 Note: Counties are grouped into deciles by population density. Each decile represents 10% of the total U.S. population. Source: Pew Research Center analysis of COVID-19 data collected by The New York Times as of Feb. 28 2022 See methodology for details