110-469: A pandemic ( / p æ n ˈ d ɛ m ɪ k / pan-DEM-ik ) is an epidemic of an infectious disease that has a sudden increase in cases and spreads across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of
220-467: A growing human population , are the primary drivers of this destruction. According to Peter Daszak , the chair of the group who produced the report, "there is no great mystery about the cause of the Covid-19 pandemic or any modern pandemic. The same human activities that drive climate change and biodiversity loss also drive pandemic risk through their impacts on our environment." Proposed policy options from
330-533: A zoonotic origin, having originated in nonhuman primates in Central Africa and transferred to humans in the early 20th century. The most frequent mode of transmission of HIV is through sexual contact with an infected person. There may be a short period of mild, nonspecific symptoms followed by an asymptomatic (but nevertheless infectious) stage called clinical latency - without treatment, this stage can last between 3 and 20 years. The only way to detect infection
440-636: A PHEIC at this stage", a notion that is not part of the PHEIC criteria laid down in the IHR. After confirmed cases of Ebola in neighbouring Uganda in June 2019, Tedros Adhanom , the director-general of the WHO, announced that the third meeting of a group of experts would be held on 14 June 2019 to assess whether the Ebola spread had become a PHEIC. The conclusion was that while the outbreak
550-691: A PHEIC would be an inappropriate way to raise money for the epidemic. Following a visit to the DRC in July 2019, Rory Stewart , the UK's DfID minister, called for the WHO to declare it an emergency. Acknowledging a high risk of spread to the capital of North Kivu, Goma , a call for a PHEIC declaration was published on 10 July 2019 in The Washington Post by Daniel Lucey and Ron Klain (the former United States Ebola response coordinator ). Their declaration stated that "in
660-441: A PHEIC, as the outbreak was considered over. On 30 January 2020, the WHO declared the outbreak of COVID-19 , centered on Wuhan in central China , a PHEIC. On 5 May 2023, the WHO ended the PHEIC declaration for COVID-19. On the date of the declaration, there were 7,818 cases confirmed globally, affecting 19 countries in five of the six WHO regions. Previously, the WHO had held EC meetings on 22 and 23 January 2020 regarding
770-501: A PHEIC, it had occurred in only three countries. Therefore, it was argued that the declaration of the H1N1 outbreak as a PHEIC, was fueling public fear. A 2013 study sponsored by the WHO estimated that, although similar in magnitude to seasonal influenza, it cost more life-years than seasonal flu, due to a shift toward mortality among persons less than 65 years of age. The second PHEIC was the 2014 polio declaration , issued on 5 May 2014 with
880-646: A PHEIC, the WHO Director-General is required to take into account factors that include the risk to human health and international spread as well as advice from an international committee of experts, the IHR Emergency Committee (EC), one of whom should be an expert nominated by the State within whose region the event arises. Rather than being a standing committee, the EC is created on an ad hoc basis. Until 2011,
990-540: A PHEIC, with six in favor and nine against. On 23 July 2022, the WHO director-general declared the outbreak a PHEIC. On 11 May 2023, the WHO ended the PHEIC declaration for Mpox, six days after doing so for COVID-19. On the date of the declaration, there were 17,186 cases reported globally, affecting 75 countries in all six WHO regions, with five deaths reported outside Africa and 72 deaths in African countries. The WHO had previously held an EC meeting on 23 June 2022 regarding
1100-712: A PHEIC. As of November 2021, taking into account recent events in Afghanistan, a large number of unvaccinated children, increasing mobile people in Pakistan and the risks associated with the COVID-19 pandemic among others, polio remains a PHEIC. Confirmed cases of Ebola were being reported in Guinea in December 2013 and Liberia in March 2014 and Sierra Leone by May 2014. On 8 August 2014, following
1210-448: A case of Ebola was confirmed in Goma, which has an international airport and a highly mobile population. Subsequently, the WHO announced a reconvening of a fourth EC meeting on 17 July 2019, when they officially announced it "a regional emergency, and by no means a global threat" and declared it as a PHEIC, without restrictions on trade or travel. In response to the declaration, the president of
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#17328442294391320-540: A category of 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 ". There is a rigorous process underlying this categorization and a clearly defined trajectory of responses. A WHO-sponsored international body, tasked with preparing an international agreement on pandemic prevention, preparedness and response has defined
1430-430: A cause of great concern to health professionals. Every year, nearly half a million new cases of multidrug-resistant tuberculosis (MDR-TB) are estimated to occur worldwide. China and India have the highest rate of MDR-TB. WHO reports that approximately 50 million people worldwide are infected with MDR-TB, with 79 percent of those cases resistant to three or more antibiotics. Extensively drug-resistant tuberculosis ( XDR-TB )
1540-429: A common source exposure or an environmental vector may spread a zoonotic diseases agent. Preparations for an epidemic include having a disease surveillance system; the ability to quickly dispatch emergency workers, especially local-based emergency workers; and a legitimate way to guarantee the safety and health of health workers. Effective preparations for a response to a pandemic are multi-layered. The first layer
1650-447: A death toll of 6.9 million. It is considered likely that the virus will eventually become endemic and, like the common cold, cause less severe disease for most people. HIV/AIDS was first identified as a disease in 1981, and is an ongoing worldwide public health issue. Since then, HIV/AIDS has killed an estimated 40 million people with a further 630,000 deaths annually; 39 million people are currently living with HIV infection. HIV has
