What a Standard Candle Reveals: Inequity in COVID Outcomes

F. Perry Wilson, MD, MSCE


October 06, 2021

This transcript has been edited for clarity.

Welcome to Impact Factor, your weekly dose of commentary on a new medical study. I'm Dr F. Perry Wilson of the Yale School of Medicine.

The COVID pandemic has shone a light on so many aspects of our culture, from our woefully inadequate public health infrastructure to the way that political ideologies can shape interpretations of data. One factor that makes COVID a useful lens to pick out the inequities in our society is that it is basically a standard candle.

The idea of the standard candle comes to us from physics — knowing how bright a given astronomical object should be compared with its measured brightness lets us tell how far away it is. COVID is like that in a way. Biologically, COVID is just as capable of infecting and killing the rich and the poor, Black and White. And yet, throughout the pandemic, outcomes among certain groups — minorities, the poor, those without good access to care — have been dramatically worse.

And now, thanks to a paper appearing in Annals of Internal Medicine, we can finally put some real numbers to the burden these communities have faced during the pandemic, using another standard candle: the excess death rate.

The raw number of COVID cases is biased by testing rates; we know we're missing a bunch of cases. Deaths due to COVID are a more reliable indicator of the severity of the pandemic, but there is a vocal minority of individuals who question the number of deaths attributed to COVID. But excess deaths is a tough number to argue with. The idea is that you look at the population-wide death rate in prior years to see how many unexpected, extra deaths occurred during the pandemic.

The data here really speaks for itself. In 2019, 2.9 million Americans died. In 2020, 3.4 million died. That's 18% higher. Eighteen percent more Americans died in 2020 compared with 2019. This is nowhere near a normal variance. I looked at the data for the past 10 years or so, and the yearly death rate typically varies by a percentage point or two from year to year.


It's fairly clear that the vast majority of these excess deaths were due to COVID. Using death certificate data, the researchers attribute 74% of the excess deaths to the virus.


But there are excess deaths even beyond that — predominantly attributed to heart disease and diabetes. It's interesting to note that cancer deaths were lower than expected in 2020, though that may likely be due to decreases in detection as screening programs were sidelined by the virus.


Shiels MS, et al. Racial and ethnic disparities in excess deaths during the COVID-19 pandemic, March to December 2020, Ann Intern Med. 5 October 2021. [Epub ahead of print].

These excess deaths, COVID and non-COVID, are not distributed evenly. The brunt of excess mortality is clearly borne by minority populations, particularly Black, Latino, and Native populations.


Shiels MS, et al. Racial and ethnic disparities in excess deaths during the COVID-19 pandemic, March to December 2020, Ann Intern Med. 5 October 2021. [Epub ahead of print].

There has been a disparity in life expectancy between Black and White individuals in this country for as long as the data have been collected, but this disparity grew in 2020. Black men had a 25% higher mortality than White men in 2019; it was 45% higher in 2020. Black women had a 15% higher mortality rate in 2019; it was 32% higher in 2020.

This is a lesson we have learned several times in different forms, but I think it is most stark here. When the system is stressed, those who are already marginalized suffer the most. Poor access to healthcare matters more when there is a pandemic. The high cost of prescription drugs matters more when there is a pandemic. The lack of access to quality mental healthcare matters more when there is a pandemic.

COVID is a tragedy for the entire world, regardless of race or class, station or religion. But these are things that, biologically, the virus doesn't see. The fact that there are disparities in outcomes is a reflection on us — our institutions, our choices. Let's learn from this to start actually changing those things so that we can minimize the impact of the next standard candle that comes along.

F. Perry Wilson, MD, MSCE, is an associate professor of medicine and director of Yale's Clinical and Translational Research Accelerator. His science communication work can be found in the Huffington Post, on NPR, and here on Medscape. He tweets @fperrywilson and hosts a repository of his communication work at

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