COVID-19

=== Infection fatality rate ===
A key metric in gauging the severity of COVID‑19 is the [[infection fatality rate]] (IFR), also referred to as the ''infection fatality ratio'' or ''infection fatality risk''.<ref>{{#invoke:cite journal || vauthors = Mallapaty S | title = How deadly is the coronavirus? Scientists are close to an answer | journal = Nature | volume = 582 | issue = 7813 | pages = 467–468 | date = June 2020 | pmid = 32546810 | doi = 10.1038/d41586-020-01738-2 | s2cid = 219726496 | doi-access = free | title-link = doi | bibcode = 2020Natur.582..467M }}</ref><ref>{{#invoke:cite journal || vauthors = Alwan NA, Burgess RA, Ashworth S, Beale R, Bhadelia N, Bogaert D, Dowd J, Eckerle I, Goldman LR, Greenhalgh T, Gurdasani D, Hamdy A, Hanage WP, Hodcroft EB, Hyde Z, Kellam P, Kelly-Irving M, Krammer F, Lipsitch M, McNally A, McKee M, Nouri A, Pimenta D, Priesemann V, Rutter H, Silver J, Sridhar D, Swanton C, Walensky RP, Yamey G, Ziauddeen H  | title = Scientific consensus on the COVID-19 pandemic: we need to act now | journal = Lancet | volume = 396 | issue = 10260 | pages = e71–e72 | date = October 2020 | pmid = 33069277 | pmc = 7557300 | doi = 10.1016/S0140-6736(20)32153-X }}</ref><ref>{{#invoke:cite journal || vauthors = Meyerowitz-Katz G, Merone L | title = A systematic review and meta-analysis of published research data on COVID-19 infection fatality rates | journal = International Journal of Infectious Diseases | volume = 101 | pages = 138–148 | date = December 2020 | pmid = 33007452 | pmc = 7524446 | doi = 10.1016/j.ijid.2020.09.1464 }}</ref> This metric is calculated by dividing the total number of deaths from the disease by the total number of infected individuals; hence, in contrast to the [[case fatality rate|CFR]], the IFR incorporates asymptomatic and undiagnosed infections as well as reported cases.<ref name="urlGeneralized trapezoidal ogive curves for fatality rate modeling">{{#invoke:cite journal || vauthors = Zhang D, Hu M, Ji Q | title = Financial markets under the global pandemic of COVID-19 | journal = Finance Research Letters | volume = 36 | pages = 101528 | date = October 2020 | pmc = 7402242 | doi = 10.1016/j.csfx.2020.100043 | pmid = 32837360 | bibcode = 2020CSFX....500043D }}</ref>

==== Estimates ====
[[File:Graph of Covid-19 Infection Fatality Ratio by age.png|thumb|The red line shows the estimate of infection fatality rate (IFR), in percentage terms, as a function of age. The shaded region depicts the 95% confidence interval for that estimate. Markers denotes specific observations used in the meta-analysis.<ref name="EJE_levinetal" />]]
[[File:Log Graph of Covid-19 Infection Fatality Ratio by age.png|thumb|The same relationship plotted on a log scale]]

A December 2020 systematic review and meta-analysis estimated that population IFR during the first wave of the pandemic was about 0.5% to 1% in many locations (including France, Netherlands, New Zealand, and Portugal), 1% to 2% in other locations (Australia, England, Lithuania, and Spain), and exceeded 2% in Italy.<ref name="EJE_levinetal">{{#invoke:cite journal || vauthors = Levin AT, Hanage WP, Owusu-Boaitey N, Cochran KB, Walsh SP, Meyerowitz-Katz G | title = Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications | journal = European Journal of Epidemiology | volume = 35 | issue = 12 | pages = 1123–1138 | date = December 2020 | pmid = 33289900 | pmc = 7721859 | doi = 10.1007/s10654-020-00698-1 | doi-access = free | title-link = doi }} [[File:CC BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License] {{Webarchive|url=https://web.archive.org/web/20171016050101/https://creativecommons.org/licenses/by/4.0/ |date=16 October 2017 }}.</ref> That study also found that most of these differences in IFR reflected corresponding differences in the age composition of the population and age-specific infection rates; in particular, the metaregression estimate of IFR is very low for children and younger adults (e.g., 0.002% at age 10 and 0.01% at age 25) but increases progressively to 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85.<ref name="EJE_levinetal" /> These results were also highlighted in a December 2020 report issued by the WHO.<ref>{{#invoke:cite journal||title=Background paper on Covid-19 disease and vaccines: prepared by the Strategic Advisory Group of Experts (SAGE) on immunization working group on COVID-19 vaccines|date=22 December 2020|url=https://apps.who.int/iris/handle/10665/338095|website=World Health Organization|hdl=10665/338095 | author =World Health Organization }}</ref>
{| class="wikitable"
|+class="nowrap"|IFR estimate per age group<br />(to December 2020)<ref name="EJE_levinetal" />
!Age group
!IFR
|-
|0–34
|0.004%
|-
|35–44
|0.068%
|-
|45–54
|0.23%
|-
|55–64
|0.75%
|-
|65–74
|2.5%
|-
|75–84
|8.5%
|-
|85 +
|28.3%
|}
An analysis of those IFR rates indicates that COVID{{nbhyph}}19 is hazardous not only for the elderly but also for middle-aged adults, for whom the infection fatality rate of COVID-19 is two orders of magnitude greater than the annualised risk of a fatal automobile accident and far more dangerous than seasonal [[influenza]].<ref name="EJE_levinetal" />