1760-595: A disease above what is normally expected in that population in that area." The term "outbreak" can also apply, but is usually restricted to smaller events. Any sudden increase in disease prevalence may generally be termed an epidemic. This may include contagious disease (i.e. easily spread between persons) such as influenza ; vector-borne diseases such as malaria ; water-borne diseases such as cholera ; and sexually transmitted diseases such as HIV/AIDS . The term can also be used for non-communicable health issues such as obesity . The term epidemic derives from
1870-449: A disease epidemic. By the early 17th century, the terms endemic and epidemic referred to contrasting conditions of population-level disease, with the endemic condition a " common sicknesse " and the epidemic " hapning in some region, or countrey, at a certaine time, ....... producing in all sorts of people, one and the same kind of sicknesse ". The term "epidemic" is often applied to diseases in non-human animals, although " epizootic "
1980-418: A disease which has caused epidemics in the past may return in the future. It is also possible that little known diseases may become more virulent; in order to encourage research, a number of organisations which monitor global health have drawn up lists of diseases which may have pandemic potential; see table below. Coronavirus diseases are a family of usually mild illnesses in humans, including those such as
2090-600: A fast-spreading pandemic may easily exceed and overwhelm existing health-care resources. Consequently, early and aggressive mitigation efforts, aimed at the so-called "epidemic curve flattening" need to be taken. Such measures usually consist on non-pharmacological interventions such as social/physical distancing, aggressive contact tracing, "stay-at-home" orders, as well as appropriate personal protective equipment (i.e., masks, gloves, and other physical barriers to spread). Moreover, India has taken significant strides in its efforts to prepare for future respiratory pandemics through
2200-581: A global emergency. As of 17 August 2024, over 15,600 cases and 537 deaths have been reported in the current outbreak, with approximately 96% of cases occurring in the Democratic Republic of the Congo (DRC). 12 other African countries, some for the first time, have also reported cases. In 2018, an examination of the first four declarations (2009–2016) showed that the WHO was noted to be more effective in responding to international health emergencies, and that
2310-529: A list of diseases that are always notifiable . SARS , smallpox , wild type poliomyelitis , and any new subtype of human influenza are always a PHEIC and do not require an IHR decision to declare them as such. Large scale health emergencies that attract public attention do not necessarily fulfill the criteria to be a PHEIC. ECs were not convened for the cholera outbreak in Haiti , chemical weapons use in Syria , or
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#17328442294392420-475: A million fatalities, and the " Spanish flu " of 1918–1920 eventually infected about one-third of the world's population and caused an estimate 50 million fatalities. The Global Influenza Surveillance and Response System is a global network of laboratories that has for purpose to monitor the spread of influenza with the aim to provide WHO with influenza control information. More than two million respiratory specimens are tested by GISRS annually to monitor
2530-429: A novel influenza virus , WHO previously applied a six-stage classification to delineate the process by which the virus moves from the first few infections in humans through to a pandemic. Starting with phase 1 (infections identified in animals only), it moves through phases of increasing infection and spread to phase 6 (pandemic). In February 2020, a WHO spokesperson clarified that the system is no longer in use. In 2014,
2640-458: A number of ethical and political issues which must be considered during a pandemic. These included decisions about who should be prioritised for treatment while resources are scarce; whether or not to make vaccination compulsory; the timing and extent of constraints on individual liberty, how to sanction individuals who do not comply with emergency regulations, and the extent of international collaboration and resource sharing. The basic strategies in
2750-422: 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 ". The word comes from
2860-780: A pandemic involves many countries so international cooperation, data sharing, and collaboration are essential; as is universal access to tests and therapies. Collaboration - In response to the COVID-19 pandemic, WHO established a Pandemic Hub in September 2021 in Berlin, aiming to address weaknesses around the world in how countries detect, monitor and manage public health threats. The Hub's initiatives include using artificial intelligence to analyse more than 35,000 data feeds for indications of emerging health threats, as well as improving facilities and coordination between academic institutions and WHO member countries. Detection - In May 2023, WHO launched
2970-445: A period of time; an evolutionary change which increases survival time will result in increased virulence. Another possibility, although rare, is that a pathogen may adapt to take advantage of a new mode of transmission Seasonal diseases arise due to the change in the environmental conditions, especially such as humidity and temperature, during different seasons. Many diseases display seasonality , This may be due to one or more of
3080-515: A press conference on 28 December 2020, Mike Ryan, head of the WHO Emergencies Program, and other officials said the current COVID-19 pandemic is "not necessarily the big one" and "the next pandemic may be more severe." They called for preparation. WHO and the UN have warned the world must tackle the cause of pandemics and not just the health and economic symptoms. There is always a possibility that
