Abstract
This study compares the COVID-19 per capita overall and excess mortality rates in the US vs rates for 20 Organization for Economic Co-operation and Development countries and the timing of any increases in excess mortality between June 2021 and December 2021 (Delta) and December 2021 to March 2022 (Omicron).
The US experienced high COVID-19 death rates and higher excess all-cause mortality compared with peer countries during 2020.1 However, an important question is how cross-national differences in mortality shifted during 2021 and 2022 with both widespread availability of vaccination and new variants. We compared COVID-19 and excess all-cause mortality in the US, the 10 most- and least-vaccinated states, and 20 peer Organization for Economic Co-operation and Development (OECD) countries during the Delta and winter Omicron waves.
Methods
Using previous methodology, we compared the US overall, the 10 most- and least-vaccinated states, and the 20 OECD countries with 2021 population exceeding 5 million and greater than $25 000 per capita gross domestic product (Supplement 1).1 US COVID-19 mortality, all-cause mortality, and vaccination data were obtained from the US Centers for Disease Control and Prevention.2 For other countries, COVID-19 mortality data were obtained from the World Health Organization, all-cause mortality data from OECD databases, and vaccination data from Our World in Data (Supplement 1).3,4,5 Some mortality data from 2021 and 2022 were provisional.
Each location’s COVID-19 mortality rate per capita was calculated over 2 periods: (1) Delta from June 27, 2021 (week 26), to December 25, 2021 (week 51), and (2) Omicron from December 26, 2021 (week 52), to March 26, 2022 (week 12). We estimated excess all-cause mortality by comparing mortality in each period with mortality in 2015-2019, fitting underlying trends using prepandemic, out-of-sample validation (Supplement 1).6
For each period, we calculated the difference in US deaths if mortality rates of other locations were realized. We used regression models to statistically compare rates across locations (Supplement 1), with significance set at P < .005 for 2-sided tests to account for multiple testing. Analyses were conducted in R version 4.0.2 (R Foundation for Statistical Computing). The study was deemed not human subjects research by the Brown University institutional review board.
Results
The US reported 370 298 COVID-19 deaths (112 per 100 000) during the Delta and Omicron waves (61/100 000 and 51/100 000, respectively). COVID-19 deaths per capita in the US overall and in both state subgroups significantly exceeded those of all peer countries during the study period (Table 1). However, there were significantly fewer COVID-19 deaths in the top 10 states by vaccination uptake (73% coverage) at 75 deaths/100 000 compared with the bottom 10 (52% coverage) at 146 per 100 000 (P < .001).
Table 1. COVID-19 Mortality in the US and Comparison Countries.
| Country | Vaccination rate, % | COVID-19 mortality per 100 000 | Potential US deaths averted, No. (%) | ||||
|---|---|---|---|---|---|---|---|
| Delta | Omicron | Total | Delta | Omicron | Total | ||
| New Zealand | 75 | 0.5 | 3.3 | 3.7 | 200 663 (99) | 157 236 (94) | 357 899 (97) |
| Japan | 80 | 3 | 7.4 | 10.4 | 192 278 (95) | 143 443 (85) | 335 721 (91) |
| Australia | 76 | 4.9 | 14.2 | 19.2 | 185 819 (92) | 120 894 (72) | 306 713 (83) |
| Republic of Korea | 82 | 6.1 | 18.2 | 24.3 | 181 927 (90) | 107 650 (64) | 289 577 (78) |
| The Netherlands | 67 | 16.6 | 7.9 | 24.5 | 147 061 (73) | 141 898 (84) | 288 959 (78) |
| Norway | 73 | 10 | 18.6 | 28.7 | 168 899 (84) | 106 280 (63) | 275 179 (74) |
| Canada | 77 | 10.2 | 20.2 | 30.4 | 168 351 (83) | 101 049 (60) | 269 401 (73) |
| Switzerland | 67 | 16.4 | 15.5 | 31.9 | 147 757 (73) | 116 511 (69) | 264 268 (71) |
| Sweden | 70 | 6.3 | 31.3 | 37.6 | 181 286 (90) | 64 167 (38) | 245 453 (66) |
| Ireland | 78 | 20.5 | 17.2 | 37.7 | 134 206 (66) | 110 857 (66) | 245 063 (66) |
| France | 74 | 14.6 | 27.6 | 42.2 | 153 765 (76) | 76 453 (45) | 230 218 (62) |
| Israel | 64 | 19.4 | 24.9 | 44.3 | 137 898 (68) | 85 326 (51) | 223 224 (60) |
