01 global pandemic
What are pandemics? Can they be stopped?
02:55 - Source: CNN
CNN  — 

The deadly novel coronavirus outbreak has turned a spotlight on the science of disease, raising the question: What exactly is a pandemic?

An outbreak is the occurrence of disease cases in excess of what’s normally expected, according to the World Health Organization. An epidemic is more than a normal number cases of an illness, specific health-related behavior or other health-related events in a community or region.

Yet a pandemic is defined as the “worldwide spread” of a new disease.

The last pandemic reported in the world was the H1N1 flu pandemic in 2009, which killed hundreds of thousands globally.

The word “pandemic comes from the Greek ‘pandemos,’ which means everybody. Demos means the population. Pan meaning everyone. So ‘pandemos’ is a concept where there’s a belief that the whole world’s population will likely be exposed to this infection and potentially a proportion of them fall sick,” Dr. Mike Ryan, WHO executive director of the agency’s Health Emergencies Programme, said during a press briefing with reporters on Monday.

When it comes specifically to the novel coronavirus disease or Covid-19, “what we don’t understand yet in Covid-19 are the absolute transmission dynamics,” Ryan said.

“We’re in a phase of preparedness for a potential pandemic,” he said. “Let’s focus on what we can do and what we need to do, which is prepare. When we mean prepare, we mean prepare to detect cases, prepare to treat cases, prepare to follow contacts, prepare to put in place adequate containment measures.”

‘Pandemics mean different things to different people’

Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said earlier this month that there is no actual scientific, definitive definition of what constitutes a pandemic.

“It really is borderline semantics, to be honest with you,” Fauci said.

He added that there could be arguments on either side as to whether the coronavirus outbreak could be described as a pandemic.

“I think you could have people arguing each end of it,” he said. “Pandemics mean different things to different people.”

In general, the WHO avoids declaring public health situations that are not flu pandemics as pandemics. For flu, the term has been used to describe pandemic influenza preparedness.

Otherwise, the WHO no longer uses an old system that involved describing phases of pandemic influenza as ranging from no reports of human infections to “a pandemic.”

“This change came about because of lessons learned from the 2009 H1N1 experience,” WHO spokesperson Tarik Jasarevic said in an email on Tuesday.

For the novel coronavirus, “groups in various organizations are working to define pandemic for this novel virus, which could take some time. In the meantime, our advice remains the same: Member States are strongly advised to enact plans based on national risk assessments of local circumstances, taking into consideration the information provided by WHO’s global assessments,” Jasarevic said.

In January, the WHO declared the novel coronavirus outbreak a public health emergency of international concern.

“Since then, we have seen cases, clusters and outbreaks reported in multiple countries. Most of these cases, clusters and outbreaks are traceable, meaning that widespread community transmission is not evident. Some countries have even slowed or stopped transmission. They must remain alert for the possibility of reintroduction. There will likely be more cases in more places,” Jasarevic said in his email.