3190-476: A requirement to submit a draft of this treaty to the 77th World Health Assembly during its 2024 convention. Further, on 6 May 2024, the White House released an official policy to more safely manage medical research projects involving potentially hazardous pathogens , including viruses and bacteria , that may pose a risk of a pandemic. A medical dictionary definition of pandemic is " an epidemic occurring on
3300-486: A rise in cases of wild polio and circulating vaccine-derived poliovirus. The status achieved, as global eradication, was deemed to be at risk by air travel and border crossing overland, with small numbers of cases in Afghanistan, Pakistan, and Nigeria. In October 2019, continuing cases of wild polio in Pakistan and Afghanistan, in addition to new vaccine-derived cases in Africa and Asia, was reviewed and polio continued to be
3410-557: A scale that crosses international boundaries, usually affecting people on a worldwide scale ". 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 contagious —i.e. easily transmissible—and not even simply infectious . This definition differs from colloquial usage in that it encompasses outbreaks of relatively mild diseases. The World Health Organization (WHO) has
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3520-466: A situation that is "serious, sudden, unusual, or unexpected", which may necessitate immediate international action. It can be seen as an "alarm system", a "call to action" and "last resort" measure. WHO Member States have 24 hours within which to report potential PHEIC events to the WHO. It does not have to be a member state that reports a potential outbreak, hence reports to the WHO may also be received informally, by non-governmental sources. Under
3630-487: A type of prevention strategy, holding back diseases such as influenza and polio which have caused pandemics in the past, and could do so again if not controlled. Prevention overlaps with preparedness which aims to curtail an outbreak and prevent it getting out of control - it involves strategic planning, data collection and modelling to measure the spread, stockpiling of therapies, vaccines, and medical equipment, as well as public health awareness campaigning. By definition,
3740-421: A very rare disease may be classified as an epidemic, while many cases of a common disease (such as the common cold ) would not. An epidemic can cause enormous damage through financial and economic losses in addition to impaired health and loss of life. The United States Centers for Disease Control and Prevention defines epidemic broadly: "Epidemic refers to an increase, often sudden, in the number of cases of
3850-503: A word form attributed to Homer 's Odyssey , which later took its medical meaning from the Epidemics , a treatise by Hippocrates . Before Hippocrates, epidemios , epidemeo , epidamos , and other variants had meanings similar to the current definitions of " indigenous " or " endemic ". Thucydides ' description of the Plague of Athens is considered one of the earliest accounts of
3960-427: Is a disease surveillance system. Tanzania , for example, runs a national lab that runs testing for 200 health sites and tracks the spread of infectious diseases. The next layer is the actual response to an emergency. According to U.S.-based columnist Michael Gerson in 2015, only the U.S. military and NATO have the global capability to respond to such an emergency. Still, despite the most extensive preparatory measures,
4070-478: Is a formal declaration by the World Health Organization (WHO) of "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", formulated when a situation arises that is "serious, sudden, unusual, or unexpected", which "carries implications for public health beyond
4180-713: Is abrupt - in this, two or more different strains of a virus , coinfecting a single host, combine to form a new subtype having a mixture of characteristics of the original strains. The best known and best documented example of both processes is influenza . SARS-CoV2 has demonstrated antigenic drift and possibly shift as well. Antibiotic resistance applies specifically to bacteria that become resistant to antibiotics . Resistance in bacteria can arise naturally by genetic mutation , or by one species acquiring resistance from another through horizontal gene transfer . Extended use of antibiotics appears to encourage selection for mutations which can render antibiotics ineffective. This
4290-509: Is an incomplete list of known epidemics which spread widely enough to merit the title "pandemic". Beginning from the Middle Ages, encounters between European settlers and native populations in the rest of the world often introduced epidemics of extraordinary virulence. Settlers introduced novel diseases which were endemic in Europe, such as smallpox , measles , pertussis .and influenza , to which
4400-425: Is by means of a HIV test. There is no vaccine to prevent HIV infection, but the disease can be held in check by means of antiretroviral therapy . Historical accounts of epidemics are often vague or contradictory in describing how victims were affected. A rash accompanied by a fever might be smallpox, measles, scarlet fever, or varicella , and it is possible that epidemics overlapped, with multiple infections striking
4510-494: Is considered an epidemic. Epidemics of infectious disease are generally caused by several factors including a change in the ecology of the host population (e.g., increased stress or increase in the density of a vector species), a genetic change in the pathogen reservoir or the introduction of an emerging pathogen to a host population (by movement of pathogen or host). Generally, an epidemic occurs when host immunity to either an established pathogen or newly emerging novel pathogen
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4620-668: Is developing a program to condense new vaccine development timelines to 100 days, a third of the time it took to develop a COVID-19 vaccine. CEPI aims to reduce global epidemic and pandemic risk by developing vaccines against known pathogens as well as enabling rapid response to Disease X . In the US, the National Institute of Allergy and Infectious Diseases (NIAID) has developed a Pandemic Preparedness Plan which focuses on identifying viruses of concern and developing diagnostics and therapies (including prototype vaccines) to combat them. Modeling
