Editing Pandemic (section)

=== 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" />