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Member Research & Reports

Member Research & Reports

Texas A&M: What’s The Difference Between a Pandemic, Epidemic and Outbreak?

The difference between an outbreak, epidemic and pandemic is a matter of scale, says Dr. Rebecca Fischer, of the Texas A&M School of Public Health. The World Health Organization (WHO) has declared COVID-19 a pandemic. This is a landmark event.

An outbreak is a noticeable, often small, increase over the expected number of cases. An example is the cluster of pneumonia cases that sprung up unexpectedly among market-goers in Wuhan, China. Public health officials now know the spike in pneumonia cases there constituted an outbreak of a new type of coronavirus, now named SARS-CoV-2.

An epidemic is an outbreak over a larger geographic area. When people in places outside of Wuhan began testing positive for infection with SARS-CoV-2 (which causes the disease known as COVID-19), epidemiologists knew the outbreak was spreading, a likely sign that containment efforts were insufficient or came too late.

In the most classical sense, once an epidemic spreads to multiple countries or regions of the world, it is considered a pandemic. However, some epidemiologists classify a situation as a pandemic only once the disease is sustained in some of the newly affected regions through local transmission.

Epidemiologists are principally concerned with preventing disease, which may be fundamentally different than the broader concerns of governments or international health organizations.

The formal declaration of COVID-19 or any other infectious disease as pandemic tells governments, agencies and aid organizations worldwide to shift efforts from containment to mitigation. It has economic, political and societal impacts on a global scale, and the WHO takes extreme care when making this determination.

The complete article published in The Conversation.

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