4730-421: Is especially true of tuberculosis , with increasing occurrence of multiple drug-resistant tuberculosis (MDR-TB) worldwide. Pathogen transmission is a term used to describe the mechanisms by which a disease-causing agent (virus, bacterium, or parasite) spreads from one host to another. Common modes of transmission include: - The first three of these require that pathogen must survive away from its host for
4840-709: Is important to inform policy decisions. It helps to predict the burden of disease on healthcare facilities, the effectiveness of control measures, projected geographical spread, and timing and extent of future pandemic waves. Public Awareness involves disseminating reliable information, ensuring consistency on message, transparency, and steps to discredit misinformation . Stockpiling involves maintaining strategic stockpiles of emergency supplies such as personal protective equipment, drugs and vaccines, and equipment such as respirators. Many of these items have limited shelf life , so they require stock rotation even though they may be rarely used. The COVID-19 pandemic highlighted
4950-439: Is no longer possible to contain the spread of the disease, management will then move on to the mitigation stage, in which measures are taken to slow the spread of the disease and mitigate its effects on society and the healthcare system. In reality, containment and mitigation measures may be undertaken simultaneously. A key part of managing an infectious disease outbreak is trying to decrease the epidemic peak, known as " flattening
5060-400: Is not immune. An example of this was the introduction European diseases such as smallpox into indigenous populations during the 16th century. A zoonosis is an infectious disease of humans caused by a pathogen that can jump from a non-human host to a human. Major diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in
5170-415: Is not only confined to infectious diseases, and may cover an emergency caused by exposure to a chemical agent or radioactive material. It can be seen as an "alarm system", a "call to action", and "last resort" measure. Multiple surveillance and response systems exist worldwide for the early detection and effective response to contain the spread of disease. Time delays occur for two main reasons. The first
5280-550: Is suddenly reduced below that found in the endemic equilibrium and the transmission threshold is exceeded. An epidemic may be restricted to one location; however, if it spreads to other countries or continents and affects a substantial number of people, it may be termed as a pandemic . The declaration of an epidemic usually requires a good understanding of a baseline rate of incidence ; epidemics for certain diseases, such as influenza , are defined as reaching some defined increase in incidence above this baseline. A few cases of
5390-417: Is technically preferable. There are several factors that may contribute (individually or in combination) to causing an epidemic. There may be changes in a pathogen , in the population that it can infect, in the environment, or in the interaction between all three. Factors include the following: An antigen is a protein on the virus ' surface that host antibodies can recognize and attack. Changes in
5500-444: Is the delay between the first case and the confirmation of the outbreak by the healthcare system, allayed by good surveillance via data collection, evaluation, and organisation. The second is when there is a delay between the detection of the outbreak and widespread recognition and declaration of it as an international concern. The declaration is promulgated by an emergency committee (EC) made up of international experts operating under
5610-703: The 2009–2010 H1N1 (or swine flu) pandemic , the ongoing 2014 polio declaration , the 2013–2016 outbreak of Ebola in Western Africa , the 2015–16 Zika virus epidemic , the 2018–2020 Kivu Ebola epidemic , the 2020–2023 declaration for the COVID-19 pandemic , and the 2022–2023 and 2024 mpox outbreaks . The recommendations are temporary and require reviews every three months. Automatically, SARS , smallpox , wild type poliomyelitis , and any new subtype of human influenza are considered as PHEICs and thus do not require an IHR decision to declare them as such. A PHEIC
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#17328442294395720-518: The Australian Aboriginal population, killing an estimated 50% of those infected with the disease during the first decades of colonisation. In the early 1800s, measles, smallpox and intertribal warfare killed an estimated 20,000 New Zealand Māori . In 1848–49, as many as 40,000 out of 150,000 Hawaiians are estimated to have died of measles , whooping cough and influenza . Measles killed more than 40,000 Fijians , approximately one-third of
5830-613: The Fukushima nuclear disaster in Japan , for example. Further assessment is required for diseases that are prone to becoming pandemics , including, but not limited to cholera , pneumonic plague , yellow fever , and viral hemorrhagic fevers. A declaration of a PHEIC may appear as an economic burden to the state facing the epidemic. Incentives to declare an epidemic are lacking and the PHEIC may be seen as placing limitations on trade in countries that already are struggling. In order to declare
5940-554: The Greek παν- pan- meaning "all", or "every" and δῆμος demos "people". A common early characteristic of a pandemic is a rapid, sometimes exponential , growth in the number of infections, coupled with a widening geographical spread. WHO utilises different criteria to declare a Public Health Emergency of International Concern (PHEIC), its nearest equivalent to the term pandemic. The potential consequences of an incident are considered, rather than its current status. For example, polio
6050-476: The Lancet commission on COVID-19 published a report, calling the response to the pandemic "a massive global failure on multiple levels". The WHO responded by noting "several key omissions and misinterpretations in the report, not least regarding the public health emergency of international concern (PHEIC) and the speed and scope of WHO's actions." They stated that the report "offers the best opportunity to insist that
