What is the risk of dying from this COVID-19 for an infected person?
Text updated on 2020-10-18
The likelihood of dying from the COVID-19 diseasevaries greatly depending on age, other risk factors, and type of variant. It is almost zero for children (< 0.006%), adolescents and young adults, and is high in the elderly (~ 8% for people over 80 years old). For the general population, estimates fluctuate between 0.3% and 1.5%.
The probability of dying after being infected with the SARS-CoV-2 virus, or "case-fatality rate", can be calculated by dividing the number of people who have died from the COVID-19 disease by the total number of people infected with the virus. However, the total number of people infected is difficult to know precisely because many develop only minor symptoms (these people are said to be pauci-symptomatic or asymptomatic) and are not routinely tested.
Epidemiologists distinguish two lethality rates for infectious diseases:
- Case Fatality Rate (clinical): the proportion of deaths to the number of cases detected by tests (CFR).
- Infection FatalityRate (IFR): the proportion of deaths to the number of people actually infected.
The case-fatality rate is higher than the actual case-fatality rate. It varies greatly between countries (typically between 1 and 20%) because it depends on the country's :
- the propensity of a country to test potentially infected individuals: typically PCR tests are performed on people with symptoms of the disease COVID-19 or who have been in contact with a person identified as infected.
- Reliability of tests for the detection of the SARS-CoV-2 virus: with nasopharyngeal PCR tests, it is estimated that about 30% of infected persons test negative due to poor sampling or a reduced amount of virus in the nose after a certain period of infection.
The case-fatality rate of the infection corresponds to the actual case-fatality rate but is more difficult to calculate because the total number of infected persons has to be estimated. This can be done by conducting regular large-scale PCR testing campaigns that include asymptomatic individuals or by serological tests that detect whether a person has been previously infected by SARS-CoV-2. Currently, it is estimated that the case-fatality rate of infection in a population distributed across all ages is in the range of 0.3 - 0.8%.
Between March 2020 and June 2020, the in-hospital mortality rate of COVID-19 patients decreased in several countries (Italy, United Kingdom, and the United States). See the question Has the management of patients with COVID-19 improved?
Explanation of the difference between the case-fatality rate of infected persons and the case-fatality rate of detected cases. Many infected persons are not detected because they are asymptomatic or paucisymptomatic, and population sampling, which is biased towards persons in respiratory distress, leads to an underestimation of the number of infected persons.Bar-On, Y. M., Flamholz, A., Phillips, R., & Milo, R. (2020). SARS-CoV-2 (COVID-19) by the numbers. Elife, 9, e57309.
A "meta-analysis" of 13 studies of the Infection Fatality Rate (IFR) conducted between February and April 2020 indicates that, overall, this rate can be estimated at 0.75% (0.49% - 1.01%) with differences related to the age pyramid of each population.Meyerowitz-Katz, G., & Merone, L. (2020). A systematic review and meta-analysis of published research data on COVID-19 infection-fatality rates. medRxiv.
Analysis of 95,218 people hospitalised due to COVID-19 in France leading to 16,386 deaths: it is estimated that 3.6% of infected people are hospitalised and 0.7% die.Salje, H., Kiem, C. T., Lefrancq, N., Courtejoie, N., Bosetti, P., Paireau, J., ... & Le Strat, Y. (2020). Estimating the burden of SARS-CoV-2 in France. Science.
In Lombardy, based on the comparison of mortality recorded in 10 municipalities in relation to the years 2015-2019, the global IFR is estimated at 1.29%. It varies from 0.05% for people under 60 to 4.25% for people over 60.Rinaldi, G., & Paradisi, M. (2020). An empirical estimate of the infection fatality rate of COVID-19 from the first Italian outbreak. medRxiv.
Comparison of case fatality rates between Italy, China, and South Korea.Onder, G., Rezza, G., & Brusaferro, S. (2020). Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy. Jama.
A meta-analysis of cases COVID-19 in China estimates a case-fatality rate of 0.66% for the global population as of March 25, 2020.Verity, R., Okell, L. C., Dorigatti, I., Winskill, P., Whittaker, C., Imai, N., ... & Dighe, A. (2020). Estimates of the severity of the coronavirus disease 2019: a model-based analysis. The Lancet Infectious Diseases.
