Coronavirus: WHO declares the outbreak 'pandemic', what's the difference with epidemic

The World Health Organisation on Wednesday declared the novel coronavirus, or COVID-19, outbreak as a pandemic, months after the virus spread from China's Wuhan. Over one lakh twenty thousand people have been tested positive for the virus and at least 4,000 people have died. The virus has spread to nearly 120 countries and so far, 67 cases have been reported in India.

The virus was already classified as an epidemic in China. But now that the classification has changed, here's a look into what differentiates epidemic from pandemic.

Following the outbreak of coronavirus in central China's metropolis of Wuhan in late December last year, authorities there scrambled resources to contain the spread. The entire province of Hubei, of which Wuhan is the capital, was under a tight lockdown for over a month. The mobility of people was restricted across China as an immediate response. WHO declared a Public Health Emergency of International Concern on January 30.

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What is an epidemic?

A disease is categorised as an epidemic when cases of the disease are reported "in excess of normal expectancy". An epidemic is an outbreak over a larger geographic area. So when coronavirus spread outside Wuhan and number of cases from other parts of China began breaking records by the day, epidemiologists knew the outbreak was spreading, a likely sign that containment efforts were insufficient or came too late.

The conclusion was expected as no cure or vaccine was available. Widespread cases of COVID-19 across China meant that the Wuhan outbreak had grown to an epidemic. 

According to the Centre for Disease Control (CDC), an epidemic may result from:

• A recent increase in amount or virulence of the agent (virus, bacteria),
• The recent introduction of the agent into a setting where it has not been before,
• An enhanced mode of transmission so that more susceptible persons are exposed,
• A change in the susceptibility of the host response to the agent, and/or
• Factors that increase host exposure or involve introduction through new portals of entry.

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What is a pandemic?

Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people. It basically means that there is a simultaneous and sustained spread of a disease across the world, across international borders. 

To set in clear terms, a person infected with COVID-19 who returns to India from China doesn’t make a pandemic. But once they infect a few family members or friends and the cycle continues to infect more and more people in a community and raises the toll of infection cases, then it becomes a major health problem. If new local outbreaks ensue, epidemiologists will agree that efforts to control global spread have failed and refer to the emerging situation as a pandemic.

Speaking to reporters in Geneva, WHO Director-General Dr. Tedros Adhanom Ghebreyesus warned of a further rise in the number of cases, fatality and the number of affected countries. “In the days and weeks ahead, we expect to see the number of cases, the number of deaths and the number of affected countries to climb even higher.”

The last time WHO declared a pandemic was during the 2009 H1N1 swine flu outbreak. Tedros said COVID-19 is the first time a coronavirus has caused a pandemic. The 2002-2003 outbreak of SARS, which is also a coronavirus, was contained enough to avoid that classification.

WHO's clear message to the world

The WHO chief said several countries like China and South Korea have been able to suppress and control COVID-19 outbreak, but he scolded other world leaders for failing to act quickly or drastically enough to contain the spread.

“We’re deeply concerned, both by the alarming levels of spread and severity, and by the alarming levels of inaction. We have rung the alarm bell loud and clear,” Tedros said.

That means the WHO wants governments across the world to take more urgent steps to arrest further worsening of the situation. It has already pressed countries to pledge more funds to fight the disease and undertake precautionary measures in those nations who haven't yet reported cases.

(With inputs from agencies) (AP photo)

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