6160-575: The Spanish flu —which is the deadliest pandemic in history . The most recent pandemics include the HIV/AIDS pandemic , the 2009 swine flu pandemic and the COVID-19 pandemic . Almost all these diseases still circulate among humans though their impact now is often far less. In response to the COVID-19 pandemic, 194 member states of the World Health Organization began negotiations on an International Treaty on Pandemic Prevention, Preparedness and Response , with
6270-574: The United Nations ' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services , written by 22 experts in a variety of fields, said the anthropogenic destruction of biodiversity is paving the way to the pandemic era and could result in as many as 850,000 viruses being transmitted from animals—in particular birds and mammals —to humans. The "exponential rise" in consumption and trade of commodities such as meat , palm oil , and metals, largely facilitated by developed nations, and
6380-506: The United States and the world . On 26 April 2009, more than one month after its first emergence, the initial PHEIC was declared when the H1N1 (or swine flu) pandemic was still in phase three . Within three hours on the same day, the WHO web site received almost two million visits, necessitating a dedicated web site for the swine influenza pandemic. At the time that H1N1 had been declared
6490-463: The antigenic characteristics of the agent make it easier for the changed virus to spread throughout a previously immune population. There are two natural mechanisms for change - antigenic drift and antigenic shift . Antigenic drift arises over a period of time as an accumulation of mutations in the virus genes , possibly through a series of hosts, and eventually gives rise to a new strain of virus which can evade existing immunity. Antigenic shift
6600-517: The common cold , that have resulted in outbreaks and pandemics such as the 1889-1890 pandemic , the 2002–2004 SARS outbreak , Middle East respiratory syndrome–related coronavirus and the COVID-19 pandemic . There is widespread concern that members of the coronavirus family, particularly SARS and MERS have the potential to cause future pandemics. Many human coronaviruses have zoonotic origin, their with natural reservoir in bats or rodents, leading to concerns for future spillover events. Following
6710-686: The indigenous peoples had no immunity. The Europeans infected with such diseases typically carried them in a dormant state , were actively infected but asymptomatic , or had only mild symptoms. Smallpox was the most destructive disease that was brought by Europeans to the Native Americans, both in terms of morbidity and mortality. The first well-documented smallpox epidemic in the Americas began in Hispaniola in late 1518 and soon spread to Mexico. Estimates of mortality range from one-quarter to one-half of
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#17328442294396820-431: The 2005 International Health Regulations (IHR), states have a legal duty to respond promptly to a PHEIC. PHEIC is 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. This definition designates a public health crisis of potentially global reach and implies
6930-413: The DRC, together with an expert committee led by a virologist, took responsibility for directly supervising action, while in protest of the declaration health minister Oly Ilunga Kalenga resigned. A review of the PHEIC had been planned at a fifth meeting of the EC on 10 October 2019 and on 18 October 2019 it remained a PHEIC until 26 June 2020 when it was decided that the situation no longer constituted
7040-568: The IHR (2005), which was developed following the SARS outbreak of 2002–2003. Between 2009 and 2016, there were four PHEIC declarations. The fifth was the 2018–2020 Kivu Ebola epidemic , declared in July 2019 and ended in June 2020. The sixth was the COVID-19 pandemic , declared in January 2020 and ended in May 2023. The seventh was the 2022–2023 mpox outbreak , declared in July 2022 and ended in May 2023. Under
7150-436: The IHR (2005), ways to detect, evaluate, notify, and report events were ascertained by all countries in order to avoid PHEICs. The response to public health risks also was decided. The IHR decision algorithm assists WHO Member States in deciding whether a potential PHEIC exists and whether the WHO should be notified. The WHO should be notified if any two of the four following questions are affirmed: The PHEIC criteria include
7260-481: The International Health Regulations as well as a new legally binding agreement (most likely a treaty) on pandemic prevention, preparedness, and response. Proposals include the possibility of issuing intermediate public health alerts (short of PHEICs) and determining public health emergencies of regional concern. Notably, although COVID-19 is routinely referred to as a pandemic, this word is not used in
7370-424: The International Health Regulations." With the emergency phase of the pandemic being regarded as having ended, more subtle and robust institutional responses and protocols are in the works for further iterations of this pandemic as well as global pandemics of whatever etiology . At the second IHR meeting for the 2022–2023 mpox outbreak on 21 July 2022, members of the emergency committee were divided about issuing
7480-597: The International Pathogen Surveillance Network (IPSN) (hosted by the Pandemic Hub) aiming to detect and respond to disease threats before they become epidemics and pandemics, and to optimize routine disease surveillance. The network provides a platform to connect countries, improving systems for collecting and analysing samples of potentially harmful pathogens . Therapies and Vaccines - The Coalition for Epidemic Preparedness Innovations (CEPI)
7590-763: The United States Centers for Disease Control and Prevention (CDC) introduced a framework for characterising the progress of an influenza pandemic titled the Pandemic Intervals Framework . The six intervals of the framework are as follows: At the same time, the CDC adopted the Pandemic Severity Assessment Framework (PSAF) to assess the severity of influenza pandemics. The PSAF rates the severity of an influenza outbreak on two dimensions: clinical severity of illness in infected persons; and