A meta-analysis of the risk factors for dying from the disease COVID-19 was conducted on 17 million patients in American hospitals and revealed gender, ethnicity, and strong dependence on co-morbid factors:Williamson, E., Walker, A. J., Bhaskaran, K. J., Bacon, S., Bates, C., Morton, C. E., .... Goldacre, B. (2020). OpenSAFELY: factors associated with COVID-19-related hospital death in the linked electronic health records of 17 million adult NHS patients. medRxiv, 2020.2005.2006.20092999. doi:10.1101/2020.05.06.20092999
A large-scale serological study in the village of Gangelt, an initial cluster in Germany where a festival was held and where 80% of the population was screened for the presence of antibodies indicating a SARS-CoV-2 infection, estimates the case-fatality rate of infected persons to be 0.37%.Streeck, H., Schulte, B., Kuemmerer, B., Richter, E., Höller, T., Fuhrmann, C., ... & Eschbach-Bludau, M. (2020). Infection fatality rate of SARS-CoV-2 infection in a German community with a super-spreading event. medRxiv.
A study by the University of Berkeley published in April 2020 estimated from the monthly mortality observed from 2015 to 2019 that in Italy, the actual number of victims of COVID-19 is twice the figure reported in hospitals and that only one person out of 35 infected persons was confirmed. Researchers note that in cities such as Bergamo in Italy where there were 6,000 victims per 1 million inhabitants (or 0.6%), the case-fatality rate of infected people was necessarily higher than 0.6% under these conditions.Modi, C., Boehm, V., Ferraro, S., Stein, G., & Seljak, U. (2020). Total COVID-19 Mortality in Italy: Excess Mortality and Age Dependence through Time-Series Analysis. medRxiv.
Estimated case-fatality rate of infected persons in France on May 7, 2020 at 0.5%:Roques, L, Klein, E, Papaix, J, Sar, A, Soubeyrand, S. Using early data to estimate the actual infection fatality ratio from COVID-19 in France. doi: https://doi.org/10.1101/2020.03.22.20040915
A study from May 14, 2020, based on the excess mortality observed in comparison with the previous year, estimates the IFR at 0.5% in New York City and 0.61% in Lombardy. Note that the estimated number of COVID-19 victims is estimated at ~50,000 people as of May 9, 2020, instead of 33,000 or +50% compared to the announced figures. The authors conclude that this difference derives from the elderly people affected by the virus in their homes.Modi, C, Boehm, V, Ferraro, S, Stein, G, Seljak, U. How deadly is COVID-19? A rigorous analysis of excess mortality and age-dependent fatality rates in Italy
One model estimates that the case-fatality rate of the infection could be 10 times lower than the original estimates that were close to 1%.Delius, GW, Powell, BJ, Bees, MA, Constable, GW, MacKay, NJ, Pitchford JW (2020). More prevalent, less deadly? Bayesian inference of the COVID19 Infection Fatality Ratio from mortality data
Estimated case-fatality rate of the infection using a Bayesian model of SIR ('Susceptible, Infectious, or Recovered') at 0.17% at the beginning of the epidemic and gradually increasing to 1.8%:Chow*, CC, Chang, JC, Gerkin RC, Vattikuti, S. Global prediction of unreported SARS-CoV2 infection from observed COVID-19 cases
Study conducted in the UK between October 1, 2020 and February 12, 2021 in 109,812 people over 30 years of age infected with SARS-CoV-2 and followed for 28 days. The authors compared the mortality rate in two groups of patients: a group of 54,906 people infected with the UK variant (identified by non-recognition of the Spike protein with an RT-PCR test) and a group of 54,906 people infected with the non-mutated form of SARS-CoV-2. The groups were matched for age, ethnicity, gender, socioeconomic status, and region of residence. There were 227 deaths in the group infected with the UK variant and 141 deaths in the group infected with the non-mutated form of coronavirus. For the UK variant, the rate is 4.1 deaths per 1,000 cases and for the non-mutated form the rate is 2.5 deaths per 1,000 cases, a 64% increase in mortality risk with the UK variant.Challen, R., Brooks-Pollock, E., Read, J. M., Dyson, L., Tsaneva-Atanasova, K., & Danon, L. (2021). Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: matched cohort study. BMJ, 372.