==== Earlier estimates of IFR ====
At an early stage of the pandemic, the World Health Organization reported estimates of IFR between 0.3% and 1%.<ref>{{#invoke:Cite web||title=Coronavirus disease 2019 (COVID-19) Situation Report – 30 |url=https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200219-sitrep-30-covid-19.pdf |access-date=3 June 2020 |date=19 February 2020}}</ref><ref>{{#invoke:Cite web||title=Coronavirus disease 2019 (COVID-19) Situation Report – 31 |url=https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200220-sitrep-31-covid-19.pdf |access-date=23 April 2020 |date=20 February 2020}}</ref> On 2{{spaces}}July, The WHO's chief scientist reported that the average IFR estimate presented at a two-day WHO expert forum was about 0.6%.<ref name="NYT-20200704dm">{{#invoke:cite news || vauthors = McNeil Jr DG |title=The Pandemic's Big Mystery: How Deadly Is the Coronavirus? – Even with more than 500,000 dead worldwide, scientists are struggling to learn how often the virus kills. Here's why |url=https://www.nytimes.com/2020/07/04/health/coronavirus-death-rate.html |archive-url=https://web.archive.org/web/20200704152005/https://www.nytimes.com/2020/07/04/health/coronavirus-death-rate.html |archive-date=4 July 2020 |url-access=subscription |url-status=live |date=4 July 2020 |work=The New York Times |access-date=6 July 2020}}</ref><ref>{{#invoke:cite news ||title=Global Research and Innovation Forum on COVID-19: Virtual Press Conference |url=https://www.who.int/docs/default-source/coronaviruse/virtual-press-conference---2-july---update-on-covid-19-r-d.pdf |publisher=World Health Organization |date=2 July 2020}}</ref> In August, the WHO found that studies incorporating data from broad serology testing in Europe showed IFR estimates converging at approximately 0.5–1%.<ref>{{#invoke:Cite web||title=Estimating mortality from COVID-19|url=https://www.who.int/news-room/commentaries/detail/estimating-mortality-from-covid-19|access-date=21 September 2020|website=[[World Health Organization]] (WHO)}}</ref> Firm lower limits of IFRs have been established in a number of locations such as New York City and Bergamo in Italy since the IFR cannot be less than the population fatality rate. (After sufficient time however, people can get reinfected).<ref>{{#invoke:cite journal|| vauthors = Shaffer C |date=23 October 2021|title=Covid-19 still rife in Iran |journal=New Scientist|volume=252|issue=3357|pages=10–11|doi=10.1016/S0262-4079(21)01865-0|pmid=34720322|issn=0262-4079|pmc=8536311|bibcode=2021NewSc.252...10S}}</ref> As of 10 July, in New York City, with a population of 8.4&nbsp;million, 23,377 individuals (18,758 confirmed and 4,619 probable) have died with COVID‑19 (0.3% of the population).<ref>{{#invoke:Cite web||title=COVID-19: Data |url=https://www1.nyc.gov/site/doh/covid/covid-19-data.page |publisher=City of New York}}</ref> Antibody testing in New York City suggested an IFR of ≈0.9%,<ref>{{#invoke:cite SSRN||title=SARS-CoV-2, COVID-19, Infection Fatality Rate (IFR) Implied by the Serology, Antibody, Testing in New York City| vauthors = Wilson L |date=May 2020|ssrn=3590771}}</ref> and ≈1.4%.<ref>{{#invoke:cite journal || vauthors = Yang W, Kandula S, Huynh M, Greene SK, Van Wye G, Li W, Chan HT, McGibbon E, Yeung A, Olson D, Fine A, Shaman J  | title = Estimating the infection-fatality risk of SARS-CoV-2 in New York City during the spring 2020 pandemic wave: a model-based analysis | journal = The Lancet. Infectious Diseases | volume = 21 | issue = 2 | pages = 203–212 | date = February 2021 | pmid = 33091374 | pmc = 7572090 | doi = 10.1016/s1473-3099(20)30769-6 }}</ref> In [[Province of Bergamo|Bergamo province]], 0.6% of the population has died.<ref>{{#invoke:Cite web||url=https://medium.com/bccp-uc-berkeley/how-deadly-is-covid-19-data-science-offers-answers-from-italy-mortality-data-58abedf824cf|title=How deadly is COVID-19? Data Science offers answers from Italy mortality data.| vauthors = Modi C |date=21 April 2020 |website=Medium |access-date=23 April 2020}}</ref> In September 2020, the U.S. [[Centers for Disease Control and Prevention]] (CDC) reported preliminary estimates of age-specific IFRs for public health planning purposes.<ref>{{#invoke:Cite web||title=Coronavirus Disease 2019 (COVID-19) |url=https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) |access-date=9 December 2020 |date=10 September 2020}}</ref>