7700-514: The WHO declared its fourth PHEIC in response to clusters of microcephaly and Guillain–Barré syndrome in the Americas , which at the time were suspected to be associated with the ongoing 2015–16 Zika virus epidemic . Later research and evidence bore out these concerns; in April, the WHO stated that "there is scientific consensus that Zika virus is a cause of microcephaly and Guillain–Barré syndrome." This
7810-474: The absence of a trajectory toward extinguishing the outbreak, the opposite path—severe escalation—remains possible. The risk of the disease moving into nearby Goma, Congo—a city of 1 million residents with an international airport—or crossing into the massive refugee camps in South Sudan is mounting. With a limited number of vaccine doses remaining, either would be a catastrophe". Four days later, on 14 July 2019,
7920-415: The affected state's national border" and "may require immediate international action". Under the 2005 International Health Regulations (IHR), states have a legal duty to respond promptly to a PHEIC. The declaration is publicized by an IHR Emergency Committee (EC) of international experts, which was developed following the 2002–2004 SARS outbreak . Since 2005, there have been eight PHEIC declarations:
8030-439: The control of an outbreak are containment and mitigation . Containment may be undertaken in the early stages of the outbreak, including contact tracing and isolating infected individuals to stop the disease from spreading to the rest of the population, other public health interventions on infection control, and therapeutic countermeasures such as vaccinations which may be effective if available. When it becomes apparent that it
8140-729: The curve ". This helps decrease the risk of health services being overwhelmed and provides more time for a vaccine and treatment to be developed. A broad group of non-pharmaceutical interventions may be taken to manage the outbreak. In a flu pandemic, these actions may include personal preventive measures such as hand hygiene, wearing face-masks, and self-quarantine; community measures aimed at social distancing such as closing schools and canceling mass gatherings; community engagement to encourage acceptance and participation in such interventions; and environmental measures such as cleaning of surfaces. Another strategy, suppression , requires more extreme long-term non-pharmaceutical interventions to reverse
8250-599: The development of the National Pandemic Preparedness Plan for Respiratory Viruses using a multisectoral approach. Preceding this national effort, a regional workshop on the Preparedness and Resilience for Emerging Threats (PRET) initiative was organized by WHO's South-East Asia Regional Office on October 12-13, 2023. Recognizing that the same capacities and capabilities can be leveraged and applied for groups of pathogens based on their mode of transmission,
8360-638: The diseases become accepted into people's daily lives and routines, becoming endemic . The transition from pandemic to endemic may be defined based on: 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. Pandemic prevention comprises activities such as anticipatory research and development of therapies and vaccines, as well as monitoring for pathogens and disease outbreaks which may have pandemic potential. Routine vaccination programs are
8470-400: The distribution of these diseases due to the changing geographic range of their vectors, with the potential to cause serious outbreaks in areas where the disease has not previously been known. The other group comprises water-borne diseases such as cholera, dysentery, and typhoid which may increase in prevalence due to changes in rainfall patterns. The October 2020 'era of pandemics' report by
8580-408: The early part of the 20th century, though it has now evolved into a separate human-only disease. Some strains of bird flu and swine flu are zoonoses; these viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu . In a common source outbreak epidemic, the affected individuals had an exposure to a common agent. If
8690-709: The emergencies did not coincide with holidays. PHEIC was not invoked with the Middle Eastern Respiratory Syndrome (MERS) outbreak in 2013. Originating in Saudi Arabia, MERS reached more than 24 countries and resulted in 876 deaths by May 2020, although most cases were in hospital settings rather than sustained community spread. As a result, what constitutes a PHEIC has been unclear. PHEIC are not confined to only infectious diseases or biological ones. It may cover events caused by chemical agents or radioactive materials. Debate exists regarding whether
8800-493: The end of the COVID-19 pandemic Public Health Emergency of International Concern deceleration by WHO, WHO Director General Tedros Ghebreyesus stated he would not hesitate to re-declare COVID-19 a PHEIC should the global situation worsen in the coming months or years. Influenza was first described by the Greek physician Hippocrates in 412 BC. Since the Middle Ages, influenza pandemics have been recorded every 10 to 30 years as
8910-470: The event. Upon declaration, the EC then makes recommendations on what actions the director-general and member states should take to address the crisis. The recommendations are temporary and require review every three months while in place. Summary of PHEIC declarations In the spring of 2009, a novel influenza A (H1N1) virus emerged. It was detected first in Mexico , North America . It spread quickly across
9020-650: The exposure is singular and all of the affected individuals develop the disease over a single exposure and incubation course, it can be termed as a point source outbreak. If the exposure was continuous or variable, it can be termed as a continuous outbreak or intermittent outbreak, respectively. In a propagated outbreak, the disease spreads person-to-person. Affected individuals may become independent reservoirs leading to further exposures. Many epidemics will have characteristics of both common source and propagated outbreaks (sometimes referred to as mixed outbreak ). For example, secondary person-to-person spread may occur after