| Spain | 80 | 17.7 | 26.7 | 44.5 | 143 348 (71) | 79 372 (47) | 222 720 (60) |
| Finland | 74 | 12 | 35.2 | 47.2 | 162 449 (80) | 51 097 (30) | 213 546 (58) |
| Belgium | 76 | 25.3 | 22.5 | 47.7 | 118 390 (59) | 93 526 (56) | 211 916 (57) |
| Denmark | 78 | 10.9 | 41.2 | 52.2 | 166 026 (82) | 31 182 (19) | 197 208 (53) |
| Germany | 71 | 29.6 | 22.7 | 52.3 | 104 041 (51) | 92 750 (55) | 196 792 (53) |
| Italy | 76 | 15.2 | 39 | 54.2 | 151 867 (75) | 38 609 (23) | 190 476 (51) |
| UK | 71 | 30.1 | 28.9 | 59 | 102 324 (51) | 72 176 (43) | 174 500 (47) |
| Austria | 74 | 40.4 | 24.6 | 65 | 68 040 (34) | 86 582 (52) | 154 622 (42) |
| US | |||||||
| 10 most-vaccinated states | 73 | 28.1 | 46.6 | 74.7 | 108 916 (54) | 13 388 (8) | 122 304 (33) |
| Overall | 63 | 60.9 | 50.6 | 111.6 | |||
| 10 least-vaccinated states | 52 | 86.6 | 59.4 | 146 | −85 080 (−42) | −29 058 (−17) | −114 138 (−31) |
Countries are ordered by total COVID-19 mortality rate from June 27, 2021-March 26, 2022. This includes the Delta (June 27, 2021-December 25, 2021) and winter Omicron (December 26, 2021-March 26, 2022) periods. Vaccination rates reflect the population percentage with 2 or more doses as of January 2022. States include the 50 states and District of Columbia. Potential deaths averted were calculated assuming that the full US had the per capita COVID-19 mortality rate of the specified country/states during the period of interest. All comparisons between the US and other countries were statistically significant in all periods, as were comparisons between the 10 most-vaccinated and 10 least-vaccinated states and comparisons between state subgroups and other countries (P < .001).
US excess all-cause mortality exceeded COVID-19 mortality at 145/100 000 and exceeded peer countries in all periods, as did excess all-cause mortality in the least-vaccinated states (Table 2). However, the 10 most-vaccinated states had excess all-cause mortality comparable with or less than that of several peer countries over Delta and Omicron combined (eg, Denmark, Germany, the Netherlands, Austria, Italy, Finland). While excess all-cause mortality in the top 10 states significantly exceeded that of many comparators during Omicron, excess all-cause mortality was significantly less than COVID-19 mortality for the top 10 states during this wave (29 vs 47 per 100 000, P < .001).
Table 2. Excess All-Cause Mortality in the US and Comparison Countries.
| Country | Vaccination rate, % | Excess all-cause mortality per 100 000 | Potential US deaths averted, No. (%) | ||||
|---|---|---|---|---|---|---|---|
| Delta | Omicron | Total | Delta | Omicron | Total | ||
| New Zealand | 75 | −7.6 | 12.7 | 5.1 | 354 910 (108) | 110 837 (72) | 465 747 (96) |
| Sweden | 70 | 20.8 | 11.6 | 32.4 | 260 705 (79) | 114 455 (75) | 375 159 (78) |
| Belgium | 76 | 36.1 | −2.2 | 33.9 | 209 740 (64) | 160 481 (105) | 370 221 (77) |
| France | 74 | 26.4 | 10.8 | 37.2 | 241 932 (73) | 117 271 (77) | 359 203 (74) |
| Canada | 77 | 24.5 | 13 | 37.5 | 248 446 (75) | 109 860 (72) | 358 306 (74) |
| Australia | 76 | 9.6 | 28.6 | 38.1 | 297 871 (90) | 58 315 (38) | 356 186 (74) |
| Switzerland | 67 | 35.3 | 3.8 | 39.1 | 212 401 (64) | 140 586 (92) | 352 987 (73) |
| Spain | 80 | 39.2 | 3.3 | 42.5 | 199 500 (61) | 142 251 (93) | 341 752 (71) |
| UK | 71 | 53.2 | −4.2 | 49 | 153 074 (46) | 167 074 (109) | 320 148 (66) |
| Israel | 64 | 29.7 | 27.8 | 57.4 | 231 156 (70) | 60 978 (40) | 292 134 (61) |
| Norway | 73 | 45.7 | 12.4 | 58.1 | 177 988 (54) | 111 819 (73) | 289 807 (60) |
| Denmark | 78 | 45.7 | 14.3 | 60 | 178 016 (54) | 105 494 (69) | 283 510 (59) |
| Germany | 71 | 62.8 | 0.2 | 63.1 | 121 191 (37) | 152 333 (99) | 273 524 (57) |
| The Netherlands | 67 | 65.4 | −1.8 | 63.6 | 112 691 (34) | 159 037 (104) | 271 728 (56) |
| 10 most-vaccinated US states | 73 | 36.4 | 28.7 | 65.1 | 208 703 (63) | 57 997 (38) | 266 700 (55) |
| Italy | 76 | 50.3 | 20.9 | 71.2 | 162 666 (49) | 83 790 (55) | 246 456 (51) |
| Austria | 74 | 65.4 | 7.5 | 72.9 | 112 625 (34) | 128 245 (84) | 240 871 (50) |
| Finland | 74 | 54.6 | 27.6 | 82.2 | 148 495 (45) | 61 429 (40) | 209 924 (43) |
| US overall | 63 | 99.3 | 46.1 | 145.5 | |||
