Skip to main content
American Journal of Public Health logoLink to American Journal of Public Health
. 2021 Oct;111(10):1847–1850. doi: 10.2105/AJPH.2021.306430

Excess Deaths in Mexico City and New York City During the COVID-19 Pandemic, March to August 2020

Martín Lajous 1,, Rodrigo Huerta-Gutiérrez 1, Joseph Kennedy 1, Donald R Olson 1, Daniel M Weinberger 1
PMCID: PMC8561207  PMID: 34499539

Abstract

Objectives. To estimate all-cause excess deaths in Mexico City (MXC) and New York City (NYC) during the COVID-19 pandemic.

Methods. We estimated expected deaths among residents of both cities between March 1 and August 29, 2020, using log-linked negative binomial regression and compared these deaths with observed deaths during the same period. We calculated total and age-specific excess deaths and 95% prediction intervals (PIs).

Results. There were 259 excess deaths per 100 000 (95% PI = 249, 269) in MXC and 311 (95% PI = 305, 318) in NYC during the study period. The number of excess deaths among individuals 25 to 44 years old was much higher in MXC (77 per 100 000; 95% PI = 69, 80) than in NYC (34 per 100 000; 95% PI = 30, 38). Corresponding estimates among adults 65 years or older were 1263 (95% PI = 1199, 1317) per 100 000 in MXC and 1581 (95% PI = 1549, 1621) per 100 000 in NYC.

Conclusions. Overall, excess mortality was higher in NYC than in MXC; however, the excess mortality rate among young adults was higher in MXC.

Public Health Implications. Excess all-cause mortality comparisons across populations and age groups may represent a more complete measure of pandemic effects and provide information on mitigation strategies and susceptibility factors. (Am J Public Health. 2021;111(10): 1847–1850. https://doi.org/10.2105/AJPH.2021.306430)


New York City (NYC; population: 8 398 748) and Mexico City (MXC; population: 9 041 395) are the largest North American cities. The first confirmed COVID-19–associated fatality in NYC occurred on March 11, 2020, and the first such fatality in MXC occurred a week later. Stay-at-home orders were put in place in both cities on March 22 and 23, 2020. Although age distributions, social determinants of health, and health care capacities differ, a direct comparison of excess deaths in the populations of these 2 cities can provide insights into the dynamics of disease spread as well as pandemic preparedness and response. NYC has an electronic rapid death surveillance system to address delays in reporting of vital statistics, and MXC implemented a similar system. Leveraging these rapid death surveillance systems, we estimated all-cause excess deaths in both cities from March to August 2020.

METHODS

For MXC, we obtained all-cause deaths occurring between January 1, 2017, and August 29, 2020, from https://datos.cdmx.gob.mx. A comparison between Mexico’s finalized 2017 vital statistics and MXC’s rapid death reporting system based on death certificates showed a difference of less than 1% (Table A, available as a supplement to the online version of this article at http://www.ajph.org). NYC all-cause deaths were obtained from the NYC Department of Health and Mental Hygiene (https://www1.nyc.gov/site/doh/providers/reporting-and-services/evital.page), which collects and reports deaths independently of New York State.

First, we estimated the baseline number of deaths among residents of both cities in the absence of COVID-19 by fitting a log-linked negative binomial regression model for weekly death counts from January 1, 2017, to February 29, 2020 (see the Appendix, available as a supplement to the online version of this article at http://www.ajph.org). Second, using this baseline, we projected expected deaths forward until August 29, 2020. Excess mortality was defined as the difference between the observed deaths in each week and the expected deaths in that week according to a baseline that was adjusted for seasonality and time trends. We estimated 95% prediction intervals (PIs) for the baseline and used them to calculate intervals for excess deaths. We also calculated excess deaths (and rates) for age groups (0–24, 25–44, 45–64, ≥ 65 years). We age standardized estimates using NYC’s age distribution and the world standard population (see the Appendix). We repeated our analyses including deaths among nonresidents.

RESULTS

Between March 1 and August 29, 2020, we found 259 excess deaths per 100 000 (95% PI = 249, 269) in MXC and 311 excess deaths per 100 000 (95% PI = 305, 318) in NYC relative to what would be expected at that time of year (Table C, available as a supplement to the online version of this article at http://www.ajph.org). When we age standardized excess deaths in MXC using NYC’s age distribution, there were 326 (95% PI = 317, 335) excess deaths per 100 000. Excess mortality peaked in NYC during the week ending on April 11, 2020 (7-fold increase over baseline), and a month later in MXC (2.5-fold increase over baseline; Figure 1). Excess deaths were not detected in NYC during July and August. In MXC, there were 2600 excess deaths in August.

