Inaccurate: Some posts misinterpret the age-specific IFRs reported by the U.S. Centers for Disease Control and Prevention as percentages. For example, some posts report the IFR for people aged 70 and above as 0.054% rather than 5.4%. This simple mathematical error underestimates the true IFRs.
FULL CLAIM: COVID-19 mortality rates are very low, therefore COVID-19 is not an important public health concern; if you are 0-19 years old, you have a 0.00003% chance of dying from COVID-19; ... if you are 70+ years old, you have a 0.054% chance of dying from COVID-19.
REVIEW
The claim that the COVID-19 pandemic response is unwarranted has taken many forms. Some involve misleading comparisons with other respiratory diseases like the flu and tuberculosis, while others rely on misinterpretations of COVID-19 mortality reports and unsupported accounts of fabricated COVID-19 test results. In September 2020, numerous Facebook posts making the claim that COVID-19 is not an important public health concern due to its low infection mortality ratio (IFR) emerged (see examples here and here). These claims highlight the age-specific IFR data that was added to the U.S. Centers for Disease Control and Prevention (CDC) website on 10 September 2020 (see archive of website with the update note). These posts have gone viral, receiving more than 37,000 shares.
The IFR of a disease is the proportion of deaths among all infections, both confirmed cases as well as undetected cases. Estimating the number of undetected cases is a challenge, although scientists can approximate this number in different ways. For instance, they can conduct seroprevalence studies to estimate how many people in a population have been infected or extrapolate incidence from groups that have been thoroughly tested, like the Diamond Princess cruise ship passengers. The IFR is one factor used to assess the public health threat posed by a disease and the subsequent response. The IFR data recently reported on the CDC website is based on a study published in the journal PLOS Medicine in July 2020[1] using data from China, Austria, Germany, Italy, Spain, and Switzerland.
Fox News and some of the posts citing these statistics misinterpreted these ratios as percentages using a simple mathematical error, as can be seen in this post and this Fox News show. These errors create the false impression that mortality rates from COVID-19 are much lower than they actually are.
For instance, a ratio of 1 to 2 is equivalent to 0.5. To convert this value into a percentage, multiply 0.5 by 100% to get 50%. Therefore, when converted to percentages, the age-specific IFRs reported on the CDC’s website are as follows: 0.003% for those aged 0 to 19 years old, 0.02% for those aged 20 to 49 years old, 0.5% for those aged 50 to 69 years old and 5.4% for those aged 70 and above. Hence the posts that misinterpreted the numbers on the CDC website as percentages underestimate the true percentages by a factor of 100.
Even posts that cite accurate percentages for the age-specific IFRs as evidence that the COVID-19 pandemic response is an overreaction are misleading (see example). Determining the public health threat posed by COVID-19 requires considering multiple aspects of the disease, not solely IFRs. Using IFR alone as a predictor of COVID-19’s severity fails to account for the fact that there are multiple detrimental outcomes even for COVID-19 survivors, as this Health Feedback review explained.
Specifically, scientists observed that some survivors suffer from damage to various organs, including the lungs and heart, as well as the nervous system. Such damage could lead to chronic health problems, as this news article in Science reported, although it is currently unclear how long such damage persists and how many survivors will be affected. Despite the uncertainties, the long-term health effects of COVID-19 can be so severe that physicians and researchers are preparing to provide rehabilitation services to patients to facilitate their return to a functional life[2,3], such as physiotherapy and speech therapy.
Finally, even a small IFR can translate into a large number of deaths if the virus spreads among a large group of people. Indeed, despite COVID-19’s relatively low IFR, the U.S. has recorded more than 200,000 COVID-19 deaths at the time of this review’s publication, and there have been more than 1 million COVID-19 deaths worldwide, according to the Coronavirus Resource Center by Johns Hopkins University.
Another way of measuring the COVID-19 pandemic’s impact on mortality is to evaluate whether there are more deaths in 2020 from all causes relative to previous years. This is known as excess mortality or excess death. The New York Times reported that at least 200,000 excess deaths already occurred in the U.S. over a period of less than six months between March and August 2020.
Overall, Fox News and posts claiming that the pandemic response is an overreaction because COVID-19 IFRs are relatively low mislead readers by omitting important context. Such posts, which often rely on simple mathematical mistakes, do not account for the high number of COVID-19 cases and the occurrence of chronic health problems in some COVID-19 survivors. These factors are also important to consider when evaluating whether a disease is a public health concern.
REFERENCES
- 1 – Hauser et al. (2020) Estimation of SARS-CoV-2 mortality during the early stages of an epidemic: A modeling study in Hubei, China, and six regions in Europe. PLOS Medicine.
- 2 – Barker-Davies et al. (2020) The Stanford Hall consensus statement for post-COVID-19 rehabilitation. British Journal of Sports Medicine.
- 3 – De Biase et al. (2020) The COVID-19 rehabilitation pandemic. Age and Ageing.