| 10 least-vaccinated US states | 52 | 136 | 57.3 | 193.3 | −121 749 (−37) | −37 173 (−24) | −158 922 (−33) |
Countries are ordered by total excess all-cause mortality rate from June 27, 2021-March 26, 2022. This includes the Delta (June 27, 2021-December 25, 2021) and winter Omicron periods (December 26, 2021-March 26, 2022) periods. Vaccination rates reflect the population percentage with 2 or more doses as of January 2022. States include the 50 states and District of Columbia. Potential deaths averted were calculated assuming that the full US had the all-cause mortality rate of the specified country/states during the period of interest. All comparisons between the US overall and other countries were statistically significant in all periods (P < .005), as were comparisons between the 10 most-vaccinated and least-vaccinated states and comparisons between the 10 least-vaccinated states and all other countries (P < .001).
From June 27, 2021, to March 26, 2022, the US would have averted 122 304 deaths if COVID-19 mortality matched that of the 10 most-vaccinated states and 266 700 deaths if US excess all-cause mortality rate matched that of the 10 most-vaccinated states. If the US matched the rates of other peer countries, averted deaths would have been substantially higher in most cases (range, 154 622-357 899 for COVID-19 mortality; 209 924-465 747 for all-cause mortality).
Discussion
The US continued to experience significantly higher COVID-19 and excess all-cause mortality compared with peer countries during 2021 and early 2022, a difference accounting for 150 000 to 470 000 deaths. This difference was muted in the 10 states with highest vaccination coverage; remaining gaps may be explained by greater vaccination uptake in peer countries, better vaccination targeting to older age groups, and differences in health and social infrastructure.
This study also highlights the value of excess mortality in understanding effects of COVID-19. Excess all-cause mortality began to fall below COVID-19 mortality in several countries and highly vaccinated states during Omicron, perhaps owing to reductions in non–COVID-19 deaths. However, cross-location differences may also reflect differences in COVID-19 death coding.
Limitations include use of some provisional mortality estimates and lack of adjustment by age and comorbidities. Nevertheless, unadjusted estimates remain important, because a country’s response to COVID-19 should reflect risks in its population rather than a hypothetical standardized population.
These findings highlight that the US continued to lag peer countries in COVID-19 and excess all-cause mortality, albeit with lower mortality in highly vaccinated states.
Section Editors: Jody W. Zylke, MD, Deputy Editor; Kristin Walter, MD, Senior Editor.
Data Sources
Calculations in Tables 1 and 2
States by Vaccination Rate
Excess Mortality Model Selection (Table 2)
Statistical Analyses
Data Sharing Statement
References
- 1.Bilinski A, Emanuel EJ. COVID-19 and excess all-cause mortality in the US and 18 comparison countries. JAMA. 2020;324(20):2100-2102. doi: 10.1001/jama.2020.20717 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Excess Deaths Associated With COVID-19 . Accessed May 12, 2022. https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm
- 3.WHO coronavirus (COVID-19) dashboard with vaccination data. World Health Organization. Accessed October 11, 2022. http://covid19.who.int/data/
- 4.COVID-19 health indicators: mortality (by week). Organisation for Economic Cooperation and Development. Accessed May 12, 2022. https://stats.oecd.org/Index.aspx?DataSetCode=HEALTH_MORTALITY
- 5.Ritchie H, Mathieu E, Rodés-Guirao L, et al. Coronavirus (COVID-19) vaccinations. Our World in Data. Accessed October 11, 2022. https://ourworldindata.org/covid-vaccinations
- 6.Ruhm CJ. Excess deaths in the United States during the first year of COVID-19: NBER Working Paper 29503. National Bureau of Economic Research. Published November 2021. Accessed November 11, 2022. http://www.nber.org/papers/w29503
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Sources
Calculations in Tables 1 and 2
States by Vaccination Rate
Excess Mortality Model Selection (Table 2)
Statistical Analyses
Data Sharing Statement