FIGURE 1—

FIGURE 1—

Excess Deaths in New York City and Mexico City, 2020

Note. The observed numbers of deaths in Mexico City (red) and New York City (blue) are indicated by darker lines, and the expected numbers of deaths after adjustment for seasonality and variation between years are indicated by lighter lines. The area between the solid and dashed lines represents the total number of excess deaths.

Excess death age patterns differed between cities. Among individuals 25 to 45 years old, the excess mortality rate was 126% higher in MXC (77 per 100 000; 95% PI = 69, 80) than in NYC (34 per 100 000; 95% PI = 30, 38). Similarly, among individuals 45 to 64 years of age, excess mortality was 77% higher in MXC (467 per 100 000; 95% PI = 453, 482) than in NYC (263 per 100 000; 95% PI = 253, 272; Figure A, available as a supplement to the online version of this article at http://www.ajph.org). Among adults 65 years or older, excess death rates were 1263 per 100 000 (95% PI = 1199, 1317) in MXC and 1581 per 100 000 (95% PI = 1549, 1621) in NYC (Table C). Excess mortality appeared to be lagged by a month in MXC relative to NYC among those 65 years or older, and 75% of excess deaths in NYC occurred among adults in this age group, compared with 50% of excess deaths in MXC. Overall, MXC saw 7600 excess deaths among nonresidents, whereas NYC had only 500 (Figure B, available as a supplement to the online version of this article at http://www.ajph.org).

DISCUSSION

We observed a higher excess mortality rate in NYC than in MXC. Excess deaths peaked and dropped rapidly in NYC. The rise was less pronounced in MXC, but excess deaths were still occurring in August 2020. We observed higher rates of excess death in MXC among young adults.

Several factors may explain the higher overall rates of excess death observed in NYC relative to MXC. First, older individuals are at a higher risk of COVID-19 severity. Although the percentage of the population 45 to 64 years of age is similar in the 2 cities, the percentage of people 65 years or older is higher in NYC than in MXC (15% vs 10%). Second, the spring wave of COVID-19 cases in NYC led to a significant surge in health care demand that, coupled with uncertainties about transmission and infectiousness as well as the severity of this novel coronavirus, may have resulted in avoidance of care. Individuals with acute conditions requiring immediate care (e.g., stroke) may have been reluctant to activate emergency services or visit a hospital for fear of SARS-CoV-2 exposure.1

Third, the dramatic epidemic wave in NYC, which was not seen in MXC, may be explained in part by higher population density (10 716 residents/km2 in NYC vs 6202 in MXC)2 and the rapid spread of SARS-CoV-2 in long-term care facilities.3 Nursing homes for older adults are more common in NYC, whereas most older adults in Mexico live with their families.4 Finally, the timing of stay-at-home directives in MXC may have been early enough to mitigate widespread community transmission before a rapid increase, particularly among the elderly. Even though SARS-CoV-2 testing was mostly limited to hospitalized patients in MXC, there were 868 laboratory-confirmed COVID-19 cases by April 7, whereas NYC had recorded 76 876.5,6

The 1918 influenza pandemic autumn wave also resulted in somewhat higher excess respiratory mortality in NYC relative to MXC (518 vs 470 deaths per 100 000).7,8 However, in contrast to NYC and other cities, older adults in MXC were not spared. Obesity and obesity-related chronic conditions predict greater COVID-19 severity.9 The unexpectedly high excess mortality among younger adults in MXC may reflect Mexico’s obesity epidemic (38.9% of individuals 25–44 years of age in MXC are obese, compared with 24.1% in NYC) and the increasing prevalence of diabetes in this age group.10,11 Differences in the distribution of susceptibility factors may explain age patterns in excess mortality during pandemics.

In MXC, although SARS-CoV-2 test positivity and COVID-19 hospitalizations were dropping in August and had stabilized, excess deaths were not contained.6 Community spread in MXC may have continued during stay-at-home orders because adherence may have been challenging for households dependent on informal employment. Also, MXC converted 52 hospitals to COVID-19-only facilities. Although this measure increased access to COVID-19 care (and averted virus-related deaths), displacement of care for other conditions (e.g., cancer) may have resulted in non-COVID-19 deaths.