9130-468: The failures and lessons from the past 3 years are not wasted but are constructively used to build more resilient health systems and stronger political systems that support the health and wellbeing of people and planet during the 21st century." The formal end of the COVID-19 PHEIC is a matter of much nuance which carries its own risks, and as of March 2023, "WHO member states are negotiating amendments to
9240-403: The following underlying factors: - Changes in behaviour can affect the likelihood or severity of epidemics. The classic example is the 1854 Broad Street cholera outbreak , in which a cholera outbreak was mitigated by removing a supply of contaminated water - an event now regarded as the foundation of the science of epidemiology . Urbanisation and overcrowding (e.g. in refugee camps ) increase
9350-404: The following years, immunity will decline, both within individuals and in the population as a whole as older individuals die and new individuals are born. Eventually, unless there is another vaccination campaign, an outbreak or epidemic will recur. It's also possible for disease which is endemic in one population to become epidemic if it is introduced into a novel setting where the host population
9460-417: The globe rather than being spread worldwide. Throughout human history , there have been a number of pandemics of diseases such as smallpox . The Black Death , caused by the Plague , caused the deaths of up to half of the population of Europe in the 14th century. The term pandemic had not been used then, but was used for later epidemics, including the 1918 H1N1 influenza A pandemic—more commonly known as
9570-441: The human population. For example, influenza is a rapidly evolving disease which has caused pandemics in the past and has potential to cause future pandemics. WHO collates the findings of 144 national influenza centres worldwide which monitor emerging flu viruses. Virus variants which are assessed as likely to represent a significant risk are identified and can then be incorporated into the next seasonal influenza vaccine program. In
9680-410: The international system in dealing with these emergencies was "robust". Another review of the first four declarations, with the exception of wild polio, demonstrated that responses were varied. Severe outbreaks, or those that threatened larger numbers of people, did not receive a swift PHEIC declaration, and the study hypothesized that responses were quicker when American citizens were infected and when
9790-415: The likelihood of disease outbreaks. A factor which contributed to the initial rapid increase in the 2014 Ebola virus epidemic was ritual bathing of (infective) corpses; one of the control measures was an education campaign to change behaviour around funeral rites. The level of immunity to a disease in a population - herd immunity - is at its peak after a disease outbreak or a vaccination campaign. In
9900-485: The names of IHR EC members were not publicly disclosed; in the wake of reforms, now they are. These members are selected according to the disease in question and the nature of the event. Names are taken from the IHR Experts Roster . The director-general takes the advice of the EC, following their technical assessment of the crisis using legal criteria and a predetermined algorithm after a review of all available data on
10010-471: The occurrence of Ebola in the United States and Europe and with the already intense transmission ongoing in three other countries for months, the WHO declared its third PHEIC in response to the outbreak of Ebola in Western Africa . Later, one review showed that a direct impact of this epidemic on America escalated a PHEIC declaration. It was the first PHEIC in a resource-poor setting. On 1 February 2016,
10120-665: The outbreak, but it was determined at that time that it was too early to declare a PHEIC, given the lack of necessary data and the then-scale of global impact. The WHO recognized the spread of COVID-19 as a pandemic on 11 March 2020. The emergency committee convened its third meeting on 30 April 2020, fourth on 31 July, fifth on 29 October, sixth on 14 January 2021, seventh on 15 April 2021, ninth in October 2021, tenth in January 2022, eleventh in April 2022, twelfth in July 2022, thirteenth in October 2022, fourteenth in January 2023, and fifteenth in May 2023. In September 2022,
10230-471: The outbreak, which had more than 2,100 cases in over 42 countries at that point; it did not reach the criteria for a PHEIC alert at the time. It was re-classified a PHEIC in August 2024. After an IHR meeting on 14 August 2024, the WHO declared an mpox outbreak in parts of Africa , of a new variant of the disease, a PHEIC. This marks the second time in three years that the WHO has classified an mpox outbreak as
10340-401: The pandemic by reducing the basic reproduction number to less than 1. The suppression strategy, which includes stringent population-wide social distancing, home isolation of cases, and household quarantine, was undertaken by China during the COVID-19 pandemic where entire cities were placed under lockdown; such a strategy may carry with it considerable social and economic costs. For
10450-453: The population of central Mexico. It is estimated that over the 100 years after European arrival in 1492, the indigenous population of the Americas dropped from 60 million to only 6 million, due to a combination of disease, war, and famine. The majority these deaths are attributed to successive waves of introduced diseases such as smallpox, measles, and typhoid fever. In Australia , smallpox was introduced by European settlers in 1789 devastating
10560-466: The population, in 1875, and in the early 19th century devastated the Great Andamanese population. In Hokkaido , an epidemic of smallpox introduced by Japanese settlers is estimated to have killed 34% of the native Ainu population in 1845. Prevention of future pandemics requires steps to identify future causes of pandemics and to take preventive measures before the disease moves uncontrollably into
10670-468: The possibility of zoonotic infections. The advent of agriculture, and trade between settled groups, made it possible for pathogens to spread widely. As population increased, contact between groups became more frequent. A history of epidemics maintained by the Chinese Empire from 243 B.C. to 1911 A.C. shows an approximate correlation between the frequency of epidemics and the growth of the population. Here
