What is a pandemic?
Pandemics have nothing to do with the severity of a disease but are to do with its geographic spread. According to the World Health Organization, a pandemic is declared when a new disease for which people do not have immunity spreads around the world beyond expectations.
Cases that involve travellers who have been infected in China and have then returned to their home country, or who have been infected by that traveller, known as the “index case”, do not count towards declaring a pandemic. There needs to be a second wave of infection from person to person throughout the community. In the US, the UK and Australia, there is no active community transmission at present.
Once a pandemic is declared, it becomes more likely that community spread will eventually happen, and governments and health systems need to ensure they are prepared for that.
An epidemic, on the other hand, is a sudden increase in cases of an illness or disease that can be unique to one country or community.
When is a pandemic declared?
Prof Mary-Louise McLaws, an infection control expert who has worked as an adviser to WHO, said declaring a pandemic was not always clear-cut because it could depend on the modelling used, which may differ between the WHO and other health organisations. Ultimately, the WHO gets the final say. There is no threshold, such as a certain number of deaths or infections, or number of countries affected, that needs to be met. For example, the Sars coronavirus, identified in 2003, was not declared a pandemic by the WHO despite affecting 26 countries. However its spread was contained quickly, and only a handful of nations were significantly affected, including China, Hong Kong, Taiwan, Singapore and Canada.
“WHO do things for lots of reasons but part of the reason for declaring a pandemic, if they do declare one, would be to get the critical mass on board to take it seriously and not ignore symptoms, and to get the finances required to help tackle and control it,” McLaws said.
However, if declaring a pandemic triggers global panic, this can defeat the purpose of trying to raise awareness. Much has been written about whether the declaration of H1N1, colloquially known as “swine flu”, as a pandemic in 2009, caused unnecessary panic, overwhelming emergency departments and causing governments to overspend on antiviral medications. Coronavirus symptoms are generally mild and most people recover within six days.
Infectious diseases expert Prof Peter Collignon said it appeared that the fecal-oral route may be an important part of coronavirus transmission. In countries with strong water sanitation and a safe and reliable water supply, the impact of a pandemic could be less severe.
If WHO declares a coronavirus pandemic what will it mean for the way an outbreak is treated and prepared for?
Currently there is local spread of coronavirus in China, South Korea, Japan, Iran, Italy and Singapore.
The director of infectious diseases and immunology at the Menzies Health Institute in Queensland Prof Nigel McMillan, said it was concerning to see media reports over-sensationalising what a pandemic might mean.
“We don’t wish to induce panic food or petrol stockpiling, when for 95% of the population, this will be a mild cold,” he said.
But a pandemic would mean travel bans would no longer be useful or make sense and would alert health authorities that they need to prepare for the next phase.
“This includes preparing our hospitals for a large influx of patients, stockpiling any antivirals, and advising the public that when the time comes ,they will need to think about things like staying at home if ill, social distancing, avoiding large gatherings etc,” McMillan said.
McLaws said this might prove the toughest part for governments – encouraging people to change their behaviours, such as forgoing or cancelling large social events if they are sick. In response to the Severe Acute Respiratory Syndrome (Sars) outbreak 17 years ago, McLaws collaborated with Beijing to review the reasons for healthcare workers acquiring Sars.
“What those health workers saw, and the way they saw their colleagues get sick, meant they cooperated with the government to contain the spread,” she said.
“Countries used to a good level of health in their population may need to work harder to get their citizens ready.”
Experts say a vaccine is approximately 18 months away.
What are other examples of pandemics?
The 2009 H1N1 outbreak, HIV (1981), Spanish flu (1918), bubonic plague (1347) and smallpox (1870) are all examples of pandemics.