Excess deaths reflect increased mortality due to the virus as well as increases (and declines) in other causes. Although initial estimates show that 66% of excess deaths in MXC6 and 78% in NYC were attributable to COVID-19 during this period,12 we were limited by our use of surveillance systems rather than finalized official vital statistics in which causes of death are accurately coded. Our analysis was also limited because data on influenza epidemics to adjust baseline deaths in MXC and on nonresident population estimates to calculate excess death rates were unavailable. Also, we did not have information on the number of residents who left and died outside the 2 cities and the number who moved in and subsequently died. These issues will likely be best understood once the pandemic has ended.

PUBLIC HEALTH IMPLICATIONS

Comparisons of excess all-cause mortality across populations and age groups may allow a more complete assessment of pandemic effects and provide important information on mitigation strategies and susceptibility factors. Timely mortality surveillance systems, an essential component of pandemic preparedness, can be effectively implemented as part of the pandemic response.

ACKNOWLEDGMENTS

We acknowledge the New York City Department of Health and Mental Hygiene, Bureau of Vital Statistics team, and members of the Incident Command System Surveillance and Epidemiology Section. We also acknowledge Marion Bochier of Instituto Nacional de Salud Pública, who provided obesity prevalence estimates for Mexico City.

CONFLICTS OF INTEREST

M. Lajous received a nonrestricted investigator-initiated grant for cardiovascular health research from AstraZeneca that ended in 2017. M. Lajous is the institutional representative for collaborative agreements between Instituto Nacional de Salud Pública and Mexico City’s Agencia Digital de Innovación Pública and Secretaria de Salud for work unrelated to this article. D. M. Weinberger has received consulting fees from Pfizer, Merck, GSK, and Affinivax for work unrelated to this article, and he is a principal investigator on research grants from Pfizer and Merck to Yale University for work unrelated to this article.

HUMAN PARTICIPANT PROTECTION

No protocol approval was needed for this study because de-identified, publicly available data were used.

REFERENCES

  • 1. Sharma M, Lioutas VA, Madsen T, et al. Decline in stroke alerts and hospitalisations during the COVID-19 pandemic. Stroke Vasc Neurol. . 2020;5(4):403–405. doi: 10.1136/svn-2020-000441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Brinkhoff T.http://www.citypopulation.de
  • 3. McMichael TM, Clark S, Pogosjans S, et al. COVID-19 in a long-term care facility—King County, Washington, February 27–March 9, 2020. MMWR Morb Mortal Wkly Rep. . 2020;69(12):339–342. doi: 10.15585/mmwr.mm6912e1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Sanchez Peña L, Escoto Castillo A.Arreglos residenciales multigeneracionales y pobreza en México Coyuntura Demográfica. 20171271–77.. [Google Scholar]
  • 5. Centers for Disease Control and Prevention. Geographic differences in COVID-19 cases, deaths, and incidence—United States, February 12–April 7, 2020. MMWR Morb Mortal Wkly Rep. . 2020;69(15):465–471. doi: 10.15585/mmwr.mm6915e4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Government of Mexico City. https://covid19.cdmx.gob.mx
  • 7. Olson DR, Simonsen L, Edelson PJ, Morse SS. Epidemiological evidence of an early wave of the 1918 influenza pandemic in New York City. Proc Natl Acad Sci U S A. . 2005;102(31):11059–11063. doi: 10.1073/pnas.0408290102. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8. Chowell G, Viboud C, Simonsen L, Miller MA, Acuna-Soto R. Mortality patterns associated with the 1918 influenza pandemic in Mexico: evidence for a spring herald wave and lack of preexisting immunity in older populations. J Infect Dis. . 2010;202(4):567–575. doi: 10.1086/654897. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9. Richardson S, Hirsch JS, Narasimhan M, et al. Presenting characteristics, comorbidities, and outcomes among 5700 patients hospitalized with COVID-19 in the New York City area. JAMA. . 2020;323(20):2052–2059. doi: 10.1001/jama.2020.6775. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Shamah-Levy T, Vielma-Orozco E, Heredia-Hernandez O, et al. Encuesta Nacional de Salud y Nutricion 2018–19: Resultados Nacionales. Cuernavaca, Mexico: Instituto Nacional de Salud Publica; 2020. [Google Scholar]
  • 11.Behavioral Risk Factor Surveillance System Survey Data. Atlanta, GA: Centers for Disease Control and Prevention; 2016. [Google Scholar]
  • 12.New York City Department of Health and Mental Hygiene COVID-19 Response Team Preliminary estimate of excess mortality during the COVID-19 outbreak—New York City, March 11–May 2, 2020 MMWR Morb Mortal Wkly Rep. 20206919603–605.. [DOI] [PubMed] [Google Scholar]

Articles from American Journal of Public Health are provided here courtesy of American Public Health Association

RESOURCES