Fact Check-Why those with comorbidities are still counted as COVID-19 deaths

Some social media users have this month cited a 2020 U.S. National Center for Health Statistics (NCHS) database on fatalities linked to COVID-19 to try to prove that the number of coronavirus deaths in the country has been significantly overstated - by extrapolating from the percentage of people who the NCHS says have died of COVID-19 alone, and not of the virus in conjunction with another illness, condition, or comorbidity.

Comorbidities can cause individuals to be at higher risk of severe COVID-19, but the virus can still be their cause of death.

The term comorbidity refers to having two or more diseases at the same time ( here ). While an individual may live with a comorbidity, the cause of death is the disease or injury which started the train of events which directly led to death ( here ), ( here ), ( here ).

Comorbidities, while they may raise the risk of severe disease, are not necessarily the cause of death. The virus itself can be the cause of otherwise preventable death among those who had manageable health conditions ( here ).

“Some comorbidities are important to know about as they help us understand the risk of the disease or condition of interest in different populations. A comorbidity may contribute to the severity of the disease under consideration... but the underlying cause of death would not be the comorbidity,” Susan Ellenberg, Emeritus Professor of Biostatistics and Epidemiology at the University of Pennsylvania told Reuters.

The coronavirus can also cause conditions or exacerbate pre-existing conditions that ultimately lead to death, such as respiratory weakness leading to respiratory failure, which may be listed as conditions along with COVID-19 on a death certificate, But the virus itself is the cause of death.

The data cited by the social media users seeking to show the pandemic has been overstated is headlined: “Conditions contributing to deaths involving COVID-19, by age group, United States. Week ending 2/1/2020 to 12/5/2020” ( here ). The dataset - complied by the Centers for Disease Control and Prevention (CDC), which the NCHS is part of - details the types of health conditions and contributing causes in conjunction with deaths involving COVID-19 mentioned on death certificates.

According to the database, for 6% of the deaths, COVID-19 was the only cause mentioned while other conditions were listed along with COVID-19 for the remaining 94%.

By extrapolating that 6% figure from the actual number of deaths attributed to the coronavirus as of Jan. 9, 2022 (836,000), users estimated that 50,000 died of COVID-19 only, implying that the rest had died of different causes.

One user said on Twitter: “According to the CDC, only 50,000 people died from COVID-ONLY as opposed to the 836,000 figure I need new conspiracy theories, all my old ones became FACTS” ( here ). The tweet had over 30,000 likes at the time of writing. Other examples on social media can be seen ( here ), ( here ), ( here ).

This is a “misrepresentation of the data,” a spokesperson for NCHS told Reuters.

“Death certificates, on which these data are based, are designed to elicit a causal pathway, or chain of events leading to death. Physicians, medical examiners, and coroners that report and certify the cause of death on death certificates, if they correctly follow the instructions, will typically report more than one condition,” they said.

A CDC document released in April 2020 shows the standard format for such reporting ( here ).

On such reports, it is “not unusual to see something like “acute respiratory failure” due to “viral pneumonia” due to “COVID-19”. On such a record, there would be two conditions reported in addition to COVID-19. But this is clearly a death caused by COVID-19. I.e., COVID-19 was the underlying cause as it initiated the chain of events leading to death. Respiratory failure and pneumonia are clearly reported as complications of COVID-19 and not as competing conditions,” they said.

In a separate section, the certifier is also instructed to report any significant conditions that contributed to death but were not part of the causal sequence.

“So, for COVID-19 deaths, it is not unusual to see conditions such as COPD [Chronic Obstructive Pulmonary Disease], diabetes or dementia, that are known to result in more severe COVID infection, reported in this section. Such contributing factors are also not to be seen as competing underlying causes,” the spokesperson said.

“Currently, based on the death certificate data we have received, for 91% of death certificates with COVID-19 reported, COVID-19 is clearly the underlying cause. In 9% of cases, it was a reported as a significant factor contributing to death,” they added.

Dr Lance Waller, Professor in the Department of Biostatistics and Bioinformatics at Rollins School of Public Health at Emory University, added: “Limiting COVID death counts to only those with ONLY COVID listed would skip all of the deaths if the result of COVID ‘tips things over the edge’,” he added.

Dr Marc Larsen, an emergency medicine physician who serves as Incident Command Operations Chair for COVID-19 at St. Luke’s Hospital in Kansas City discussed the database with Reuters via email in Aug. 2020 when similar claims circulated online and said that when filling out death certificates, physicians will typically use a standard format and list the primary cause of death as well as other contributing factors (read more here).

NCHS information on data-collection pertaining to COVID-19 deaths can be seen ( here ). More recent data on conditions contributing to COVID-19 deaths can be seen ( here ).


Missing context. The 6% figure used by users online to calculate COVID-19-only deaths originates from a 2020 database and represents the percentage of death certificates with COVID-19 listed as the only cause mentioned. This extrapolation is misleading, however, and doesn’t take into account that conditions listed in a death certificate may be caused by the virus itself. While a comorbidity may cause someone to be at higher risk of COVID-19, the comorbidity is not necessarily the cause of death.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here.