As coronavirus spreads around the world, the World Health Organisation (WHO) has declared the virus a pandemic.
Definitions of the emotionally charged words ‘outbreak’, ‘epidemic’ and ‘pandemic’ can be blurred during viral outbreaks. So what do they each mean?
An outbreak is the initial stage classification of a disease affecting numerous people. The term refers to a sudden rise in the number of cases of a disease. Outbreaks can affect single communities or several countries but is typically small-scale or low risk.
The influenza exhibits seasonal yearly outbreaks across multiple countries. Influenza is typically not considered an epidemic or pandemic because influenza vaccinations minimise risk.
An outbreak is considered an epidemic when an infectious disease is spread rapidly to many people. An epidemic is geographically limited to a population.
Epidemics typically occur when host immunity to either an established disease or virus is reduced, or a novel pathogen is introduced to a population. Low immunity allows the rapid spread of a virus across populations.
A pandemic is the worldwide spread of a new disease. The word refers to when an epidemic spreads globally. There is no clear point in which an epidemic is considered a pandemic. By definition, as soon as an epidemic crosses borders, it becomes a pandemic. However, it typically takes longer for an epidemic to be considered a pandemic. Because the emotional implications of pandemics have spark anxieties in populations and the classification has global implications on the approach to a crisis, officials are typically hesitant to increase a crisis from epidemic.
A pandemic sees more governments becoming involved in the preventing the virus spread and researching treatment and vaccinations. Pandemics significantly impact global travel, stock markets and the global economy.
Does labelling matter?
An outbreak changing classifications from epidemic to pandemic has implications on the approach to the health crisis.
The geographic limitations of an epidemic allow organisations and health agencies such as the WHO to intervene to slow or prevent spread of the virus. A pandemic has consequences for how many resources such as people, money or supplies are available to address the outbreak and where they are placed. During a pandemic, the WHO and United Nations divide resources across the world rather than an affected territory.
Governments focus on preventing the spread of the virus during an epidemic. A pandemic will cause authorities to stop prevention and focus on treating the illness and protecting the vulnerable.