10780-533: The primary cause of pandemics so far, the anthropogenic destruction of the natural world through such activities including deforestation and hunting , is being ignored by world leaders. Epidemic An epidemic (from Greek ἐπί epi "upon or above" and δῆμος demos "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infections , an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks
10890-552: The report include taxing meat production and consumption, cracking down on the illegal wildlife trade, removing high-risk species from the legal wildlife trade, eliminating subsidies to businesses that are harmful to the natural world, and establishing a global surveillance network. In June 2021, a team of scientists assembled by the Harvard Medical School Center for Health and the Global Environment warned that
11000-485: The same population at once. It is often impossible to know the exact causes of mortality, although ancient DNA studies can sometimes detect residues of certain pathogens. It is assumed that, prior to the Neolithic Revolution around 10,000 BC, disease outbreaks were limited to a single family or clan, and did not spread widely before dying out. The domestication of animals increased human-animal contact, increasing
11110-484: The situation as "an Ebola gas can sitting in DRC that's just waiting for a match to hit it", while the WHO panel were unanimous in their decision that declaring it a PHEIC would not give any added benefit. The advice against declaring a PHEIC in October 2018 and April 2019, despite the criteria for doing so appearing to be met on both occasions, has led to the transparency of the IHR EC coming into question. The language used in
11220-447: The spread and evolution of influenza viruses through a network of about 150 laboratories in 114 countries representing 91% of the world's population. Antibiotic-resistant microorganisms, which sometimes are referred to as " superbugs ", may contribute to the re-emergence of diseases with pandemic potential that are currently well controlled. For example, cases of tuberculosis that are resistant to traditionally effective treatments remain
11330-458: The statements for the Kivu Ebola epidemic has been noted to be different. In October 2018, the EC stated "a PHEIC should not be declared at this time". In the 13 previously declined proposals for declaring a PHEIC, the resultant statements quoted "the conditions for a PHEIC are not currently met" and "does not constitute a PHEIC". In April 2019, they stated that "there is no added benefit to declaring
11440-474: The transmissibility of the infection in the population. This tool was not applied during the COVID-19 pandemic. SARS-CoV-2 , a new strain of coronavirus , was first detected in the city of Wuhan, Hubei Province , China, in December 2019. The outbreak was characterized as a Public Health Emergency of International Concern (PHEIC) between January 2020 and May 2023 by WHO. The number of people infected with COVID-19 has reached more than 767 million worldwide, with
11550-413: The virus mutates to evade immunity. Influenza is an endemic disease , with a fairly constant number of cases which vary seasonally and can, to a certain extent, be predicted. In a typical year, 5–15% of the population contracts influenza. There are 3–5 million severe cases annually, with up to 650,000 respiratory-related deaths globally each year. The 1889–1890 pandemic is estimated to have caused around
11660-462: The workshop aimed to facilitate pandemic planning efficiency for countries in the region. The participating countries, in the aftermath of the workshop, outlined their immediate next steps and sought support from WHO and its partners to bolster regional preparedness against respiratory pathogen pandemics. Public health emergency of international concern A public health emergency of international concern ( PHEIC / f eɪ k / FAYK )
11770-460: Was declared a PHEIC in 2014 even though only 482 cases were reported globally in the previous year; this was justified by concerns that polio might break out of its endemic areas and again become a significant health threat globally. The PHEIC status of polio is reviewed regularly and is ongoing, despite the small number of cases annually. The end of a pandemic is more difficult to delineate. Generally, past epidemics & pandemics have faded out as
11880-425: Was a health emergency in the Democratic Republic of the Congo (DRC) and the region, it did not meet all the three criteria for a PHEIC. Despite the number of deaths reaching 1,405 by 11 June 2019 and 1,440 by 17 June 2019, the reason for not declaring a PHEIC was that the overall risk of international spread was deemed to be low, and the risk of damaging the economy of the DRC high. Adhanom also stated that declaring
11990-810: Was first identified in Africa in 2006 and subsequently discovered to exist in 49 countries. During 2021 there were estimated to be around 25,000 cases XDR-TB worldwide. In the past 20 years, other common bacteria including Staphylococcus aureus , Serratia marcescens and Enterococcus , have developed resistance to a wide range of antibiotics . Antibiotic-resistant organisms have become an important cause of healthcare-associated ( nosocomial ) infections. There are two groups of infectious disease that may be affected by climate change. The first group are vector-borne diseases which are transmitted via insects such as mosquitos or ticks. Some of these diseases, such as malaria , yellow fever , and dengue fever , can have potentially severe health consequences. Climate can affect
12100-477: Was the first time a PHEIC was declared for a mosquito‐borne disease . This declaration was lifted on 18 November 2016. In October 2018 and then later in April 2019, the WHO did not consider the 2018–2020 Kivu Ebola epidemic to be a PHEIC. The decision was controversial, with Michael Osterholm , director of the Center for Infectious Disease Research and Policy (CIDRAP) responding with disappointment and describing
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