Editing Pandemic (section)

== Definition ==
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A medical dictionary definition of pandemic is "an [[epidemic]] occurring on a scale that crosses international boundaries, usually affecting people on a worldwide scale".<ref name=Porta2008>{{cite book| veditors = Porta M |title=Dictionary of Epidemiology|url=https://books.google.com/books?id=3Dr8dyuzvTkC&pg=PA179|access-date=14 September 2012|year=2008|publisher=Oxford University Press|isbn=978-0-19-531449-6|page=179}}</ref> A disease or condition is not a pandemic merely because it is widespread or kills many people; it must also be infectious. For instance, [[cancer]] is responsible for many deaths but is not considered a pandemic because the disease is not [[Infection#Contagiousness|contagious]]—i.e. easily transmissible—and not even simply [[Infection|infectious]].<ref>{{cite book | vauthors = Dumar AM |title=Swine Flu: What You Need to Know |date=2009 |publisher=Wildside Press LLC |isbn=978-1434458322 |page=7}}</ref> This definition differs from colloquial usage in that it encompasses outbreaks of relatively mild diseases.<ref>{{cite journal | vauthors = Morens D, Folkers G, Fauci A |date=1 October 2009 |title=What Is a Pandemic? |url=https://academic.oup.com/jid/article/200/7/1018/903237 |access-date=7 June 2023 |journal=The Journal of Infectious Diseases |volume=200 |issue=7 |pages=1018–1021 |doi=10.1086/644537 |pmid=19712039 }}</ref><ref>{{cite journal | vauthors = Doshi P | title = The elusive definition of pandemic influenza | journal = Bulletin of the World Health Organization | volume = 89 | issue = 7 | pages = 532–538 | date = July 2011 | pmid = 21734768 | pmc = 3127275 | doi = 10.2471/BLT.11.086173 }}</ref>

The [[World Health Organization]] (WHO) has a category of [[Public health emergency of international concern|Public Health Emergency of International Concern]], defined as "an extraordinary event which is determined to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response".<ref>{{cite web |date=19 December 2019 |title=Emergencies: International health regulations and emergency committees |url=https://www.who.int/news-room/questions-and-answers/item/emergencies-international-health-regulations-and-emergency-committees |access-date=7 June 2023 |website=World Health Organization }}</ref> There is a rigorous process underlying this categorization and a clearly defined trajectory of responses.<ref>{{cite web | vauthors = Ross E |date=20 October 2022 |title=What is the difference between a pandemic and a PHEIC? (Video) |url=https://www.chathamhouse.org/2022/10/what-difference-between-pandemic-and-pheic |access-date=7 June 2023 |website=Chatham House, The Royal Institute of International Affairs}}</ref>

A WHO-sponsored international body, tasked with preparing an [[International Treaty on Pandemic Prevention, Preparedness and Response|international agreement on pandemic prevention, preparedness and response]] has defined a pandemic as "the global spread of a pathogen or variant that infects human populations with limited or no immunity through sustained and high transmissibility from person to person, overwhelming health systems with severe morbidity and high mortality, and causing social and economic disruptions, all of which require effective national and global collaboration and coordination for its control".<ref>{{cite web |date=1 February 2023 |title=Zero draft of the WHO convention, agreement or other international instrument on pandemic prevention, preparedness and response ("WHO CA+") |url=https://apps.who.int/gb/inb/pdf_files/inb4/A_INB4_3-en.pdf |access-date=7 June 2023 |website=World Health Organization – Intergovernmental Negotiating Body}}</ref>

The word comes from the [[Ancient Greek|Greek]] {{Lang|grc|παν-}} {{Lang|grc-latn|pan-}} meaning {{Gloss|all, every}}, and {{Lang|grc|δῆμος}} {{Lang|grc-latn|demos}} {{Gloss|people}}.

=== Parameters ===
A common early characteristic of a pandemic is a rapid, sometimes [[Exponential growth|exponential]], growth in the number of infections, coupled with a widening geographical spread.<ref>{{Cite journal |last1=Foster |first1=Grant |last2=Elderd |first2=Bret D |last3=Richards |first3=Robert L |last4=Dallas |first4=Tad |date=2022-09-01 |editor-last=Wilson |editor-first=Ian |title=Estimating R 0 from early exponential growth: parallels between 1918 influenza and 2020 SARS-CoV-2 pandemics |url=https://academic.oup.com/pnasnexus/article/doi/10.1093/pnasnexus/pgac194/6702748 |journal=PNAS Nexus |language=en |volume=1 |issue=4 |pages=pgac194 |doi=10.1093/pnasnexus/pgac194 |issn=2752-6542 |pmc=9802102 |pmid=36714850}}</ref>

