California may have missed roughly 11,600 Covid deaths in 2020 and 2021, according to a major new analysis that suggests the country as a whole undercounted more than 150,000 fatalities. If the numbers hold, the study effectively pushes the United States death toll for the first two pandemic years to the edge of one million, well beyond what officials recorded at the time. The findings point to widespread testing gaps and large numbers of people dying outside hospitals in the early waves.
The study, published in Science Advances, estimates a true U.S. Covid death toll of about 995,787 for 2020 and 2021, compared with 840,251 deaths on the official books, which works out to roughly one missed death for every five counted. In California, researchers estimate about 11,613 Covid deaths were never formally recognized, and they say more than 111,000 of the missed deaths nationwide occurred at home where testing was inconsistent, as reported by the San Francisco Chronicle. The paper’s authors include Stanford epidemiologist Mathew Kiang and UCSF physician Kirsten Bibbins-Domingo.
How Researchers Found The Gap
To uncover the missing deaths, the team trained a machine learning algorithm using hospital death records, where Covid testing was most routine, then turned it loose on death certificates from outside hospital settings, according to Scientific American. The model flagged certificates that looked statistically similar to confirmed Covid deaths but had been coded under other causes, such as heart disease or dementia, suggesting an undiagnosed Covid infection. The result is a more fine grained look at undercounting than broader excess death estimates that simply compare total deaths with pre pandemic norms.
Who Bore The Brunt
The missing deaths were not spread evenly across the population. Undercounting was more common for people identified on death certificates as Hispanic, Black, Asian, American Indian and Alaska Native, and for those with lower education and income levels, the San Francisco Chronicle reports. Those patterns showed up at the county level and suggest that communities hit hardest by Covid were also the most likely to have their losses obscured in official statistics. Local public health workers and families had been warning about those blind spots in real time, particularly when tests and hospital care were hardest to obtain.
Why The Undercount Matters
“This underreporting that we found wasn’t random,” Mathew Kiang told Scientific American, pointing to structural barriers that left vulnerable people more likely to die outside the health system and outside the official tally. The authors acknowledge their model cannot prove that every flagged case was truly Covid 19, but they argue the scale and pattern of the findings point to systemic weaknesses in how deaths are recorded. Public health experts say that improving access to testing and modernizing vital records systems will be crucial to avoid repeating the same mistakes in future outbreaks.
The paper’s authors argue in Science Advances that strengthening testing and death record infrastructure should be treated as core preparedness work, not an afterthought. For Bay Area readers, the analysis puts hard numbers behind what hospitals, community clinics and families saw during those early, chaotic surges: official counts missed a significant share of the human toll, and future crises will need better data and better access to capture the full story.
