Covid's Hidden Sepsis Toll Emerges as Studies Find It in up to 93% of Deaths but Just 9% Were Coded

Sepsis appeared in 9.3% of US COVID-19-related death records in 2020, according to a peer-reviewed analysis published on 29 June 2023. The study examined 384,536 deaths in which COVID-19 was recorded as an underlying or contributing cause.

Separate hospital research identified sepsis in 26 of 28 patients who died with COVID-19, approximately 93%. Those figures concern different populations and cannot establish how many US deaths involved sepsis that went unrecorded.

US Study Examined Death Records

Sepsis is life-threatening organ dysfunction caused by a dysregulated response to infection. It can arise from viral infections as well as bacterial and other infections.

Lavi Oud and John Garza's paper, 'The Impact of COVID-19 on Sepsis-Related Mortality in the United States', was published in the 'Journal of Clinical Medicine Research'. It used the CDC WONDER Multiple Cause of Death database and selected diagnostic codes to identify records mentioning sepsis, COVID-19 or both.

The researchers found sepsis recorded in 35,807 of the 384,536 COVID-19-related deaths. Across the wider dataset, they identified 242,630 sepsis-related deaths in 2020, compared with 206,549 predicted by a model based on 2015–2019 trends and adjusted for population.

Observed sepsis-related deaths were therefore approximately 17% above the predicted number. That difference does not establish how many additional deaths were directly caused by COVID-19, other infections or indirect effects of the pandemic.

The authors concluded that death-certificate data 'may have substantially underestimated the toll of sepsis-related deaths in the USA during the first year of the pandemic'. They also acknowledged that the correct number of sepsis-related deaths among people who died with COVID-19 remained unknown.

Recording varied geographically. Sepsis appeared in 6.7% of COVID-19-related death records in the region including New York and New Jersey, compared with 12.8% in the region including Arizona, California, Hawaii and Nevada.

Those differences do not, by themselves, identify their cause. Death certificates can be affected by documentation practices, diagnostic classifications and differences between patient populations.

Clinical Studies Use Different Measures

The hospital study behind the approximately 93% figure reviewed 200 randomly selected COVID-19 patients at four Massachusetts hospitals between March 2020 and March 2021. Researchers identified sepsis in 26 of the 28 patients who died in hospital.

That clinical review differs from searching national death records for selected codes. It does not mean that 93% of all US COVID-19 deaths involved sepsis, or that the difference between 93 and 9.3% measures nationwide under-recording.

Oud and Garza said the reasons for the recording gap were unclear. They suggested uncertainty over how COVID-19-related organ dysfunction was classified and documented as one possible explanation.

They also questioned the terminology used in the 2020 Surviving Sepsis Campaign guidance for critically ill COVID-19 patients. That was the authors' interpretation, not evidence that the guidance caused inadequate treatment or that clinicians deliberately omitted sepsis.

French research identified a related classification issue. A study published in 'BMC Infectious Diseases' on 29 April 2025 examined national hospital data for patients aged 15 and over during 2018–2022.

Viral sepsis represented 1.5% of identified cases before the pandemic, rising to 9.4% in 2020 and 13.6% in 2021, before falling to 6.9% in 2022. Its authors called for clearer definitions and more explicit viral-sepsis codes, while acknowledging possible misclassification and changing coding guidance.

Hospital Admissions Are Separate Evidence

A separate Agency for Healthcare Research and Quality report, published in September 2024, examined the hospital burden of sepsis through 2021.

Sepsis-related inpatient stays increased from 1.8 million in 2016 to 2.5 million in 2021. These figures count hospital stays rather than necessarily representing the same number of individual patients.

AHRQ said COVID-19 contributed significantly to the increase and reported approximately 300,000 in-hospital deaths involving sepsis in 2021. These hospital findings use a different dataset, period and measure from the 2020 national death-certificate analysis.

Commercial Commentary Highlights Older Research

The earlier findings were highlighted in a Pharmaphorum opinion article published on 5 October 2026 by Dima Romashin, founder and chief executive of Efferon, a company developing blood-purification technology.

Romashin argued that sepsis should receive greater attention in preparations for future respiratory pandemics. He called for more specific surveillance codes, additional dialysis capacity and faster diagnostic testing.

His company's work gives him a commercial interest in critical-care provision. His recommendations are commentary, not conclusions established by the mortality analysis or a substitute for clinical guidance.

The studies raise questions about how viral sepsis is defined and recorded. They do not establish deliberate concealment, determine whether individual patients received appropriate care or demonstrate the benefits of a particular blood-purification treatment.