Exploring definitions related to COVID-19 infection and deaths

In a recent study posted to the medRxiv* preprint server, researchers assessed the definitions and reports of coronavirus disease 2019 (COVID-19)-related deaths.

Study: Understanding Definitions and Reporting of Deaths Attributed to COVID-19 in the UK – Evidence from FOI Requests. Image Credit: Terelyuk/Shutterstock

The lack of overall consistency in the definitions related to COVID-19 disease severities by different health authorities has led to erroneous conclusions. This often makes it difficult to differentiate between deaths caused by COVID-19 and human interventions.

About the study

In the present study, researchers collected responses through the Freedom of Information Act (FOIA) to understand the available knowledge regarding the causes of COVID-19-related deaths in the UK.

The team analyzed the understanding of the public authorities of the evaluation of deaths caused by COVID-19 in the UK by assessing FOI requests from 2020 to 2021. The public authorities taken into account during the study included National Health Service (NHS) health trusts, laboratories, and government agencies such as the Department of Health and Social Care and the Public Health England.

The team also searched the WhatDoTheyKnow website for the terms “covid and death” to explore the causes of deaths in the UK. A total of 800 requests from more than 90 persons were found.

The team also recorded the example and the type of respondent in the request and included COVID-19 and related explanatory requests that were based on baseline characteristics including age, region of death, etc. The study focused on three periods of the COVID-19 pandemic to assess the FOI answers that were provided in mid and late 2020 and 2021. The questions were subsequently grouped according to themes that addressed the definitions and reasons for death relevant to COVID-19.


The study results showed that the Office for National Statistics (ONS) provided weekly reports regarding the number of deaths according to the medical certificates of cause of death (MCCD). After a person is reported dead, a medical practitioner writes a medical certificate according to the cause of death, which is further documented at a local authority registration office. This data is subsequently forwarded electronically to the ONS to report statistics related to causes of death.

The NHS England and NHS improvement published the number of patients reported dead in a hospital and who were COVID-19 positive. They also reported whether the dead patient had any pre-existing comorbidities or whether COVID-19 was recorded as the cause of death. All related data was documented against the date of death and not on the date the death was announced. Furthermore, the UK health security agency (UKHSA) collected reports from several sources and provided the daily number of deaths in persons who were polymerase chain reaction ( PCR) positive or rapid lateral flow test positive for COVID-19, irrespective of their place of death. The Care Quality Commission (CQC) also published statistics related to deaths caused by COVID-19 in care homes in England.

The team found that there was no consistency across national bodies regarding definitions provided for causes of death or contributory cause of death. It was noted that medical professionals, as well as nursing home providers, could assign a cause of death. However, when only COVID -19 was mentioned as the cause of death on the death certificate, it was impossible to judge the chain of causality. It was highly unlikely that only COVID-19 infections could cause mortality, without any contribution of risk factors like comorbidities, and pathological aspects that were directly derived from the infection, causing mortality.

The ascertainment of COVID-19 as a cause of death was explored based on several FOIs that enquired about the use of post-mortems and specific tests in different sections on the death certificates. It was found that the lack of post-mortem examinations further added to the dearth of consistency in the definitions of COVID-19 deaths. Inconsistent testing also increased the difficulty of ascertaining the direct cause of death in a patient.

In the FOIs, the ‘sole cause of death’ was related to the underlying health and attempted to understand the death of those who had no related health conditions other than COVID-19. For underlying health conditions, the team also included FOIs that had ‘ do not resuscitate’ orders in place before death. The already remarked inconsistencies in the meaning of specific tests and use of definitions undermined the overall role of COVID-19 infection and related causes of death as compared to other health conditions.


The study findings showed that the current system has led to confusion in the general public regarding the assignment of COVID-19 as the cause of death. The researchers believe that a clear process with consistent definitions is required across the various health organizations to alleviate this confusion .

Furthermore, the system also needs thorough validation by adding post-mortem-related data to improve and ensure accuracy.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.


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