What is a pandemic?

• The description is reserved for an infectious disease threatening lots of people all over the world simultaneously.For eg.the previous ones were H1N1 in 2009, Polio in 2014, Ebola in West Africa in 2014, Zika in 2016, Ebola in the Democratic Republic of Congo in 2019.
• Pandemics are more likely if a virus is brand new, able to infect people easily and can spread from person to person in an efficient and sustained way.Coronavirus appears to tick all of those boxes.With no vaccine or treatment that can prevent it yet, containing its spread is vital.

When is a pandemic declared?

• According to the World Health Organization's (WHO) description of pandemic phases, coronavirus is only a step away from being a pandemic.It is spreading between people and has been seen in many of China's neighbouring countries, as well as further afield.If we start seeing sustained community-level outbreaks in multiple parts of the world, then it will be a pandemic.

The coronavirus outbreak that began late last year in China has now spread to 29 countries, touching every continent except South America and Antarctica.While most of these cases are still in China, the virus is gaining a foothold in other countries, raising fears that the world is on the brink of a pandemic.But what does a pandemic mean, and who decides that this is one?All pandemics start with an outbreak of a new disease in a specific geographic location.If that outbreak becomes larger, but still remains confined to a specific region, it becomes an epidemic.
At that point, the WHO may declare a public health emergency of international concern to raise awareness about it. But once a disease spreads globally, with multiple epidemics across different continents, it truly becomes a pandemic.
In this edition of InDepth, we will focus on these and related aspects of a Pandemic, its phases and the precautions we should exercise.We also look at some of the biggest Pandemics in history.