[[World Health Organization|WHO]] utilises different criteria to declare a [[Public health emergency of international concern|Public Health Emergency of International Concern]] (PHEIC), its nearest equivalent to the term ''pandemic.''<ref>{{Cite web |last=Ross |first=Emma |date=20 Oct 2022 |title=What is the difference between a pandemic and a PHEIC (Video explainer) |url=https://www.chathamhouse.org/2022/10/what-difference-between-pandemic-and-pheic |access-date=25 August 2023 |website=Chatham House, The Royal Institute of International Affairs |quote=There's a whole infrastructure and official process around designating something a PHEIC and designating that an outbreak is no longer a PHEIC. There's none of that when it comes to calling an outbreak pandemic.}}</ref> The potential consequences of an incident are considered, rather than its current status.<ref>{{Cite journal |last1=Wilder-Smith |first1=Annelies |last2=Osman |first2=Sarah |date=2020-12-23 |title=Public health emergencies of international concern: a historic overview |journal=Journal of Travel Medicine |language=en |volume=27 |issue=8 |doi=10.1093/jtm/taaa227 |issn=1195-1982 |pmc=7798963 |pmid=33284964}}</ref> For example, [[polio]] was [[Polio eradication#2011–2015|declared a PHEIC]] in 2014 even though only 482 cases were reported globally in the previous year;<ref>{{Cite web |title=GHO {{!}} By category {{!}} Poliomyelitis - Reported cases by country |url=https://apps.who.int/gho/data/node.main.WHS3_49?lang=en |access-date=2023-08-25 |website=WHO}}</ref> this was justified by concerns that polio might break out of its endemic areas and again become a significant health threat globally.<ref>{{Cite web |date=5 May 2014 |title=WHO statement on the meeting of the International Health Regulations Emergency Committee concerning the international spread of wild poliovirus |url=https://www.who.int/news/item/05-05-2014-who-statement-on-the-meeting-of-the-international-health-regulations-emergency-committee-concerning-the-international-spread-of-wild-poliovirus |access-date=25 August 2023 |website=World Health Organization |language=en}}</ref> The PHEIC status of polio is reviewed regularly and is ongoing, despite the small number of cases annually.{{Efn|As of August 2023}}<ref>{{Cite web |title=Statement of the Thirty-sixth Meeting of the Polio IHR Emergency Committee |url=https://www.who.int/news/item/25-08-2023-statement-of-the-thirty-sixth-meeting-of-the-polio-ihr-emergency-committee |access-date=2023-08-25 |website=www.who.int |language=en}}</ref>

The end of a pandemic is more difficult to delineate. Generally, past epidemics and pandemics have faded out as the diseases become accepted into people's daily lives and routines, becoming [[Endemic (epidemiology)|endemic]].<ref>{{Cite journal |last1=Charters |first1=Erica |last2=Heitman |first2=Kristin |date=February 2021 |title=How epidemics end |journal=Centaurus |language=en |volume=63 |issue=1 |pages=210–224 |doi=10.1111/1600-0498.12370 |issn=0008-8994 |pmc=8014506 |pmid=33821019}}</ref> The transition from pandemic to endemic may be defined based on:

* a high proportion of the global population having immunity (through either natural infection or vaccination)
* fewer deaths
* health systems step down from emergency status
* perceived personal risk is lessened
* restrictive measures such as [[Travel during the COVID-19 pandemic|travel restrictions]] removed
* less coverage in public media.<ref name=":0">{{Cite journal |last=Ioannidis |first=John P. A. |date=June 2022 |title=The end of the COVID-19 pandemic |journal=European Journal of Clinical Investigation |language=en |volume=52 |issue=6 |pages=e13782 |doi=10.1111/eci.13782 |issn=0014-2972 |pmc=9111437 |pmid=35342941}}</ref><ref>{{Cite news |last=Steenhuysen |first=Julie |date=2021-11-17 |title=Fauci says boosters for all key to U.S. reaching COVID-19 endemic level |language=en |work=Reuters |url=https://www.reuters.com/world/us/fauci-says-us-can-reach-covid-endemic-level-rather-than-pandemic-next-year-2021-11-16/ |access-date=2023-08-22}}</ref>

An endemic disease is always present in a population, but at a relatively low and predictable level. There may be periodic spikes of infections or seasonality, (e.g. [[influenza]]) but generally the burden on health systems is manageable.<ref name=":0" />